[pve-devel] [PATCH 2/5] fix #3593: Added vm core pinning pve-guest-common

[Daniel Bowder <daniel@bowdernet.com>]

Signed-off-by: Daniel Bowder <daniel@bowdernet.com>
---
 The second patch adds a utility function to obtain the pid of the VM, then calls taskset on that pid with the cpuset in the qm conf. This execution of taskset pins the VMs process to the defined cpu cores. This utility function acts similarly to the exec_hookscript utility function. In fact, in the third patch this utility function will be called just after the "post-start" call to hookscript.
 src/PVE/GuestHelpers.pm | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/src/PVE/GuestHelpers.pm b/src/PVE/GuestHelpers.pm
index 0fe3fd6..a8f54fa 100644
--- a/src/PVE/GuestHelpers.pm
+++ b/src/PVE/GuestHelpers.pm
@@ -82,6 +82,30 @@ sub guest_migration_lock {
     return $res;
 }
 
+sub exec_taskset {
+	my ($conf, $vmid) = @_;
+
+	return if !$conf->{cpuset};
+
+	eval {
+		# Obtain the vm PID from /run/qemu-server/$vmid.pid
+		PVE::Tools::run_command(
+			[ "cat", "/run/qemu-server/$vmid.pid" ],
+			outfunc => sub {
+				my $line = shift;
+				if ($line =~ m/^([0-9]+)$/) {
+					# Pin the PID to the cpuset
+					PVE::Tools::run_command(
+						[ "taskset", "--cpu-list", "--all-tasks", "--pid", $conf->{cpuset}, $1 ]
+					);
+				} else {
+					warn "cpuset error: failed to obtain vm process id.\n";
+				}
+			}
+		);
+	};
+}
+
 sub check_hookscript {
     my ($volid, $storecfg) = @_;
 
-- 
2.30.2