Re: [libvirt] [PATCH v2] qemu: add reporting of vCPU wait time

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.

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 + 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; + }