Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751448AbaLQC3b (ORCPT ); Tue, 16 Dec 2014 21:29:31 -0500 Received: from mail-ob0-f178.google.com ([209.85.214.178]:43435 "EHLO mail-ob0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751066AbaLQC3a (ORCPT ); Tue, 16 Dec 2014 21:29:30 -0500 MIME-Version: 1.0 Reply-To: eranian@gmail.com In-Reply-To: <5490E856.6050904@huawei.com> References: <20141215220150.GP9845@kernel.org> <5490E856.6050904@huawei.com> Date: Wed, 17 Dec 2014 03:29:29 +0100 Message-ID: Subject: Re: [perf tool] cgroup support broken on Debian? From: Stephane Eranian To: Zefan Li Cc: Vince Weaver , Arnaldo Carvalho de Melo , LKML , Ingo Molnar , Peter Zijlstra , Stephane Eranian , Tejun Heo Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Dec 17, 2014 at 3:20 AM, Zefan Li wrote: > On 2014/12/17 1:17, Vince Weaver wrote: >> On Mon, 15 Dec 2014, Stephane Eranian wrote: >>> On Mon, Dec 15, 2014 at 11:01 PM, Arnaldo Carvalho de Melo wrote: >> >>> fs is visible. The cgroup file system type is not there anymore. They are using >>> tmpfs which is not ideal to detect just cgroup. Looks like now, we have to look >>> at the mount point which is flaky. >> >> The trivial fix is to just always assume things will be under >> /sys/fs/cgroup >> which looks like to be the new official mount point. >> >> This will break on older systems though, or systems that mount cgroupfs in >> multiple locations. >> >> Another alternative is to change the interface to require the full >> cgroupfs pathname as an argument to -G >> > > What's the problem here? > > none /sys/fs/cgroup tmpfs rw,relatime,size=4k,mode=755 0 0 > systemd /sys/fs/cgroup/systemd cgroup rw,nosuid,nodev,noexec,relatime,perf_event,name=systemd 0 0 > > cgroup is mounted in /sys/fs/cgroup/systemd, so you should pass '/' to the -G argument: > Is that the only mountpoint possible? The tool needs to detect a valid mount point to locate the named cgroup. That's assuming that if I create cgroup foo, then it appears under //sys/fs/cgroup/systemd/foo > sudo perf stat -a -e cycles:u,cycles:u,cycles:u -G / -- sleep 1 > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/