vmtop.py

#!/usr/bin/python3

# TODO:
#  - system-wide metrics
#  - /sys/devices/system/node/nodeX/numastat
#  - can we get guest throttling data (for live migration) ?
#  - user-controlled list metrics to show, the list is getting large
#  - vmexit rate + reasons
#  - arbitrary groups of processes metrics (kernel threads,
#    middleware, etc)
#  - parallel scrape
#  - filter by name, not just PID

import subprocess
import operator
import threading
import time
import signal
import ctypes
import os
import sys
import argparse
import shutil
import socket
from datetime import datetime

# optional dependencies
# bcc for vmexit
import_failed_bcc = False
try:
    from bcc import BPF
except ImportError:
    import_failed_bcc = True

# prometheus
import_failed_prometheus = False
try:
    from prometheus_client import Gauge
    from prometheus_client import start_http_server
except ImportError:
    import_failed_prometheus = True

# daemon mode
import_failed_daemon = False
try:
    import daemon
except ImportError:
    import_failed_daemon = True

stop = False

def read_str(filename):
    with open(filename, 'r') as fd:
        return fd.read().strip()

def read_int(filename):
    return int(read_str(filename))

def mixrange(s):
    r = []
    for i in s.split(","):
        if "-" not in i:
            r.append(int(i))
        else:
            l, h = map(int, i.split("-"))
            r += range(l, h + 1)
    return r


class QemuThread:
    def __init__(self, vm_pid, cgroup, thread_pid, machine, vhost=False):
        self.vm_pid = vm_pid
        self.machine = machine
        self.thread_pid = thread_pid
        self.last_stealtime = None
        self.last_cputime = None
        self.last_scrape_ts = None
        self.nodes = None
        self.vhost = vhost
        self.cgroup = cgroup
        self.pc_steal = 0.0
        self.pc_util = 0.0
        self.diff_steal = 0
        self.diff_util = 0
        self.diff_ts = 0
        self.warned = False
        self.get_thread_name()
        self.get_thread_cpuset()
        self.get_schedstats()

    def get_thread_name(self):
        if self.vhost is True:
            fpath = '/proc/%s/comm' % (self.thread_pid)
        else:
            fpath = '/proc/%s/task/%s/comm' % (self.vm_pid, self.thread_pid)
        self.thread_name = read_str(fpath)

    def get_thread_cpuset(self):
        try:
            if self.vhost is not True:
                fpath = '/proc/%s/task/%s/cpuset' % (self.vm_pid, self.thread_pid)
            with open(fpath, 'r') as f:
                line = f.read().strip()
                # Cgroup1
                if self.cgroup != 2:
                    self.cpuset = line
                else:
                    # Cgroup2
                    # If cpuset controller is not enabled, then it may just
                    # return "/machine.slice" for the /proc/<pid>/cpuset
                    if line != "/machine.slice":
                        self.cpuset = line
                    else:
                        print("Please check if cpuset controller is enabled")
                        sys.exit(1)
        except:
            # Teardown
            self.nodes = []
            return
        self.nodes = self.machine.get_nodes(self.cpuset)

        if len(self.nodes) != 1:
            # kvm-pit is not pinned, but also mostly idle, no need to
            # warn here
            if 'kvm-pit' in self.thread_name:
                return
            if self.warned is True:
                return
            print("Warning: thread %d from VM %d belongs to multiple nodes, "
                  "node accounting may be inaccurate" % (self.thread_pid,
                      self.vm_pid))
            self.warned = True

    def get_schedstats(self):
        self.last_scrape_ts = time.time() * 1000000000
        if self.vhost is True:
            fpath = '/proc/%s/schedstat' % (self.thread_pid)
        else:
            fpath = '/proc/%s/task/%s/schedstat' % (self.vm_pid, self.thread_pid)
        try:
            stats = read_str(fpath).split(' ')
        except FileNotFoundError:
            # On VM teardown return 0
            self.last_cputime = 0
            self.last_stealtime = 0
            return
        self.last_cputime = int(stats[0])
        self.last_stealtime = int(stats[1])

    def __repr__(self):
        return "%s (%s), util: %0.02f %%, steal: %0.02f %%" % (
                self.thread_name, self.thread_pid, self.pc_util,
                self.pc_steal)

    def refresh_stats(self):
        prev_steal_time = self.last_stealtime
        prev_cpu_time = self.last_cputime
        prev_scrape_ts = self.last_scrape_ts
        self.get_schedstats()
        self.diff_ts = self.last_scrape_ts - prev_scrape_ts
        self.diff_steal = self.last_stealtime - prev_steal_time
        self.diff_util = self.last_cputime - prev_cpu_time
        self.pc_util = self.diff_util / self.diff_ts * 100
        self.pc_steal = self.diff_steal / self.diff_ts * 100


class NIC:
    def __init__(self, vm, name):
        self.vm = vm
        self.name = name
        self.last_scrape_ts = None
        self.last_rx = None
        self.last_tx = None
        self.last_rx_drop = None
        self.last_tx_drop = None
        self.tx_rate = None
        self.rx_rate = None
        self.tx_rate_dropped = None
        self.rx_rate_dropped = None
        self.get_stats()

    def get_stats(self):
        self.last_scrape_ts = time.time()
        # Flipped rx/tx to reflect the VM point of view
        try:
            self.last_rx = read_int(f'/sys/devices/virtual/net/{self.name}/statistics/tx_bytes')
            self.last_tx = read_int(f'/sys/devices/virtual/net/{self.name}/statistics/rx_bytes')
            self.last_rx_dropped = read_int(f'/sys/devices/virtual/net/{self.name}/statistics/tx_dropped')
            self.last_tx_dropped = read_int(f'/sys/devices/virtual/net/{self.name}/statistics/rx_dropped')
        except:
            # VM Teardown
            self.last_rx = 0
            self.last_tx = 0
            self.last_rx_dropped = 0
            self.last_tx_dropped = 0
            return

    def refresh_stats(self):
        prev_scrape_ts = self.last_scrape_ts
        prev_rx = self.last_rx
        prev_tx = self.last_tx
        prev_rx_dropped = self.last_rx_dropped
        prev_tx_dropped = self.last_tx_dropped
        self.get_stats()
        diff_sec = self.last_scrape_ts - prev_scrape_ts
        mb = 1024.0 * 1024.0
        self.rx_rate = ((self.last_rx - prev_rx) * 8) / diff_sec / mb
        self.tx_rate = ((self.last_tx - prev_tx) * 8) / diff_sec / mb
        self.rx_rate_dropped = (self.last_rx_dropped - prev_rx_dropped) / diff_sec
        self.tx_rate_dropped = (self.last_tx_dropped - prev_tx_dropped) / diff_sec


class VM:
    def __init__(self, args, vm_pid, machine):
        self.args = args
        self.vm_pid = vm_pid
        self.machine = machine
        self.name = None
        self.csv = None
        # If the memory is on a different primary node than the vcpus
        self.warned_vcpu_mem_split = False
        # If the vcpus of that VM are running on different nodes
        self.warned_vcpu_split = False
        self.mem_allocated = 0
        self.clear_stats()

