From: Sascha Westermann via pve-devel <pve-devel@lists.proxmox.com>
To: pve-devel@lists.proxmox.com
Cc: Sascha Westermann <sascha.westermann@hl-services.de>
Subject: [pve-devel] [PATCH qemu-server 3/3] Fix #5708: Add CPU raw counters
Date: Tue, 17 Sep 2024 07:50:20 +0200 [thread overview]
Message-ID: <mailman.6.1726728980.332.pve-devel@lists.proxmox.com> (raw)
In-Reply-To: <20240917055020.10507-1-sascha.westermann@hl-services.de>
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From: Sascha Westermann <sascha.westermann@hl-services.de>
To: pve-devel@lists.proxmox.com
Cc: Sascha Westermann <sascha.westermann@hl-services.de>
Subject: [PATCH qemu-server 3/3] Fix #5708: Add CPU raw counters
Date: Tue, 17 Sep 2024 07:50:20 +0200
Message-ID: <20240917055020.10507-4-sascha.westermann@hl-services.de>
Add a map containing raw values from /proc/<pid>/stat (utime, stime and
guest_time), "uptime_ticks" and "user_hz" (from cpuinfo) to calcuate
physical CPU usage from two samples. In addition, virtual CPU statistics
based on /proc/<pid>/task/<tid>/schedstat (<tid> for virtual cores) are
added - based on this data, the CPU usage can be calculated from the
perspective of the virtual machine.
The total usage corresponds to "cpu_ns + runqueue_ns", "cpu_ns" should
roughly reflect the physical CPU usage (without I/O-threads and
emulators) and "runqueue_ns" corresponds to the value of %steal, i.e.
the same as "CPU ready" for VMware or "Wait for dispatch" for Hyper-V.
To calculate the difference value, uptime_ticks and user_hz would be
converted to nanoseconds - the value was determined immediately after
utime, stime and guest_time were determined from /proc/<pid>/stat, i.e.
before /proc/<pid>/task/<tid>/schedstat was determined. The time value
is therefore not exact, but should be sufficiently close to the time of
determination so that the values determined should be relatively
accurate.
Signed-off-by: Sascha Westermann <sascha.westermann@hl-services.de>
---
PVE/QemuServer.pm | 55 +++++++++++++++++++++++++++++++++++++++++++++--
1 file changed, 53 insertions(+), 2 deletions(-)
diff --git a/PVE/QemuServer.pm b/PVE/QemuServer.pm
index b26da505..39830709 100644
--- a/PVE/QemuServer.pm
+++ b/PVE/QemuServer.pm
@@ -2814,6 +2814,40 @@ our $vmstatus_return_properties = {
my $last_proc_pid_stat;
+sub get_vcpu_to_thread_id {
+ my ($pid) = @_;
+ my @cpu_to_thread_id;
+ my $task_dir = "/proc/$pid/task";
+
+ if (! -d $task_dir) {
+ return @cpu_to_thread_id;
+ }
+
+ opendir(my $dh, $task_dir);
+ if (!$dh) {
+ return @cpu_to_thread_id;
+ }
+ while (my $tid = readdir($dh)) {
+ next if $tid =~ /^\./;
+ my $comm_file = "$task_dir/$tid/comm";
+ next unless -f $comm_file;
+
+ open(my $fh, '<', $comm_file) or next;
+ my $comm = <$fh>;
+ close($fh);
+
+ chomp $comm;
+
+ if ($comm =~ /^CPU\s+(\d+)\/KVM$/) {
+ my $vcpu = $1;
+ push @cpu_to_thread_id, { tid => $tid, vcpu => $vcpu };
+ }
+ }
+ closedir($dh);
+
+ return @cpu_to_thread_id;
+}
+
# get VM status information
# This must be fast and should not block ($full == false)
# We only query KVM using QMP if $full == true (this can be slow)
@@ -2827,8 +2861,6 @@ sub vmstatus {
my $list = vzlist();
my $defaults = load_defaults();
- my ($uptime) = PVE::ProcFSTools::read_proc_uptime(1);
-
my $cpucount = $cpuinfo->{cpus} || 1;
foreach my $vmid (keys %$list) {
@@ -2911,6 +2943,25 @@ sub vmstatus {
my $pstat = PVE::ProcFSTools::read_proc_pid_stat($pid);
next if !$pstat; # not running
+ my ($uptime) = PVE::ProcFSTools::read_proc_uptime(1);
+ my $process_uptime_ticks = $uptime - $pstat->{starttime};
+
+ $d->{cpustat}->{guest_time} = int($pstat->{guest_time});
+ $d->{cpustat}->{process_uptime_ticks} = $process_uptime_ticks;
+ $d->{cpustat}->{stime} = int($pstat->{stime});
+ $d->{cpustat}->{user_hz} = $cpuinfo->{user_hz};
+ $d->{cpustat}->{utime} = int($pstat->{utime});
+
+ my @vcpu_to_thread_id = get_vcpu_to_thread_id($pid);
+ if (@vcpu_to_thread_id) {
+ foreach my $entry (@vcpu_to_thread_id) {
+ my $statstr = PVE::Tools::file_read_firstline("/proc/$pid/task/$entry->{tid}/schedstat") or next;
+ if ($statstr && $statstr =~ m/^(\d+) (\d+) \d/) {
+ $d->{cpustat}->{"vcpu" . $entry->{vcpu}}->{cpu_ns} = int($1);
+ $d->{cpustat}->{"vcpu" . $entry->{vcpu}}->{runqueue_ns} = int($2);
+ };
+ }
+ }
my $used = $pstat->{utime} + $pstat->{stime};
--
2.46.0
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prev parent reply other threads:[~2024-09-19 6:56 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20240917055020.10507-1-sascha.westermann@hl-services.de>
2024-09-17 5:50 ` [pve-devel] [PATCH pve-common 1/3] " Sascha Westermann via pve-devel
2024-09-17 5:50 ` [pve-devel] [PATCH pve-manager 2/3] " Sascha Westermann via pve-devel
2024-09-17 5:50 ` Sascha Westermann via pve-devel [this message]
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