From mboxrd@z Thu Jan 1 00:00:00 1970 Content-Type: multipart/mixed; boundary="===============0480222678334903547==" MIME-Version: 1.0 From: Sergey Senozhatsky Subject: Re: [Powertop] [PATCH 1/2] perf: Pass 0 as a third argument to ioctl on perf_fd Date: Mon, 17 Sep 2012 02:17:30 +0300 Message-ID: <20120916231730.GB3092@swordfish> In-Reply-To: 1347805051-2889-1-git-send-email-namhyung@gmail.com To: powertop@lists.01.org List-ID: --===============0480222678334903547== Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable On (09/16/12 23:17), Namhyung Kim wrote: > The third argument of PERF_EVENT_IOC_{ENABLE,DISABLE} ioctl is a flag > to determine whether the command should be applied to group members. > Since the powertop doesn't use the event grouping feature, it'd better > passing 0 as a third argument explicitly. > [..] <+629>: mov -0x88(%rbp),%rax <+636>: mov 0x8(%rax),%eax <+639>: mov $0x2400,%esi <+644>: mov %eax,%edi <+646>: mov $0x0,%eax <+651>: callq 0x404460 [..] agree, let's pass 0 explicitly to perf_ioctl(): 3307 3308 if (flags & PERF_IOC_FLAG_GROUP) 3309 perf_event_for_each(event, func); 3310 else 3311 perf_event_for_each_child(event, func); 3312 = good catch, thank you! -ss = > Signed-off-by: Namhyung Kim > --- > src/perf/perf.cpp | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > = > diff --git a/src/perf/perf.cpp b/src/perf/perf.cpp > index 69f1da3..c8ba7a8 100644 > --- a/src/perf/perf.cpp > +++ b/src/perf/perf.cpp > @@ -128,7 +128,7 @@ void perf_event::create_perf_event(char *eventname, i= nt _cpu) > return; > } > = > - ret =3D ioctl(perf_fd, PERF_EVENT_IOC_ENABLE); > + ret =3D ioctl(perf_fd, PERF_EVENT_IOC_ENABLE, 0); > = > if (ret < 0) { > fprintf(stderr, "failed to enable perf \n"); > @@ -210,7 +210,7 @@ void perf_event::start(void) > void perf_event::stop(void) > { > int ret; > - ret =3D ioctl(perf_fd, PERF_EVENT_IOC_DISABLE); > + ret =3D ioctl(perf_fd, PERF_EVENT_IOC_DISABLE, 0); > if (ret) > cout << "stop failing\n"; > } >=20 --===============0480222678334903547==--