        # We assume all the allocated memory was allocated to fit on
        # only one node, we still track the real usage on each node.
        # changes protected by machine.nodes_lock.
        self.mem_primary_node = None
        # If a VM changed node, store it here and update with
        # machine.nodes_lock is held by the vm allocation thread
        self.new_mem_primary_node = None

        # Same thing with vcpus, we try to find the node where most
        # vcpus use and set it as default. If the VM is unpinned or
        # pinned to multiple nodes, we use mem_primary_node as an
        # assumption (and warn).
        # VMs are accounted for in vcpu_primary_node because this tool
        # first metric is CPU usage.
        self.vcpu_primary_node = None
        self.new_vcpu_primary_node = None

        self.mem_used_per_node = {}
        self.total_vcpu_count = 0
        self.total_vcpu_count_per_node = {}

        self.vcpu_threads = {}
        self.emulator_threads = {}
        self.vhost_threads = {}
        self.nics = {}

        self.last_io_scrape_ts = None
        self.last_io_read_bytes = None
        self.last_io_write_bytes = None

        self.last_vmexit_count = 0
        self.last_vmexit_diff = 0

        self.get_vm_info()
        if self.args.csv is not None and self.args.vm is True:
            self.open_vm_csv()
        self.get_threads()
        self.get_node_memory()
        self.refresh_vcpu_primary_node()
        self.check_vcpu_mem_split()
        if self.args.no_nic is not True:
            self.get_nic_info()
        self.refresh_io_stats()

    @property
    def nr_vcpus(self):
        return len(self.vcpu_threads.keys())

    def set_vcpu_primary_node(self, new_node):
        if self.vcpu_primary_node == new_node:
            return
        if self.vcpu_primary_node is not None:
            # We cannot update the primary node directly, because of
            # concurrency between the 2 threads, so if the node needs
            # to be updated, set the new_ value and wait for the
            # alloc thread to update with the lock held.
            self.new_vcpu_primary_node = new_node
        else:
            self.vcpu_primary_node = new_node

    def refresh_vcpu_primary_node(self):
        tmp_primary = None
        for vcpu in self.vcpu_threads.values():
            # if any vcpu is floating to more than one node or we didn't
            # manage to find the node, assign it to the primary memory node
            # we already warned about this.
            if len(vcpu.nodes) != 1:
                self.set_vcpu_primary_node(self.mem_primary_node)
                break
            if tmp_primary is None:
                tmp_primary = vcpu.nodes[0]
            elif vcpu.nodes[0] != tmp_primary:
                self.set_vcpu_primary_node(self.mem_primary_node)
                if self.warned_vcpu_split is False:
                    print(f"Warning: VM {self.name} has vcpus pinned to "
                          f"different nodes, accounting will not be accurate")
                    self.warned_vcpu_split = True
                break
        self.set_vcpu_primary_node(tmp_primary)
        if self.vcpu_primary_node is None:
            print(f"Failed to set the vcpu primary node for VM {self.name}")

    def refresh_vcpu_node(self):
        for vcpu in self.vcpu_threads.values():
            vcpu.get_thread_cpuset()
        self.refresh_vcpu_primary_node()

    def check_vcpu_mem_split(self):
        if self.warned_vcpu_mem_split is True:
            return
        for vcpu in self.vcpu_threads.values():
            if len(vcpu.nodes) == 1 and vcpu.nodes[0] != self.mem_primary_node:
                print(f"Warning: VCPU thread {vcpu.thread_pid} from VM "
                      f"{self.name} is not pinned on the same node as its "
                      f"memory")
                self.warned_vcpu_mem_split = True

    def get_exit_count(self):
        if self.args.vmexit is False:
            return
        try:
            c = self.machine.bpf["exitcount"][ctypes.c_uint(self.vm_pid)].value
            self.last_vmexit_diff = c - self.last_vmexit_count
            self.last_vmexit_count = c
        except:
            pass

    def __str__(self):
        if self.args.vcpu:
            vm = "  - %s (%s), vcpu util: %0.02f%%, vcpu steal: %0.02f%%, " \
                    "vhost util: %0.02f%%, vhost steal: %0.02f%%" \
                 "emulators util: %0.02f%%, emulators steal: %0.02f%%" % (
                    self.name, self.vm_pid,
                    self.vcpu_sum_pc_util,
                    self.vcpu_sum_pc_steal,
                    self.vhost_sum_pc_util,
                    self.vhost_sum_pc_steal,
                    self.emulators_sum_pc_util,
                    self.emulators_sum_pc_steal)
            vcpu_util = ""
            for v in self.vcpu_threads.values():
                vcpu_util = "%s\n    - %s" % (vcpu_util, v)
            emulators_util = ""
            if self.args.emulators:
                for v in self.emulator_threads.values():
                    emulators_util = "%s\n    - %s" % (emulators_util, v)
            return "%s%s%s" % (vm, vcpu_util, emulators_util)
        else:
            metrics = [self.name, str(self.vm_pid)]
            for i in self.args.display_metrics:
                if i == 'vcpu_sum_pc_util':
                    metrics.append('%0.02f' % self.vcpu_sum_pc_util)
                elif i == 'vcpu_sum_pc_steal':
                    metrics.append('%0.02f' % self.vcpu_sum_pc_steal)
                elif i == 'emulators_sum_pc_util':
                    metrics.append('%0.02f' % self.emulators_sum_pc_util)
                elif i == 'emulators_sum_pc_steal':
                    metrics.append('%0.02f' % self.emulators_sum_pc_steal)
                elif i == 'vhost_sum_pc_util':
                    metrics.append('%0.02f' % self.vhost_sum_pc_util)
                elif i == 'vhost_sum_pc_steal':
                    metrics.append('%0.02f' % self.vhost_sum_pc_steal)
                elif i == 'mb_read':
                    metrics.append('%0.02f' % self.mb_read)
                elif i == 'mb_write':
                    metrics.append('%0.02f' % self.mb_write)
                elif i == 'rx_rate':
                    metrics.append('%0.02f' % self.rx_rate)
                elif i == 'tx_rate':
                    metrics.append('%0.02f' % self.tx_rate)
                elif i == 'rx_rate_dropped':
                    metrics.append('%0.02f' % self.rx_rate_dropped)
                elif i == 'tx_rate_dropped':
                    metrics.append('%0.02f' % self.tx_rate_dropped)
                elif i == 'last_vmexit_diff':
                    metrics.append('%d' % self.last_vmexit_diff)
            return self.args.vm_format.format(*metrics)

    def open_vm_csv(self):
        fname = os.path.join(self.args.csv, "%s.csv" % self.name)
        self.csv = open(fname, 'w')
        self.csv.write("timestamp,pid,name,mem_node,vcpu_node,vcpu_util,vcpu_steal,emulators_util,"
                "emulators_steal,vhost_util,vhost_steal,disk_read,disk_write,rx,tx,"
                "rx_dropped,tx_dropped,vmexit_count\n")

