From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756526Ab3BDQ2b (ORCPT ); Mon, 4 Feb 2013 11:28:31 -0500 Received: from e34.co.us.ibm.com ([32.97.110.152]:39811 "EHLO e34.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756405Ab3BDQ2a (ORCPT ); Mon, 4 Feb 2013 11:28:30 -0500 Date: Mon, 4 Feb 2013 21:56:11 +0530 From: Srikar Dronamraju To: Oleg Nesterov , Steven Rostedt , Masami Hiramatsu Cc: Ingo Molnar , Anton Arapov , Frank Eigler , Josh Stone , "Suzuki K. Poulose" , linux-kernel@vger.kernel.org Subject: Re: [PATCH 6/6] uprobes/perf: Always increment trace_uprobe->nhit Message-ID: <20130204162611.GB28145@linux.vnet.ibm.com> Reply-To: Srikar Dronamraju References: <20130131191752.GA30410@redhat.com> <20130131191832.GA30457@redhat.com> <20130204111711.GB12900@linux.vnet.ibm.com> <20130204151850.GA6641@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: <20130204151850.GA6641@redhat.com> User-Agent: Mutt/1.5.20 (2009-06-14) X-Content-Scanned: Fidelis XPS MAILER x-cbid: 13020416-2876-0000-0000-000004E2D894 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Oleg Nesterov [2013-02-04 16:18:50]: > On 02/04, Srikar Dronamraju wrote: > > > > * Oleg Nesterov [2013-01-31 20:18:32]: > > > > > Move tu->nhit++ from uprobe_trace_func() to uprobe_dispatcher(). > > > > > > ->nhit counts how many time we hit the breakpoint inserted by this > > > uprobe, we do not want to loose this info if uprobe was enabled by > > > sys_perf_event_open(). > > > > > > > Though I dont see a problem with this change, It seems unnecessary for > > me. > > > > Info from nhits is mostly for /sys/kernel/debug/tracing/uprobe_profile > > It is only for uprobe_profile, yes, and it is useful. Why should we hide > this info if this uprobe is used by perf? Fine with me. Steve, Masami, Do you have comments/suggestions on this. (Since kprobe_profile just accounts for kprobetracer and doesnt account for perf record.) May we should make a similar change in kprobetracer to keep things similar. -- Thanks and Regards Srikar Dronamraju > > > I am not sure how sys_perf_event_open() is making use of this? > > I hope I'll send the final series today. From the changelog of the patch > which actually turns the filtering on: > > Testing: > > # perf probe -x /lib/libc.so.6 syscall > > # perl -e 'syscall -1 while 1' & > [1] 530 > > # perf record -e probe_libc:syscall perl -e 'syscall -1 for 1..10; sleep 1' > > # perf report --show-total-period > 100.00% 10 perl libc-2.8.so [.] syscall > > Before this patch: > > # cat /sys/kernel/debug/tracing/uprobe_profile > /lib/libc.so.6 syscall 79291 > > A huge ->nrhit == 79291 reflects the fact that the background process > 530 constantly hits this breakpoint too, even if doesn't contribute to > the output. > > After the patch: > > # cat /sys/kernel/debug/tracing/uprobe_profile > /lib/libc.so.6 syscall 10 > > This shows that only the target process was punished by int3. > > Oleg. > > -- > 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/