Re: [libvirt] [PATCH v2 3/8] perf: implement a set of util functions for perf event

This patch implement a set of interfaces for perf event. Based on these interfaces, we can implement internal driver API for perf, and get the results of perf conuter you care about. Signed-off-by: Qiaowei Ren <qiaowei.ren(a)intel.com&gt; --- include/libvirt/virterror.h | 1 + src/Makefile.am | 1 + src/libvirt_private.syms | 12 ++ src/util/virerror.c | 1 + src/util/virperf.c | 298 ++++++++++++++++++++++++++++++++++++++++++++ src/util/virperf.h | 61 +++++++++ 6 files changed, 374 insertions(+) create mode 100644 src/util/virperf.c create mode 100644 src/util/virperf.h

+VIR_ENUM_IMPL(virPerfEvent, VIR_PERF_EVENT_LAST, + "cmt"); + +struct virPerfEvent { + int type; + int fd; + bool enabled; + union { + /* cmt */ + struct { + int scale; + } cmt; + } efields; +}; +typedef struct virPerfEvent *virPerfEventPtr; + +struct virPerf { + struct virPerfEvent events[VIR_PERF_EVENT_LAST]; +}; + +virPerfPtr +virPerfNew(void) +{ + size_t i; + virPerfPtr perf; + + if (VIR_ALLOC(perf) < 0) + return NULL; + + for (i = 0; i < VIR_PERF_EVENT_LAST; i++) { + perf->events[i].type = i; + perf->events[i].fd = -1; + perf->events[i].enabled = false; + } + + return perf; +} + +void +virPerfFree(virPerfPtr perf) +{ + size_t i; + + if (perf == NULL) + return; + + for (i = 0; i < VIR_PERF_EVENT_LAST; i++) { + if (perf->events[i].enabled) + virPerfEventDisable(perf, i); + } + + VIR_FREE(perf); +} + +#if defined(__linux__) && defined(HAVE_SYS_SYSCALL_H) + +# include <linux/perf_event.h> + +static virPerfEventPtr +virPerfGetEvent(virPerfPtr perf, + virPerfEventType type) +{ + if (type >= VIR_PERF_EVENT_LAST) { + virReportError(VIR_ERR_INTERNAL_ERROR, + _("Event '%d' is not supported"), + type); + return NULL; + } + + return perf->events + type; +} + +static int +virPerfCmtEnable(virPerfEventPtr event, + pid_t pid) +{ + struct perf_event_attr cmt_attr; + int event_type; + FILE *fp = NULL; + FILE *fp_scale = NULL; + int scale = 0; + + fp = fopen("/sys/devices/intel_cqm/type", "r"); + if (!fp) { + virReportSystemError(errno, "%s", + _("CMT is not available on this host")); + return -1; + } + if (fscanf(fp, "%d", &event_type) != 1) { + virReportSystemError(errno, "%s", + _("Unable to read event type file.")); + goto cleanup; + }

+ + fp_scale = fopen("/sys/devices/intel_cqm/events/llc_occupancy.scale", "r"); + if (!fp_scale) { + virReportSystemError(errno, "%s", + _("Unable to open CMT scale file")); + goto cleanup; + } + if (fscanf(fp_scale, "%d", &scale) != 1) { + virReportSystemError(errno, "%s", + _("Unable to read CMT scale file")); + goto cleanup; + }

+ event->efields.cmt.scale = scale; + + memset(&cmt_attr, 0, sizeof(cmt_attr)); + cmt_attr.size = sizeof(cmt_attr); + cmt_attr.type = event_type; + cmt_attr.config = 1; + cmt_attr.inherit = 1; + cmt_attr.disabled = 1; + cmt_attr.enable_on_exec = 0; + + event->fd = syscall(__NR_perf_event_open, &cmt_attr, pid, -1, -1, 0); + if (event->fd < 0) { + virReportSystemError(errno, + _("Unable to open perf type=%d for pid=%d"), + event_type, pid); + goto cleanup; + } + + if (ioctl(event->fd, PERF_EVENT_IOC_ENABLE) < 0) { + virReportSystemError(errno, "%s", + _("Unable to enable perf event for CMT")); + goto cleanup; + } + + event->enabled = true; + return 0; + + cleanup: + if (fp) + VIR_FORCE_FCLOSE(fp); + if (fp_scale) + VIR_FORCE_FCLOSE(fp_scale); + if (event->fd >= 0) + VIR_FORCE_CLOSE(event->fd); + return -1;

+int +virPerfEventDisable(virPerfPtr perf, + virPerfEventType type) +{ + virPerfEventPtr event = virPerfGetEvent(perf, type); + if (event == NULL) + return -1; + + if (ioctl(event->fd, PERF_EVENT_IOC_DISABLE) < 0) { + virReportSystemError(errno, + _("Unable to disable perf event type=%d"), + event->type); + return -1; + }

+ + event->enabled = false; + VIR_FORCE_CLOSE(event->fd); + return 0; +}