enable x2apic by default for kvm machines

This reduce context switch with multicore guests.

Even if the host cpu don't have x2apic, it's working because qemu have an virtual x2apic implementation for guest.
We need  in-kernel irqchip support for this, which is enable for kvm guest since qemu 1.3.
(I don't enable it if nokvm param is set)

Signed-off-by: Alexandre Derumier <aderumier@odiso.com>

diff --git a/PVE/QemuServer.pm b/PVE/QemuServer.pm
index 31d8103b689c928a1d9eb79ff602421926686aff..f0a3c01ea09815d46e8098e0419ea866b6ef7894 100644 (file)
--- a/PVE/QemuServer.pm
+++ b/PVE/QemuServer.pm
@@ -2225,6 +2225,7 @@ sub config_to_command {
     my $globalFlags = [];
     my $machineFlags = [];
     my $rtcFlags = [];
+    my $cpuFlags = [];
     my $devices = [];
     my $pciaddr = '';
     my $bridges = {};
@@ -2318,11 +2319,8 @@ sub config_to_command {
     $sockets = $conf->{sockets} if  $conf->{sockets};
 
     my $cores = $conf->{cores} || 1;
-
     push @$cmd, '-smp', "sockets=$sockets,cores=$cores";
 
-    push @$cmd, '-cpu', $conf->{cpu} if $conf->{cpu};
-
     push @$cmd, '-nodefaults';
 
     my $bootorder = $conf->{boot} || $confdesc->{boot}->{default};
@@ -2395,6 +2393,15 @@ sub config_to_command {
        push @$rtcFlags, 'base=localtime';
     }
 
+    my $cpu = $nokvm ? "qemu64" : "kvm64";
+    $cpu = $conf->{cpu} if $conf->{cpu};
+
+    push @$cpuFlags , '+x2apic' if !$nokvm;
+
+    $cpu .= ",".join(',', @$cpuFlags) if scalar(@$cpuFlags);
+
+    push @$cmd, '-cpu', $cpu;
+
     push @$cmd, '-S' if $conf->{freeze};
 
     # set keyboard layout
@@ -2423,7 +2430,6 @@ sub config_to_command {
        #$x509 .= ",x509-cacert-file=/etc/pve/pve-root-ca.pem";
 
        my $socket = spice_socket($vmid);
-
        push @$cmd, '-spice', "unix=$socket";
        push @$cmd, '-device', "virtio-serial,id=spice$pciaddr";
        push @$cmd, '-chardev', "spicevmc,id=vdagent,name=vdagent";