From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753112Ab0KZBsw (ORCPT ); Thu, 25 Nov 2010 20:48:52 -0500 Received: from cn.fujitsu.com ([222.73.24.84]:61267 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1752950Ab0KZBsv (ORCPT ); Thu, 25 Nov 2010 20:48:51 -0500 Message-ID: <4CEF1260.4000009@cn.fujitsu.com> Date: Fri, 26 Nov 2010 09:50:24 +0800 From: Li Zefan User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.1b3pre) Gecko/20090513 Fedora/3.0-2.3.beta2.fc11 Thunderbird/3.0b2 MIME-Version: 1.0 To: Peter Zijlstra CC: eranian@google.com, linux-kernel@vger.kernel.org, mingo@elte.hu, paulus@samba.org, davem@davemloft.net, fweisbec@gmail.com, perfmon2-devel@lists.sf.net, eranian@gmail.com, robert.richter@amd.com, acme@redhat.com, Paul Menage , Balbir Singh , Greg Kroah-Hartman Subject: Re: [PATCH 1/2] perf_events: add support for per-cpu per-cgroup monitoring (v5) References: <4ce510d4.0fedd80a.742c.10b9@mx.google.com> <1290684523.2145.31.camel@laptop> In-Reply-To: <1290684523.2145.31.camel@laptop> X-MIMETrack: Itemize by SMTP Server on mailserver/fnst(Release 8.5.1FP4|July 25, 2010) at 2010-11-26 09:49:00, Serialize by Router on mailserver/fnst(Release 8.5.1FP4|July 25, 2010) at 2010-11-26 09:49:03, Serialize complete at 2010-11-26 09:49:03 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 19:28, Peter Zijlstra wrote: > On Thu, 2010-11-18 at 12:40 +0200, Stephane Eranian wrote: >> This kernel patch adds the ability to filter monitoring based on >> container groups (cgroups). This is for use in per-cpu mode only. >> >> The cgroup to monitor is passed as a file descriptor in the pid >> argument to the syscall. The file descriptor must be opened to >> the cgroup name in the cgroup filesystem. For instance, if the >> cgroup name is foo and cgroupfs is mounted in /cgroup, then the >> file descriptor is opened to /cgroup/foo. Cgroup mode is >> activated by passing PERF_FLAG_PID_CGROUP in the flags argument >> to the syscall. >> >> For instance to measure in cgroup foo on CPU1 assuming >> cgroupfs is mounted under /cgroup: >> >> struct perf_event_attr attr; >> int cgroup_fd, fd; >> >> cgroup_fd = open("/cgroup/foo", O_RDONLY); >> fd = perf_event_open(&attr, cgroup_fd, 1, -1, PERF_FLAG_PID_CGROUP); >> close(cgroup_fd); >> >> Signed-off-by: Stephane Eranian > > Could you please split this patch: > - pure code movement > - time accounting changes > - event_filter_match() stuff > - cgroup thing > > From a quick reading it doesn't look bad, but I want an ACK from the > cgroup people -- specifically if they're OK with the filedesc juggling > thing, because I know the sysfs people objected to such tricks. > Long long ago, a feature that used this trick was accepted, and that's cgroup taskstat. You get an fd of a cgroup directory and send it to the kernel via netlink, and then you'll receive some statistics, such as how many tasks are running/interrupted in that cgroup. > Also, it might make sense to add a CONFIG_PERF_CGROUP, even if you want > it automagically set if CONFIG_PERF && CONFIG_CGROUP, its easier to find > all related code if its under a single CONFIG_var. >