-----Original Message----- From: Daniel P. Berrange [mailto:berrange@redhat.com] Sent: Tuesday, December 8, 2015 6:54 PM To: Ren, Qiaowei Cc: libvir-list@redhat.com; Jiri Denemark Subject: Re: [PATCH v2 3/8] perf: implement a set of util functions for perf event
On Mon, Dec 07, 2015 at 03:53:54PM +0800, Qiaowei Ren wrote:
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@intel.com> --- 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
+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; + }
Since we're closing the file handle next, is there any benefit in doing this ioctl() ?
I guess that VIR_FORCE_CLOSE() will just close the file handle, but the perf event have to be disabled before this. In fact it is from the example in man page of perf_event_open(). Thanks, Qiaowei