Re: [pve-devel] [PATCH pve-container] pct: fix cpu load calculation on command line

[Philipp Hufnagl <p.hufnagl@proxmox.com>]

Sorry forgott to tag as v2

On 7/18/23 13:58, Philipp Hufnagl wrote:
>   When called from the command line, it was not possible to calculate
>   cpu load because there was no 2nd data point available for the
>   calculation. Now (when called) from the command line, cpu stats will
>   be fetched twice with a minimum delta of 20ms. That way the load can
>   be calculated
>
> fixes #4765
>
> Signed-off-by: Philipp Hufnagl <p.hufnagl@proxmox.com>
> ---
>   src/PVE/CLI/pct.pm |  4 ++--
>   src/PVE/LXC.pm     | 32 +++++++++++++++++++++++++++++---
>   2 files changed, 31 insertions(+), 5 deletions(-)
>
> diff --git a/src/PVE/CLI/pct.pm b/src/PVE/CLI/pct.pm
> index ff75d33..e531b27 100755
> --- a/src/PVE/CLI/pct.pm
> +++ b/src/PVE/CLI/pct.pm
> @@ -60,8 +60,8 @@ __PACKAGE__->register_method ({
>   
>   	# test if CT exists
>   	my $conf = PVE::LXC::Config->load_config ($param->{vmid});
> -
> -	my $vmstatus = PVE::LXC::vmstatus($param->{vmid});
> +	# workaround to get cpu usage is to fetch cpu stats twice with a delay
> +	my $vmstatus = PVE::LXC::vmstatus($param->{vmid}, 20);
>   	my $stat = $vmstatus->{$param->{vmid}};
>   	if ($param->{verbose}) {
>   	    foreach my $k (sort (keys %$stat)) {
> diff --git a/src/PVE/LXC.pm b/src/PVE/LXC.pm
> index a531ea5..9fc171f 100644
> --- a/src/PVE/LXC.pm
> +++ b/src/PVE/LXC.pm
> @@ -12,7 +12,7 @@ use IO::Poll qw(POLLIN POLLHUP);
>   use IO::Socket::UNIX;
>   use POSIX qw(EINTR);
>   use Socket;
> -use Time::HiRes qw (gettimeofday);
> +use Time::HiRes qw (gettimeofday usleep);
>   
>   use PVE::AccessControl;
>   use PVE::CGroup;
> @@ -171,11 +171,37 @@ our $vmstatus_return_properties = {
>       }
>   };
>   
> +sub get_first_cpu {
> +    my ($list, $measure_timespan_ms) = @_;
> +    my $cdtime = gettimeofday;
> +
> +    foreach my $vmid (keys %$list) {
> +	my $cgroups = PVE::LXC::CGroup->new($vmid);
> +	if (defined(my $cpu = $cgroups->get_cpu_stat())) {
> +	    # Total time (in milliseconds) used up by the cpu.
> +	    my $used_ms = $cpu->{utime} + $cpu->{stime};
> +	    $last_proc_vmid_stat->{$vmid} = {
> +		time => $cdtime,
> +		used => $used_ms,
> +		cpu => 0,
> +	    };
> +	}
> +    }
> +    usleep($measure_timespan_ms * 1000);
> +}
> +
>   sub vmstatus {
> -    my ($opt_vmid) = @_;
> +    my ($opt_vmid, $measure_timespan_ms) = @_;
>   
>       my $list = $opt_vmid ? { $opt_vmid => { type => 'lxc', vmid => int($opt_vmid) }} : config_list();
>   
> +    if (defined($measure_timespan_ms))
> +    {
> +	get_first_cpu($list, $measure_timespan_ms);
> +    }
> +
> +    $measure_timespan_ms //= 1000;
> +
>       my $active_hash = list_active_containers();
>   
>       my $cpucount = $cpuinfo->{cpus} || 1;
> @@ -285,7 +311,7 @@ sub vmstatus {
>   	    }
>   
>   	    my $delta_ms = ($cdtime - $old->{time}) * $cpucount * 1000.0;
> -	    if ($delta_ms > 1000.0) {
> +	    if ($delta_ms > $measure_timespan_ms) {
>   		my $delta_used_ms = $used_ms - $old->{used};
>   		$d->{cpu} = (($delta_used_ms / $delta_ms) * $cpucount) / $d->{cpus};
>   		$last_proc_vmid_stat->{$vmid} = {