    def output_vm_csv(self, timestamp):
        # Output the CSV file
        # we use abs() because Python manages to write -0.00 once in a
        # while...
        self.csv.write(f"{datetime.fromtimestamp(timestamp)},"
                       f"{self.vm_pid},{self.name},"
                       f"{self.mem_primary_node.id},"
                       f"{self.vcpu_primary_node.id},"
                       f"{'%0.02f' % (abs(self.vcpu_sum_pc_util))},"
                       f"{'%0.02f' % (abs(self.vcpu_sum_pc_steal))},"
                       f"{'%0.02f' % (abs(self.emulators_sum_pc_util))},"
                       f"{'%0.02f' % (abs(self.emulators_sum_pc_steal))},"
                       f"{'%0.02f' % (abs(self.vhost_sum_pc_util))},"
                       f"{'%0.02f' % (abs(self.vhost_sum_pc_steal))},"
                       f"{'%0.02f' % (abs(self.mb_read))},"
                       f"{'%0.02f' % (abs(self.mb_write))},"
                       f"{'%0.02f' % (abs(self.rx_rate))},"
                       f"{'%0.02f' % (abs(self.tx_rate))},"
                       f"{'%0.02f' % (abs(self.rx_rate_dropped))},"
                       f"{'%0.02f' % (abs(self.tx_rate_dropped))},"
                       f"{'%d' % (self.last_vmexit_diff)}\n")
        self.csv.flush()

    def get_nic_info(self):
        for fd in os.listdir(f'/proc/{self.vm_pid}/fd/'):
            lname = f'/proc/{self.vm_pid}/fd/{fd}'
            try:
                link = os.readlink(lname)
            except OSError:
                continue

            if link == '/dev/net/tun':
                try:
                    with open(f'/proc/{self.vm_pid}/fdinfo/{fd}', 'r') as _f:
                        fdinfo = _f.read().split('\n')
                except FileNotFoundError:
                    # Ignore fd that vanished
                    continue

                for l in fdinfo:
                    l = l.split()
                    if len(l) ==2 and l[0] == 'iff:':
                        self.nics[l[1]] = NIC(self, l[1])

    def get_threads(self):
        for tid in os.listdir('/proc/%s/task/' % self.vm_pid):
            fname = '/proc/%s/task/%s/comm' % (self.vm_pid, tid)
            try:
                with open(fname, 'r') as _f:
                    comm = _f.read()
                tid = int(tid)
                thread = QemuThread(self.vm_pid, self.machine.cgroup, tid, self.machine)
            except FileNotFoundError:
                # Ignore threads that disappear for now (temporary workers)
                continue
            if 'CPU' in comm:
                self.vcpu_threads[tid] = thread
            else:
                self.emulator_threads[tid] = thread

        # Find vhost threads
        cmd = ["pgrep", str(self.vm_pid)]
        pids = subprocess.check_output(
                cmd, shell=False).strip().decode("utf-8").split('\n')
        for p in pids:
            tid = int(p)
            thread = QemuThread(self.vm_pid, self.machine.cgroup, tid, self.machine, vhost=True)
            self.vhost_threads[tid] = thread

    def get_vm_info(self):
        with open('/proc/%s/cmdline' % self.vm_pid, mode='r') as fh:
            cmdline = fh.read().split('\0')
        for i in range(len(cmdline)):
            if cmdline[i].startswith('guest='):
                self.name = cmdline[i].split('=')[1].split(',')[0]
            elif cmdline[i].startswith('-name'):
                self.name = cmdline[i+1]
            elif cmdline[i] == '-m':
                self.mem_allocated = int(cmdline[i+1])
            elif cmdline[i] == '-smp':
                self.total_vcpu_count = int(cmdline[i+1].split(',')[0])

        if self.name is None:
            print("Failed to parse guest name")
            self.name = "unknown"

    def refresh_io_stats(self):
        self.last_io_scrape_ts = time.time()
        try:
            with open('/proc/%s/io' % self.vm_pid, 'r') as f:
                stats = f.read().split('\n')
        except FileNotFoundError:
            # On VM teardown return 0
            self.last_io_read_bytes = 0
            self.last_io_write_bytes = 0
            return

        for l in stats:
            l = l.split(' ')
            if l[0] == 'read_bytes:':
                self.last_io_read_bytes = int(l[1])
            if l[0] == 'write_bytes:':
                self.last_io_write_bytes = int(l[1])

    def get_node_memory(self):
        cmd = ["numastat", "-p", str(self.vm_pid)]
        try:
            usage = subprocess.check_output(
                    cmd,
                    shell=False).decode("utf-8").split('\n')[-2].split()[1:-1]
        except subprocess.CalledProcessError:
            # ctrl-c
            return
        maxnode = None
        maxmem = 0
        for node_id in range(len(usage)):
            try:
                mem = float(usage[node_id])
            except ValueError:
                # Teardown
                return
            self.mem_used_per_node[node_id] = mem
            if maxnode is None or mem > maxmem:
                maxnode = node_id
                maxmem = mem

        if self.mem_primary_node is None:
            self.mem_primary_node = self.machine.nodes[maxnode]
        elif self.mem_primary_node != self.machine.nodes[maxnode]:
            self.new_mem_primary_node = self.machine.nodes[maxnode]

    def clear_stats(self):
        self.vcpu_sum_pc_util = 0
        self.vcpu_sum_pc_steal = 0
        self.vhost_sum_pc_util = 0
        self.vhost_sum_pc_steal = 0
        self.emulators_sum_pc_util = 0
        self.emulators_sum_pc_steal = 0

    def refresh_stats(self):
        self.clear_stats()
        # sum of all vcpu stats
        for vcpu in self.vcpu_threads.values():
            vcpu.refresh_stats()
            self.vcpu_sum_pc_util += vcpu.pc_util
            self.vcpu_sum_pc_steal += vcpu.pc_steal

        # vhost
        for vhost in self.vhost_threads.values():
            vhost.refresh_stats()
            self.vhost_sum_pc_util += vhost.pc_util
            self.vhost_sum_pc_steal += vhost.pc_steal

        # emulators
        to_remove = []
        for emulator in self.emulator_threads.values():
            try:
                emulator.refresh_stats()
            except Exception:
                to_remove.append(emulator)
                continue
            self.emulators_sum_pc_util += emulator.pc_util
            self.emulators_sum_pc_steal += emulator.pc_steal
        # workers are added/removed on demand, so we can't keep track of all
        # FIXME
#        for r in to_remove:
#            del emulators

