The VIR_DOMAIN_STATS_VCPU flag to virDomainListGetStats enables reporting of stats about vCPUs. Currently we only report the cumulative CPU running time and the execution state. This adds reporting of the wait time - time the vCPU wants to run, but the host schedular has something else running ahead of it. The data is reported per-vCPU eg $ virsh domstats --vcpu demo Domain: 'demo' vcpu.current=4 vcpu.maximum=4 vcpu.0.state=1 vcpu.0.time=1420000000 vcpu.0.wait=18403928 vcpu.1.state=1 vcpu.1.time=130000000 vcpu.1.wait=10612111 vcpu.2.state=1 vcpu.2.time=110000000 vcpu.2.wait=12759501 vcpu.3.state=1 vcpu.3.time=90000000 vcpu.3.wait=21825087 In implementing this I notice our reporting of CPU execute time has very poor granularity, since we are getting it from /proc/$PID/stat. As a future enhancement we should prefer to get CPU execute time from /proc/$PID/schedstat or /proc/$PID/sched (if either exist on the running kernel) Signed-off-by: Daniel P. Berrange <berrange@redhat.com> --- src/qemu/qemu_driver.c | 100 +++++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 96 insertions(+), 4 deletions(-) diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c index 36fb047..40c52d4 100644 --- a/src/qemu/qemu_driver.c +++ b/src/qemu/qemu_driver.c @@ -1361,6 +1361,80 @@ static char *qemuConnectGetCapabilities(virConnectPtr conn) { static int +qemuGetSchedInfo(unsigned long long *cpuWait, + pid_t pid, pid_t tid) +{ + char *proc = NULL; + char *data = NULL; + char **lines = NULL; + size_t i; + int ret = -1; + double val; + + *cpuWait = 0; + + /* In general, we cannot assume pid_t fits in int; but /proc parsing + * is specific to Linux where int works fine. */ + if (tid) + ret = virAsprintf(&proc, "/proc/%d/task/%d/sched", (int)pid, (int)tid); + else + ret = virAsprintf(&proc, "/proc/%d/sched", (int)pid); + if (ret < 0) + goto cleanup; + ret = -1; + + /* The file is not guaranteed to exist (needs CONFIG_SCHED_DEBUG) */ + if (access(proc, R_OK) < 0) + return 0; + + if (virFileReadAll(proc, (1<<16), &data) < 0) + goto cleanup; + + lines = virStringSplit(data, "\n", 0); + if (!lines) + goto cleanup; + + for (i = 0; lines[i] != NULL; i++) { + const char *line = lines[i]; + + /* Needs CONFIG_SCHEDSTATS. The second check + * is the old name the kernel used in past */ + if (STRPREFIX(line, "se.statistics.wait_sum") || + STRPREFIX(line, "se.wait_sum")) { + line = strchr(line, ':'); + if (!line) { + virReportError(VIR_ERR_INTERNAL_ERROR, + _("Missing separate in sched info '%s'"), + lines[i]); + goto cleanup; + } + line++; + while (*line == ' ') + line++; + + if (virStrToDouble(line, NULL, &val) < 0) { + virReportError(VIR_ERR_INTERNAL_ERROR, + _("Unable to parse sched info value '%s'"), + line); + goto cleanup; + } + + *cpuWait = (unsigned long long)(val * 1000000); + break; + } + } + + ret = 0; + + cleanup: + VIR_FREE(data); + VIR_FREE(proc); + VIR_FREE(lines); + return ret; +} + + +static int qemuGetProcessInfo(unsigned long long *cpuTime, int *lastCpu, long *vm_rss, pid_t pid, int tid) { @@ -1424,6 +1498,7 @@ qemuGetProcessInfo(unsigned long long *cpuTime, int *lastCpu, long *vm_rss, static int qemuDomainHelperGetVcpus(virDomainObjPtr vm, virVcpuInfoPtr info, + unsigned long long *cpuwait, int maxinfo, unsigned char *cpumaps, int maplen) @@ -1476,6 +1551,11 @@ qemuDomainHelperGetVcpus(virDomainObjPtr vm, virBitmapFree(map); } + if (cpuwait) { + if (qemuGetSchedInfo(&(cpuwait[i]), vm->pid, vcpupid) < 0) + return -1; + } + ncpuinfo++; } @@ -5490,7 +5570,7 @@ qemuDomainGetVcpus(virDomainPtr dom, goto cleanup; } - ret = qemuDomainHelperGetVcpus(vm, info, maxinfo, cpumaps, maplen); + ret = qemuDomainHelperGetVcpus(vm, info, NULL, maxinfo, cpumaps, maplen); cleanup: virDomainObjEndAPI(&vm); @@ -19036,6 +19116,7 @@ qemuDomainGetStatsVcpu(virQEMUDriverPtr driver ATTRIBUTE_UNUSED, int ret = -1; char param_name[VIR_TYPED_PARAM_FIELD_LENGTH]; virVcpuInfoPtr cpuinfo = NULL; + unsigned long long *cpuwait = NULL; if (virTypedParamsAddUInt(&record->params, &record->nparams, @@ -19051,10 +19132,12 @@ qemuDomainGetStatsVcpu(virQEMUDriverPtr driver ATTRIBUTE_UNUSED, virDomainDefGetVcpusMax(dom->def)) < 0) return -1; - if (VIR_ALLOC_N(cpuinfo, virDomainDefGetVcpus(dom->def)) < 0) - return -1; + if (VIR_ALLOC_N(cpuinfo, virDomainDefGetVcpus(dom->def)) < 0 || + VIR_ALLOC_N(cpuwait, virDomainDefGetVcpus(dom->def)) < 0) + goto cleanup; - if (qemuDomainHelperGetVcpus(dom, cpuinfo, virDomainDefGetVcpus(dom->def), + if (qemuDomainHelperGetVcpus(dom, cpuinfo, cpuwait, + virDomainDefGetVcpus(dom->def), NULL, 0) < 0) { virResetLastError(); ret = 0; /* it's ok to be silent and go ahead */ @@ -19083,12 +19166,21 @@ qemuDomainGetStatsVcpu(virQEMUDriverPtr driver ATTRIBUTE_UNUSED, param_name, cpuinfo[i].cpuTime) < 0) goto cleanup; + snprintf(param_name, VIR_TYPED_PARAM_FIELD_LENGTH, + "vcpu.%zu.wait", i); + if (virTypedParamsAddULLong(&record->params, + &record->nparams, + maxparams, + param_name, + cpuwait[i]) < 0) + goto cleanup; } ret = 0; cleanup: VIR_FREE(cpuinfo); + VIR_FREE(cpuwait); return ret; } -- 2.5.0