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

-----Original Message----- From: Daniel P. Berrange [mailto:berrange@redhat.com] Sent: Tuesday, December 8, 2015 6:54 PM To: Ren, Qiaowei Cc: libvir-list(a)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(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 > > +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() ?