        # disk
        prev_io_scrape_ts = self.last_io_scrape_ts
        prev_io_read_bytes = self.last_io_read_bytes
        prev_io_write_bytes = self.last_io_write_bytes
        self.refresh_io_stats()
        diff_sec = self.last_io_scrape_ts - prev_io_scrape_ts
        mb = 1024.0*1024.0
        self.mb_read = (self.last_io_read_bytes - prev_io_read_bytes) / diff_sec / mb
        self.mb_write = (self.last_io_write_bytes - prev_io_write_bytes) / diff_sec / mb

        self.tx_rate = 0
        self.rx_rate = 0
        self.tx_rate_dropped = 0
        self.rx_rate_dropped = 0
        if not self.args.no_nic:
            for n in self.nics.values():
                n.refresh_stats()
                self.tx_rate += n.tx_rate
                self.rx_rate += n.rx_rate
                self.tx_rate_dropped += n.tx_rate_dropped
                self.rx_rate_dropped += n.rx_rate_dropped

        # copy to node stats
        self.vcpu_primary_node.node_vcpu_sum_pc_util += self.vcpu_sum_pc_util
        self.vcpu_primary_node.node_vcpu_sum_pc_steal += self.vcpu_sum_pc_steal
        self.vcpu_primary_node.node_vhost_sum_pc_util += self.vhost_sum_pc_util
        self.vcpu_primary_node.node_vhost_sum_pc_steal += self.vhost_sum_pc_steal
        self.vcpu_primary_node.node_emulators_sum_pc_util += self.emulators_sum_pc_util
        self.vcpu_primary_node.node_emulators_sum_pc_steal += self.emulators_sum_pc_steal

        self.get_exit_count()


class Node:
    def __init__(self, _id, args):
        self.id = _id
        self.args = args
        self.hwthread_list = Node.node_hwthreads(_id)

        # Approximation, VMs could be split between nodes, we use the node
        # where most of the memory is allocated to decide here
        self.node_vms = {}

        # After the initial scan, the resource accounting is owned by the
        # refresh_vm_allocation thread
        # Approximation, assumes all the allocated memory is not split
        self.vm_mem_allocated = 0
        self.vm_mem_used = 0
        self.node_vcpu_threads = 0

        self.clear_stats()

    def clear_stats(self):
        # Owned by the main loop
        self.node_vcpu_sum_pc_util = 0
        self.node_vcpu_sum_pc_steal = 0
        self.node_vhost_sum_pc_util = 0
        self.node_vhost_sum_pc_steal = 0
        self.node_emulators_sum_pc_util = 0
        self.node_emulators_sum_pc_steal = 0

    def refresh_vm_allocation(self):
        tmp_vm_mem_allocated = 0
        for vm in self.node_vms.values():
            vm.get_node_memory()
            vm.refresh_vcpu_node()
            tmp_vm_mem_allocated += vm.mem_allocated
        self.vm_mem_allocated = tmp_vm_mem_allocated

    def print_node_initial_count(self):
        if self.args.csv is not None:
            return
        return("%s VMs (%s vcpus, %0.02f GB mem allocated, "
              "%0.02f GB mem used)" % (
                self.nr_vms, self.node_vcpu_threads,
                self.vm_mem_allocated/1024, self.vm_mem_used/1024))

    def open_csv_file(self):
        fname = os.path.join(self.args.csv, 'node%d.csv' % self.id)
        print("Writing node %s data in %s" % (self.id, fname))
        self.node_csv = open(fname, 'w')
        self.node_csv.write("timestamp,id,nr_vms,nr_vcpus,vm_mem_allocated,"
                            "vm_mem_used,vcpu_util,vcpu_steal,emulators_util,"
                            "emulators_steal,vhost_util,vhost_steal\n")

    def output_node_csv(self, timestamp):
        self.node_csv.write(f"{datetime.fromtimestamp(timestamp)},"
                            f"{self.id},"
                            f"{self.nr_vms},"
                            f"{self.node_vcpu_threads},"
                            f"{self.vm_mem_allocated/1024},"
                            f"{self.vm_mem_used/1024},"
                            f"{'%0.02f' % (self.node_vcpu_sum_pc_util)},"
                            f"{'%0.02f' % (self.node_vcpu_sum_pc_steal)},"
                            f"{'%0.02f' % (self.node_emulators_sum_pc_util)},"
                            f"{'%0.02f' % (self.node_emulators_sum_pc_steal)},"
                            f"{'%0.02f' % (self.node_vhost_sum_pc_util)},"
                            f"{'%0.02f' % (self.node_vhost_sum_pc_steal)}\n")
        self.node_csv.flush()

    def output_allocation(self):
        print("  Node %d: %s" % (self.id, self.print_node_initial_count()))

    # -1 when no numa nodes
    def node_list():
        if os.path.exists('/sys/devices/system/node/online'):
            return mixrange(read_str('/sys/devices/system/node/online'))
        else:
            return [-1]

    def node_hwthreads(node_n):
        if node_n == -1:
            return mixrange(read_str('/sys/devices/system/cpu/online'))
        else:
            return mixrange(read_str(f'/sys/devices/system/node/node{node_n}/cpulist'))

    @property
    def nr_vms(self):
        return len(self.node_vms)

    @property
    def nr_hwthreads(self):
        return len(self.hwthread_list)


class Machine:
    def __init__(self, args):
        self.args = args

        # to read/update node_vms in each node, prevents concurrent
        # accesses by the main loop and the vm_allocation thread
        self.nodes_lock = threading.Lock()

        # Protect concurrent reads and writes to the all_vms dict
        self.all_vms_lock = threading.Lock()

        self.nodes = {}
        self.all_vms = {}
        self.cgroup = self.check_cgroup()
        self.get_cpuset_mount_point()
        self.cancel = False

        self.get_machine_stat()

        for n in Node.node_list():
            self.nodes[n] = Node(n, self.args)

    def refresh_machine_stats(self):
        nr_hwthreads = self.nr_hwthreads
        prev_user = self.last_cpu_user
        prev_nice = self.last_cpu_nice
        prev_system = self.last_cpu_system
        prev_idle = self.last_cpu_idle
        prev_iowait = self.last_cpu_iowait
        prev_irq = self.last_cpu_irq
        prev_softirq = self.last_cpu_softirq
        prev_guest = self.last_cpu_guest
        prev_ts = self.last_scrape_ts
        self.get_machine_stat()
        diff = (self.last_scrape_ts - prev_ts) * nr_hwthreads
        self.pc_user = (self.last_cpu_user - prev_user) / diff
        self.pc_nice = (self.last_cpu_nice - prev_nice) / diff
        self.pc_system = (self.last_cpu_system - prev_system) / diff
        self.pc_idle = (self.last_cpu_idle - prev_idle) / diff
        self.pc_iowait = (self.last_cpu_iowait - prev_iowait) / diff
        self.pc_irq = (self.last_cpu_irq - prev_irq) / diff
        self.pc_softirq = (self.last_cpu_softirq - prev_softirq) / diff
        self.pc_guest = (self.last_cpu_guest - prev_guest) / diff

