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

diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c index 783a7cd..5293294 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; +

+ /* 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++; + }