[pve-devel] [PATCH 3/5] fix #3593: Added vm core pinning qemu-server

[Matthias Heiserer]

I'm not sure where it comes from, but when starting a VM, the task log 
receives a bunch of messages on changed affinity:

pid 95121's current affinity list: 0-7
pid 95121's new affinity list: 2,3
pid 95122's current affinity list: 0-7
pid 95122's new affinity list: 2,3
pid 95123's current affinity list: 0-7
pid 95123's new affinity list: 2,3
pid 95184's current affinity list: 0-7
pid 95184's new affinity list: 2,3
pid 95185's current affinity list: 0-7
pid 95185's new affinity list: 2,3
pid 95187's current affinity list: 0-7
pid 95187's new affinity list: 2,3

Can we avoid showing them? I don't think they offer any insight, because 
as I understand it, when starting, the current affinity list is always 
all available cores.

On 08.06.2022 13:54, Daniel Bowder wrote:
> Signed-off-by: Daniel Bowder <daniel at bowdernet.com>
> ---
>   The third patch adds cpuset as a valid object in the qm conf file. A new type is created called 'pve-cpuset' so that the cpuset can go through some validation before passing it to the taskset command. The exec_taskset command is executed just after the 'post-start' hookscript, which ensures that there is a valid PID to pin.
The commit message should be above the lines :)
Otherwise, it won't be part of the commit, but only a comment visible on 
the mailing list.
>   PVE/QemuServer.pm | 49 +++++++++++++++++++++++++++++++++++++++++++++++
>   1 file changed, 49 insertions(+)
> 
> diff --git a/PVE/QemuServer.pm b/PVE/QemuServer.pm
> index e9aa248..6b9abc0 100644
> --- a/PVE/QemuServer.pm
> +++ b/PVE/QemuServer.pm
> @@ -713,6 +713,11 @@ EODESCR
>   	description => "Some (read-only) meta-information about this guest.",
>   	optional => 1,
>       },
> +	cpuset => {
> +	type => 'string', format => 'pve-cpuset',
> +	description => "Specifies the cpu core numbers to pin the vm qemu processes to with 'taskset'.",
> +	optional => 1,
> +	},
>   };
>   
>   my $cicustom_fmt = {
> @@ -5802,6 +5807,8 @@ sub vm_start_nolock {
>   
>       PVE::GuestHelpers::exec_hookscript($conf, $vmid, 'post-start');
>   
> +    PVE::GuestHelpers::exec_taskset($conf, $vmid);
> +
>       return $res;
>   }
>   
> @@ -8214,4 +8221,46 @@ sub check_volume_storage_type {
>       return 1;
>   }
>   
> +sub parse_cpuset {
> +    my ($data) = @_;
> +
> +    my $res = "";
> +
> +	# Parse cpuset value
> +	foreach my $value (PVE::Tools::split_list($data)) {
> +		if ($value =~ m/^([0-9]+)-([0-9]+)$/) {
> +			if (int($1) > int($2)) {
> +				die "invalid cpuset value '$value', left value must be <= right\n";
> +			}
> +			my @range = (int($1) .. int($2));
> +			for my $cpu (@range) {
> +				$res .= "," . $cpu;
> +			}
> +		} elsif ($value =~ m/^([0-9]+)$/) {
> +			$res .= "," . $1;
> +		} else {
> +			die "invalid cpuset value '$value'\n";
> +		}
> +	}
> +
> +	if (!$res) {
> +		die "invalid cpuset '$data'\n";
> +	}
> +
> +	# Trim leading ","
> +    $res = substr($res, 1);
> +    return $res;
> +}
> +
> +PVE::JSONSchema::register_format('pve-cpuset', \&pve_verify_cpuset);
> +sub pve_verify_cpuset {
> +    my ($value, $noerr) = @_;
> +
> +    return $value if parse_cpuset($value);
> +
> +    return if $noerr;
> +
> +    die "unable to parse cpuset option\n";
> +}
> +
>   1;

BTW, my colleagues will also review your code at some point, so be 
prepared that there might be some more required changes