    def __repr__(self):
        return (f"Host CPU: user: {'%0.02f%%' % self.pc_user}, "
              f"nice: {'%0.02f%%' % self.pc_nice}, "
              f"system: {'%0.02f%%' % self.pc_system}, "
              f"idle: {'%0.02f%%' % self.pc_idle}, "
              f"iowait: {'%0.02f%%' % self.pc_iowait}, "
              f"irq: {'%0.02f%%' % self.pc_irq}, "
              f"guest: {'%0.02f%%' % self.pc_guest}")

    def open_csv_file(self):
        fname = os.path.join(self.args.csv, 'host.csv')
        print("Writing host data in %s" % (fname))
        self.machine_csv = open(fname, 'w')
        self.machine_csv.write("timestamp,cpu_user,cpu_nice,cpu_system,"
                               "cpu_idle,cpu_iowait,cpu_irq,cpu_guest\n")
        self.machine_csv.flush()

    def output_machine_csv(self, timestamp):
        self.machine_csv.write(f"{datetime.fromtimestamp(timestamp)},"
                            f"{'%0.02f' % self.pc_user},"
                            f"{'%0.02f' % self.pc_nice},"
                            f"{'%0.02f' % self.pc_system},"
                            f"{'%0.02f' % self.pc_idle},"
                            f"{'%0.02f' % self.pc_iowait},"
                            f"{'%0.02f' % self.pc_irq},"
                            f"{'%0.02f' % self.pc_guest}\n")

    def get_machine_stat(self):
        self.last_scrape_ts = time.time()
        with open('/proc/stat', 'r') as f:
            cpu = f.readline().split()
        self.last_cpu_user = int(cpu[1])
        self.last_cpu_nice = int(cpu[2])
        self.last_cpu_system = int(cpu[3])
        self.last_cpu_idle = int(cpu[4])
        self.last_cpu_iowait = int(cpu[5])
        self.last_cpu_irq = int(cpu[6])
        self.last_cpu_softirq = int(cpu[7])
        self.last_cpu_guest = int(cpu[9])

    def check_cgroup(self):
        # Check if cgroup2 is configured
        cgroup2_path = "/sys/fs/cgroup/cgroup.controllers"
        isfile = os.path.exists(cgroup2_path)
        if isfile:
            return(2)
        else:
            return(1)

    def get_cpuset_mount_point(self):
        with open('/proc/mounts', 'r') as f:
            mounts = f.read().split('\n')
        for m in mounts:
            m = m.split()

            # Avoid scenrio where m is empty
            if m:
                if m[0] == 'cgroup':
                    if 'unified' in m[1]:
                        continue
                    if 'cpuset' in m[3]:
                        self.cpuset_mount_point = m[1]
                        return
                    elif 'cgroup2' in m[2]:
                        self.cpuset_mount_point = m[1]
                        return
        if self.cpuset_mount_point is None:
            print("Cgroup cpuset path not found")


    def refresh_stats(self):
        for node in self.nodes.values():
            node.clear_stats()
        try:
            self.all_vms_lock.acquire()
            for vm in self.all_vms.values():
                vm.refresh_stats()
        finally:
            self.all_vms_lock.release()
        # Normalize by CPU count
        for node in self.nodes.values():
            node.node_vcpu_sum_pc_util /= node.nr_hwthreads
            node.node_vcpu_sum_pc_steal /= node.nr_hwthreads
            node.node_vhost_sum_pc_util /= node.nr_hwthreads
            node.node_vhost_sum_pc_steal /= node.nr_hwthreads
            node.node_emulators_sum_pc_util /= node.nr_hwthreads
            node.node_emulators_sum_pc_steal /= node.nr_hwthreads

        self.refresh_machine_stats()

    def account_vcpus(self):
        tmp = {}
        for node_id in self.nodes.keys():
            tmp[node_id] = 0
        for vm in self.all_vms.values():
            tmp[vm.vcpu_primary_node.id] += len(vm.vcpu_threads.keys())
        for node_id in self.nodes.keys():
            self.nodes[node_id].node_vcpu_threads = tmp[node_id]

    def refresh_vm_allocation(self):
        while True:
            # Sleep 1s between scans
            for i in range(10):
                if stop is True:
                    return
                time.sleep(0.1)
            self.list_vms()
            self.refresh_mem_allocation()
            for vm in self.all_vms.values():
                # If a VM switched memory node
                if vm.new_mem_primary_node is not None:
                    try:
                        self.nodes_lock.acquire()
                        vm.mem_primary_node.vm_mem_allocated -= vm.mem_allocated
                        vm.new_mem_primary_node.vm_mem_allocated += vm.mem_allocated
                        vm.mem_primary_node = vm.new_mem_primary_node
                        vm.new_mem_primary_node = None
                    finally:
                        self.nodes_lock.release()
                # If a VM switched vcpu node
                if vm.new_vcpu_primary_node is not None:
                    try:
                        self.nodes_lock.acquire()
                        del vm.vcpu_primary_node.node_vms[vm.vm_pid]
                        vm.vcpu_primary_node.node_vcpu_threads -= vm.nr_vcpus

                        vm.new_vcpu_primary_node.node_vms[vm.vm_pid] = vm
                        vm.new_vcpu_primary_node.node_vcpu_threads += vm.nr_vcpus
                        vm.vcpu_primary_node = vm.new_vcpu_primary_node
                        vm.new_vcpu_primary_node = None
                    finally:
                        self.nodes_lock.release()
            self.account_vcpus()

    def print_initial_count(self):
        for node in self.nodes.values():
            self.print_node_count(node.id)

    def print_node_count(self, node_id):
        node = self.nodes[node_id]
        node.output_allocation()

    def get_nodes(self, cpuset):
        nodes = []
        fullpath = "%s/%s/cpuset.cpus" % (self.cpuset_mount_point, cpuset)
        if os.path.exists(fullpath):
            with open(fullpath, 'r') as f:
                cpus = mixrange(f.read())
            for c in cpus:
                for n in self.nodes.values():
                    if c in n.hwthread_list:
                        if n not in nodes:
                            nodes.append(n)
                        break
            return nodes

    @property
    def nr_nodes(self):
        return len(self.nodes)

