Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932308Ab2JUQiz (ORCPT ); Sun, 21 Oct 2012 12:38:55 -0400 Received: from mail-wi0-f178.google.com ([209.85.212.178]:36471 "EHLO mail-wi0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754030Ab2JUQiy (ORCPT ); Sun, 21 Oct 2012 12:38:54 -0400 Date: Sun, 21 Oct 2012 18:38:49 +0200 From: Ingo Molnar To: Jiri Olsa Cc: linux-kernel@vger.kernel.org, Arnaldo Carvalho de Melo , Peter Zijlstra , Ingo Molnar , Paul Mackerras , Corey Ashford , Frederic Weisbecker , Namhyung Kim Subject: Re: [PATCH 00/11] perf tool: Add PERF_SAMPLE_READ sample read support Message-ID: <20121021163848.GB28726@gmail.com> References: <1350743599-4805-1-git-send-email-jolsa@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1350743599-4805-1-git-send-email-jolsa@redhat.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2691 Lines: 69 * Jiri Olsa wrote: > hi, > adding support to read sample values through the PERF_SAMPLE_READ > sample type. It's now possible to specify 'S' modifier for an event > and get its sample value by PERF_SAMPLE_READ. > > For group the 'S' modifier will enable sampling only for the leader > and read all the group member by PERF_SAMPLE_READ smple type with > PERF_FORMAT_GROUP read format. > > This patchset is based on group report patches by Namhyung Kim: > http://lwn.net/Articles/518569/ > > Example: > (making sample on cycles, reading both cycles and cache-misses > by PERF_SAMPLE_READ/PERF_FORMAT_GROUP) > > # ./perf record -e '{cycles,cache-misses}:S' ls > ... > > # ./perf report --group --show-total-period --stdio > # ======== > # captured on: Sat Oct 20 16:53:39 2012 > ... > # group: {cycles,cache-misses} > # ======== > # > # Samples: 86 of event 'anon group { cycles, cache-misses }' > # Event count (approx.): 34863674 > # > # Overhead Period Command Shared Object Symbol > # ................ ........................ ....... ................. ................................ Might make sense to consider this column enumeration: # # cycles # | cache-misses # | | > # v v > # > 16.56% 19.47% 5773450 475 ls [kernel.kallsyms] [k] native_sched_clock > 10.87% 0.74% 3789088 18 ls [kernel.kallsyms] [k] rtl8169_interrupt > 9.82% 15.86% 3423364 387 ls [kernel.kallsyms] [k] mark_lock > 8.43% 17.75% 2938384 433 ls ld-2.14.90.so [.] do_lookup_x > 6.79% 20.86% 2365622 509 ls ls [.] calculate_columns > 6.36% 0.61% 2216808 15 ls [kernel.kallsyms] [k] lock_release > ... /me wants this feature ASAP :-) This should probably be the out of box default for perf record and perf top as well - the cache miss rate is probably one of the least appreciated aspects of overhead analysis. Does it have sane output if the cache-misses event is not supported? The cache-misses column should probably stay empty in that case - basically falling back to today's default output. Thanks, Ingo -- 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/