Re: [libvirt] [PATCH v2.1 11/21] Add qemuProcessSetEmulatorAffinites and set emulator threads affinities

From: Tang Chen <tangchen(a)cn.fujitsu.com&gt; Emulator threads should also be pinned by sched_setaffinity(), just the same as vcpu threads. Signed-off-by: Tang Chen <tangchen(a)cn.fujitsu.com&gt; Signed-off-by: Hu Tao <hutao(a)cn.fujitsu.com&gt; --- src/qemu/qemu_process.c | 54 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 54 insertions(+) diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c index 762f298..90d44c4 100644 --- a/src/qemu/qemu_process.c +++ b/src/qemu/qemu_process.c @@ -2002,6 +2002,56 @@ cleanup: return ret; } +/* Set CPU affinities for emulator threads if emulatorpin xml provided. */ +static int +qemuProcessSetEmulatorAffinites(virConnectPtr conn, + virDomainObjPtr vm) +{ + virDomainDefPtr def = vm->def; + pid_t pid = vm->pid; + unsigned char *cpumask = NULL; + unsigned char *cpumap = NULL; + virNodeInfo nodeinfo; + int cpumaplen, hostcpus, maxcpu, i; + int ret = -1; + + if (virNodeGetInfo(conn, &nodeinfo) != 0) + return -1; + + if (!def->cputune.emulatorpin) + return 0; + + hostcpus = VIR_NODEINFO_MAXCPUS(nodeinfo); + cpumaplen = VIR_CPU_MAPLEN(hostcpus); + maxcpu = cpumaplen * CHAR_BIT; + + if (maxcpu > hostcpus) + maxcpu = hostcpus; + + if (VIR_ALLOC_N(cpumap, cpumaplen) < 0) { + virReportOOMError(); + return -1; + } + + cpumask = (unsigned char *)def->cputune.emulatorpin->cpumask; + for(i = 0; i < VIR_DOMAIN_CPUMASK_LEN; i++) {

+ if (cpumask[i]) + VIR_USE_CPU(cpumap, i); + } + + if (virProcessInfoSetAffinity(pid, + cpumap, + cpumaplen, + maxcpu) < 0) { + goto cleanup; + } + + ret = 0; +cleanup: + VIR_FREE(cpumap); + return ret; +} + static int qemuProcessInitPasswords(virConnectPtr conn, struct qemud_driver *driver, @@ -3764,6 +3814,10 @@ int qemuProcessStart(virConnectPtr conn, if (qemuProcessSetVcpuAffinites(conn, vm) < 0) goto cleanup; + VIR_DEBUG("Setting affinity of emulator threads"); + if (qemuProcessSetEmulatorAffinites(conn, vm) < 0) + goto cleanup; + VIR_DEBUG("Setting any required VM passwords"); if (qemuProcessInitPasswords(conn, driver, vm) < 0) goto cleanup;