    @property
    def nr_hwthreads(self):
        nr = 0
        for n in self.nodes.values():
            nr += len(n.hwthread_list)
        return nr

    def del_vm(self, pid):
        v = self.all_vms[pid]
        del v.vcpu_primary_node.node_vms[pid]
        try:
            self.all_vms_lock.acquire()
            del self.all_vms[pid]
        finally:
            self.all_vms_lock.release()

    def refresh_mem_allocation(self):
        tmp_vm_used_per_node = {}
        for node in self.nodes.values():
            if self.cancel is True:
                return
            tmp_vm_used_per_node[node.id] = 0
            node.refresh_vm_allocation()

        for vm in self.all_vms.values():
            for node_id in vm.mem_used_per_node.keys():
                tmp_vm_used_per_node[node_id] += vm.mem_used_per_node[node_id]

        for node_id in self.nodes.keys():
            self.nodes[node_id].vm_mem_used = tmp_vm_used_per_node[node_id]

    def list_vms(self, progress=False):
        cmd = ["pgrep", "qemu"]
        try:
            pids = subprocess.check_output(
                    cmd, shell=False).strip().decode("utf-8").split('\n')
        except subprocess.CalledProcessError:
            l = list(self.all_vms.keys())
            for v in l:
                self.del_vm(v)
            return
        except KeyboardInterrupt:
            return
        # to track the VMs that have disappeared since the last scan
        previous_vm_list = list(self.all_vms.keys())
        nr = 0
        for pid in pids:
            if self.cancel is True:
                return
            nr += 1
            if progress is True:
                print("%d VMs" % nr, end='\r')
            pid = int(pid)
            if pid in self.all_vms.keys():
                previous_vm_list.remove(pid)
                continue
            try:
                v = VM(self.args, pid, self)
            except KeyboardInterrupt:
                return
            except:
                print("Unexpected error on VM creation:", sys.exc_info())
                continue
            v.vcpu_primary_node.node_vms[pid] = v
            try:
                self.all_vms_lock.acquire()
                self.all_vms[pid] = v
            finally:
                self.all_vms_lock.release()

        if progress is True:
            print("%d VMs" % nr)
            print("Done")

        if len(previous_vm_list) != 0:
            for pid in previous_vm_list:
                self.del_vm(pid)

    def attach_bpf(self):
        bpf_text = """
#include <uapi/linux/ptrace.h>
BPF_HASH(exitcount, u32, uint32_t);

TRACEPOINT_PROBE(kvm, kvm_exit)
{
    exitcount.increment(bpf_get_current_pid_tgid() >> 32);
    return 0;
}
"""
        self.bpf = BPF(text=bpf_text)

class VmTop:
    def __init__(self, args):
        self.args = args
        self.machine = Machine(self.args)

        print("Collecting VM informations...")

        if self.args.csv is not None:
            self.csv = True
            self.open_csv_files()
        else:
            self.csv = False

        if self.args.vmexit is True:
            self.machine.attach_bpf()

        # Initial list and allocation accounting
        self.machine.list_vms(progress=True)
        self.machine.refresh_mem_allocation()
        self.machine.account_vcpus()
        if self.csv is False:
            self.machine.print_initial_count()

        self.setup_prometheus()

        # Scan for new VMs and memory/vcpu allocation in the background
        self.vm_alloc_thread = threading.Thread(
                target=self.machine.refresh_vm_allocation)
        self.vm_alloc_thread.start()

    def setup_prometheus(self):
        if not self.args.prometheus:
            return
        self.vm_mb_read_gauge = Gauge("vm_mbread", "mb read for vm", ['vm'])
        self.vm_mb_write_gauge = Gauge("vm_mbwrite", "mb write for vm", ['vm'])
        self.vm_rx_rate_gauge = Gauge("vm_rxrate", "rx rate for vm", ['vm'])
        self.vm_tx_rate_gauge = Gauge("vm_txrate", "tx rate for vm", ['vm'])
        self.vm_rx_rate_dropped_gauge = Gauge("vm_rxratedropped", "rx drop rate for vm", ['vm'])
        self.vm_tx_rate_dropped_gauge = Gauge("vm_txrateddropped", "tx drop rate for vm", ['vm'])
        self.vm_vcpu_util_gauge = Gauge("vm_vcpu_util", "VCPU util", ['vm'])
        self.vm_vcpu_steal_gauge = Gauge("vm_vcpu_steal", "VCPU util", ['vm'])
        self.vm_vhost_util_gauge = Gauge("vm_vhost_util", "vhost util", ['vm'])
        self.vm_vhost_steal_gauge = Gauge("vm_vhost_steal", "vhost steal", ['vm'])
        self.vm_emulators_util_gauge = Gauge("vm_emulators_util", "emulators util", ['vm'])
        self.vm_emulators_steal_gauge = Gauge("vm_emulators_steal", "emulators steal", ['vm'])
        if self.args.vmexit is True:
            self.vm_vmexits_gauge = Gauge("vm_vmexit_rate", "vm exit rate", ['vm'])

        self.vcpu_util_gauge = Gauge("node_vcpuutil", "VCPU util", ['node'])
        self.vcpu_steal_gauge = Gauge("node_vcpusteal", "VCPU util", ['node'])
        self.vhost_util_gauge = Gauge("node_vhostutil", "vhost util", ['node'])
        self.vhost_steal_gauge = Gauge("node_vhoststeal", "vhost steal", ['node'])
        self.emulators_util_gauge = Gauge("node_emulatorutil", "emulators util", ['node'])
        self.emulators_steal_gauge = Gauge("node_emulatorsteal", "emulators steal", ['node'])


    def open_csv_files(self):
        try:
            os.mkdir(self.args.csv)
        except FileExistsError:
            print("Error: folder %s already exists, aborting" % self.args.csv)
            sys.exit(1)
        self.machine.open_csv_file()
        for n in self.machine.nodes.values():
            n.open_csv_file()
        if self.args.vm is True:
            print("Writing per-VM csv file")
        else:
            print("NOT writing per-VM data")

    def check_diskspace(self):
        # Be nice and abort if disk left is less than 1GB
        if self.args.csv is not None:
            if shutil.disk_usage(self.args.csv)[2] < 1*1024*1024*1024:
                print("Less than 1GB available on disk, exiting")
                return False

        return True

    def check_balance(self):
        # PoC, lots of assumptions here...
        # Try to optimize the load by proposing a balance between nodes:
        # - find the busiest node
        # - if above a threshold:
        #   - find the busiest VM running there
        #   - find the calmest VM on the other node with the same allocation
        #     - if no VM of the same size is found, use more than one (TODO)
        #   - propose a swap
        if not self.args.balance or self.machine.nr_nodes < 2:
            return

        busiest_node_steal = 0
        busiest_node = None
        calmest_node_steal = None
        calmest_node = None
        # Find the busiest and calmest nodes
        for node in self.machine.nodes.values():
            if node.vcpu_sum_pc_steal > busiest_node_steal:
                busiest_node_steal = node.vcpu_sum_pc_steal
                busiest_node = node
            if calmest_node_steal is None or node.vcpu_sum_pc_steal < calmest_node_steal:
                calmest_node_steal = node.vcpu_sum_pc_steal
                calmest_node = node

        # Not enough steal or capacity
        if busiest_node_steal < 10 or calmest_node_steal > 1:
            return

        # Find the best order to swap (we temporarily need twice the memory
        # capacity on one of the nodes)
        to_calm = None
        if busiest_node.vm_mem_used < calmest_node.vm_mem_used:
            to_calm = False
        else:
            to_calm = True

        busiest_vm = sorted(busiest_node.node_vms.values(),
                            key=operator.attrgetter("vcpu_sum_pc_util"),
                            reverse=True)[0]

        calmest_vm = None
        try:
            self.machine.nodes_lock.acquire()
            for vm in sorted(calmest_node.node_vms.values(),
                            key=operator.attrgetter("vcpu_sum_pc_util"),
                            reverse=False):
                if vm.vcpu_sum_pc_util > 60:
                    break
                if vm.nr_vcpus == busiest_vm.nr_vcpus and \
                        vm.mem_allocated == busiest_vm.mem_allocated:
                    calmest_vm = vm
                    break
        finally:
            self.machine.nodes_lock.release()

        if calmest_vm is None:
            print("Didn't find a candidate to swap with %s (%s): %d vcpus, %m mem" % (
                busiest_vm.name, busiest_vm.vm_pid, busiest_vm.nr_vcpus,
                busiest_vm.mem_allocated))
            return

        if to_calm is True:
            print(f"Would migrate {busiest_vm.name} ({busiest_vm.vm_pid}) "
                  f"{'%0.02f%%' % (busiest_vm.vcpu_sum_pc_util)} from node "
                  f"{busiest_node.id} to node {calmest_node.id}")
            print(f"Would migrate {calmest_vm.name} ({calmest_vm.vm_pid}) "
                  f"{'%0.02f%%' % (calmest_vm.vcpu_sum_pc_util)} from node "
                  f"{calmest_node.id} to node {busiest_node.id}")
        else:
            print(f"Would migrate {calmest_vm.name} ({calmest_vm.vm_pid}) "
                  f"{'%0.02f%%' % (calmest_vm.vcpu_sum_pc_util)} from node "
                  f"{calmest_node.id} to node {busiest_node.id}")
            print(f"Would migrate {busiest_vm.name} ({busiest_vm.vm_pid}) "
                  f"{'%0.02f%%' % (busiest_vm.vcpu_sum_pc_util)} from node "
                  f"{busiest_node.id} to node {calmest_node.id}")


    def stop(self):
        exit_gracefully(0, 0)
        if self.vm_alloc_thread.is_alive():
            self.vm_alloc_thread.join()

    def run_once(self):
        if self.check_diskspace() == False:
            self.stop()
            return

        self.machine.refresh_stats()
        self.check_balance()

        if self.csv is False:
            print("\n%s" % datetime.today())
        else:
            timestamp = int(time.time())
        if self.csv:
            self.machine.output_machine_csv(timestamp)
        else:
            print(self.machine)

        # Prevent the list of VMs per node to be updated during output
        with self.machine.nodes_lock:
            for node in self.machine.nodes.keys():
                if self.args.node is not None:
                    if node not in self.args.node:
                        continue
                nr = 0
                node = self.machine.nodes[node]
                if self.args.vm and self.csv is False:
                    print("Node %d:" % node.id)
                    if not self.args.vcpu:
                        first_row = ['name', 'PID']
                        for i in self.args.display_metrics:
                            first_row.append(self.args.vm_metrics[i][0])
                        second_row = ['', '']
                        for i in self.args.display_metrics:
                            second_row.append(self.args.vm_metrics[i][1])
                        print(self.args.vm_format.format(*first_row))
                        print(self.args.vm_format.format(*second_row))
                for vm in (sorted(node.node_vms.values(),
                                  key=operator.attrgetter(self.args.sort),
                                  reverse=True)):
                    if self.args.vm:
                        if self.args.pid is not None:
                            if vm.vm_pid in self.args.pids:
                                print(vm)
                        else:
                            if self.args.limit is not None and \
                                    nr >= self.args.limit:
                                break
                            if self.csv is True:
                                vm.output_vm_csv(timestamp)
                            else:
                                print(vm)
                            nr += 1
                    if self.args.prometheus:
                        self.vm_vcpu_util_gauge.labels(vm=vm.name).set(vm.vcpu_sum_pc_util)
                        self.vm_vcpu_steal_gauge.labels(vm=vm.name).set(vm.vcpu_sum_pc_steal)
                        self.vm_vhost_util_gauge.labels(vm=vm.name).set(vm.vhost_sum_pc_util)
                        self.vm_vhost_steal_gauge.labels(vm=vm.name).set(vm.vhost_sum_pc_steal)
                        self.vm_emulators_util_gauge.labels(vm=vm.name).set(vm.emulators_sum_pc_util)
                        self.vm_emulators_steal_gauge.labels(vm=vm.name).set(vm.emulators_sum_pc_steal)
                        self.vm_mb_read_gauge.labels(vm=vm.name).set(vm.mb_read)
                        self.vm_mb_write_gauge.labels(vm=vm.name).set(vm.mb_write)
                        self.vm_rx_rate_gauge.labels(vm=vm.name).set(vm.rx_rate)
                        self.vm_tx_rate_gauge.labels(vm=vm.name).set(vm.tx_rate)
                        self.vm_rx_rate_dropped_gauge.labels(vm=vm.name).set(vm.rx_rate_dropped)
                        self.vm_tx_rate_dropped_gauge.labels(vm=vm.name).set(vm.tx_rate_dropped)
                        if self.args.vmexit is True:
                            self.vm_vmexits_gauge.labels(vm=vm.name).set(vm.last_vmexit_diff)

                if self.csv:
                    node.output_node_csv(timestamp)
                else:
                    print("  Node %d: vcpu util: %0.02f%%, "
                          "vcpu steal: %0.02f%%, emulators util: %0.02f%%, "
                          "emulators steal: %0.02f%%" % (
                              node.id,
                              node.node_vcpu_sum_pc_util,
                              node.node_vcpu_sum_pc_steal,
                              node.node_emulators_sum_pc_util,
                              node.node_emulators_sum_pc_steal))
                    self.machine.print_node_count(node.id)

                if self.args.prometheus:
                    self.vcpu_util_gauge.labels(node=node.id).set(node.node_vcpu_sum_pc_util)
                    self.vcpu_steal_gauge.labels(node=node.id).set(node.node_vcpu_sum_pc_steal)
                    self.vhost_util_gauge.labels(node=node.id).set(node.node_vhost_sum_pc_util)
                    self.vhost_steal_gauge.labels(node=node.id).set(node.node_vhost_sum_pc_steal)
                    self.emulators_steal_gauge.labels(node=node.id).set(node.node_emulators_sum_pc_util)
                    self.emulators_steal_gauge.labels(node=node.id).set(node.node_emulators_sum_pc_steal)


        time.sleep(self.args.refresh)

    def loop(self):
        while stop == False:
            self.run_once()
        self.stop()

    def run(self, ntimes):
        for _ in range(ntimes):
            self.run_once()
        self.stop()

def exit_gracefully(signum, frame):
    global stop
    stop = True

def start_prometheus_client(ip, port):
    start_http_server(int(port), ip)
    s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    ret = s.connect_ex((ip, int(port)))
    if ret == 0:
        print("Prometheus listening on %s:%s" %(ip, port))
    else:
        print("Prometheus not listening on %s:%s. Please check if the specified port is not in use already" %(ip, port))
        exit(1)

def parse_args():
    parser = argparse.ArgumentParser(description='Monitor local steal')
    parser.add_argument('-r', '--refresh', type=int, default=1,
                        help='refresh rate (seconds)')
    parser.add_argument('-l', '--limit', type=int,
                        help='limit to top X VMs per node')
    parser.add_argument('-n', '--number', type=int, default=0,
                        help='gather stats N times and exit')
    parser.add_argument('-s', '--sort', type=str,
                        choices=['vcpu_util', 'vcpu_steal',
                                 'vhost_util', 'vhost_steal',
                                 'disk_read', 'disk_write',
                                 'emulators_util', 'emulators_steal',
                                 'rx', 'tx', 'rx_dropped', 'tx_dropped'],
                        default='vcpu_util',
                        help='sort order for VM list, default: vcpu_util')
    parser.add_argument('-p', '--pid', type=str,
                        help='Limit to pid (csv), implies --vm')
    parser.add_argument('--vcpu', action='store_true',
                        help='show vcpu stats (implies --vm)')
    parser.add_argument('--daemon', action='store_true',
                        help='daemonize vmtop (works with --csv or --prometheus)')
    parser.add_argument('--no-nic', action='store_true',
                        help='Don\'t collect NIC info')
    parser.add_argument('--csv', type=str,
                        help='Output as CSV files in provided folder name')
    parser.add_argument('--emulators', action='store_true',
                        help='show emulators stats (implies --vm)')
    parser.add_argument('--balance', action='store_true',
                        help='Propose a way to balance load between nodes')
    parser.add_argument('--vm', action='store_true',
                        help='show vm stats')
    parser.add_argument('--node', type=str,
                        help='Limit to specific NUMA node (csv)')
    parser.add_argument('--vmexit', action='store_true',
                        help='show vm exit rates and reasons')
    parser.add_argument('--prometheus', nargs='?', const="localhost:8000",
                        help='enable the prometheus exporter, optionally specify host:port')
 
    args = parser.parse_args()

    if args.vcpu is True or args.emulators is True:
        args.vm = True
    if args.pid is not None:
        args.vm = True
        args.pids = []
        for i in args.pid.split(','):
            args.pids.append(int(i))
    # Sort mapping to variable name
    if args.sort == 'vcpu_util':
        args.sort = 'vcpu_sum_pc_util'
    elif args.sort == 'vcpu_steal':
        args.sort = 'vcpu_sum_pc_steal'
    elif args.sort == 'vhost_util':
        args.sort = 'vhost_sum_pc_util'
    elif args.sort == 'vhost_steal':
        args.sort = 'vhost_sum_pc_steal'
    elif args.sort == 'emulators_util':
        args.sort = 'emulators_sum_pc_util'
    elif args.sort == 'emulators_steal':
        args.sort = 'emulators_sum_pc_steal'
    elif args.sort == 'disk_read':
        args.sort = 'mb_read'
    elif args.sort == 'disk_write':
        args.sort = 'mb_write'
    elif args.sort == 'rx':
        args.sort = 'rx_rate'
    elif args.sort == 'tx':
        args.sort = 'tx_rate'
    elif args.sort == 'rx_dropped':
        args.sort = 'rx_rate_dropped'
    elif args.sort == 'tx_dropped':
        args.sort = 'tx_rate_dropped'

    # list of metrics we want to display by VM (needs to become user-definable)
    args.display_metrics = [
            'vcpu_sum_pc_util',
            'vcpu_sum_pc_steal',
            'vhost_sum_pc_util',
            'vhost_sum_pc_steal',
            'emulators_sum_pc_util',
            'emulators_sum_pc_steal',
            'mb_read',
            'mb_write',
            'rx_rate',
            'tx_rate',
            'rx_rate_dropped',
            'tx_rate_dropped',
            'last_vmexit_diff']
    # Format and legend for each metric
    args.vm_metrics = {'vcpu_sum_pc_util': ['vcpu', 'util%', '8s'],
                       'vcpu_sum_pc_steal': ['vcpu', 'steal%', '8s'],
                       'vhost_sum_pc_util': ['vhost', 'util%', '8s'],
                       'vhost_sum_pc_steal': ['vhost', 'steal%', '8s'],
                       'emulators_sum_pc_util': ['emu', 'util%', '8s'],
                       'emulators_sum_pc_steal': ['emu', 'steal%', '8s'],
                       'mb_read': ['disk', 'rd MB/s', '8s'],
                       'mb_write': ['disk', 'wr MB/s', '8s'],
                       'rx_rate': ['rx', 'MBps', '8s'],
                       'tx_rate': ['tx', 'MBps', '8s'],
                       'rx_rate_dropped': ['rx_drop', 'pkt/s', '8s'],
                       'tx_rate_dropped': ['tx_drop', 'pkt/s', '9s'],
                       'last_vmexit_diff': ['vmexit', 'count', '8s']}
    args.vm_format = '{:<19s}{:<8s}'
    for m in args.display_metrics:
        args.vm_format = "%s{:<%s}" % (args.vm_format, args.vm_metrics[m][2])

    # filter by node
    if args.node is not None:
        nodes = []
        for n in args.node.split(','):
            nodes.append(int(n))
        args.node = nodes

    if args.prometheus and import_failed_prometheus:
        print("Warning: python3-prometheus-client not found! Please install and re-run or remove --prometheus")
        exit(1)

    if args.daemon and import_failed_daemon:
        print("Warning: python3-daemon not found! Please install and re-run")
        exit(1)

    if args.vmexit and import_failed_bcc:
        print("Error: missing bcc library")
        exit(1)

    return args


def main():
    if os.geteuid() != 0:
        print("Need to run as root")
        return 1

    args = parse_args()
    signal.signal(signal.SIGTERM, exit_gracefully)
    signal.signal(signal.SIGINT, exit_gracefully)

    # Start prometheus
    # With daemon option, prometheus will be run after
    # daemonizing below
    if args.prometheus and not args.daemon:
            ip, port = args.prometheus.split(':')
            start_prometheus_client(ip, port)

    # Daemonize vmtop if --daemon option specificed
    # Supported with --csv and --prometheus flags
    if args.daemon and args.csv is not None or args.prometheus and args.daemon:
        cwd = os.getcwd()
        with daemon.DaemonContext(stdout=sys.stdout,
            stderr = sys.stdout,
            working_directory = cwd,
            umask = 0o002,
            signal_map={
            signal.SIGTERM: exit_gracefully
        }):
            # Daemonizing kills all the previously opened sockets, so
            # run prometheus after daemonizing
            if args.prometheus:
                ip, port = args.prometheus.split(':')
                start_prometheus_client(ip, port)

            s = VmTop(args)
            if args.number > 0:
                s.run(args.number)
            else:
                s.loop()

    else:
        s = VmTop(args)

        if args.number > 0:
            s.run(args.number)
        else:
            s.loop()

    return 0

if __name__ == '__main__':
    sys.exit(main())