From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932740AbaEPPWM (ORCPT ); Fri, 16 May 2014 11:22:12 -0400 Received: from mx1.redhat.com ([209.132.183.28]:44091 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932664AbaEPPWG (ORCPT ); Fri, 16 May 2014 11:22:06 -0400 Date: Fri, 16 May 2014 10:30:02 -0400 From: Don Zickus To: Jiri Olsa Cc: acme@ghostprotocols.net, peterz@infradead.org, LKML , namhyung@gmail.com, eranian@google.com, Andi Kleen Subject: Re: [PATCH 6/6] perf: Add dcacheline sort Message-ID: <20140516143002.GU50500@redhat.com> References: <1399999697-65875-1-git-send-email-dzickus@redhat.com> <1399999697-65875-7-git-send-email-dzickus@redhat.com> <20140516114757.GD19475@krava.brq.redhat.com> <20140516133058.GN50500@redhat.com> <20140516140551.GF19475@krava.brq.redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140516140551.GF19475@krava.brq.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 On Fri, May 16, 2014 at 04:05:51PM +0200, Jiri Olsa wrote: > On Fri, May 16, 2014 at 09:30:58AM -0400, Don Zickus wrote: > > On Fri, May 16, 2014 at 01:47:57PM +0200, Jiri Olsa wrote: > > > On Tue, May 13, 2014 at 12:48:17PM -0400, Don Zickus wrote: > > > > In perf's 'mem-mode', one can get access to a whole bunch of details specific to a > > > > particular sample instruction. A bunch of those details relate to the data > > > > address. > > > > > > > > One interesting thing you can do with data addresses is to convert them into a unique > > > > cacheline they belong too. Organizing these data cachelines into similar groups and sorting > > > > them can reveal cache contention. > > > > > > > > This patch creates an alogorithm based on various sample details that can help group > > > > entries together into data cachelines and allows 'perf report' to sort on it. > > > > > > > > The algorithm relies on having proper mmap2 support in the kernel to help determine > > > > if the memory map the data address belongs to is private to a pid or globally shared. > > > > > > > > The alogortithm is as follows: > > > > > > > > o group cpumodes together > > > > o group entries with discovered maps together > > > > o sort on major, minor, inode and inode generation numbers > > > > o if userspace anon, then sort on pid > > > > o sort on cachelines based on data addresses > > > > > > needs some collumn width refresh or something..? ;-) > > > > Not sure what you mean here. > > > > > > > > # Overhead Data Cacheline > > > # ........ ....................... > > header not being wide enough to cover the longest data Ah. Ok. So I am not sure the right way to fix that. As the current header seems to be hardcoded with a bunch of spaces. Is there a trick to dynamically space it correctly based on the data provided? > > > > > # > > > 5.42% [k] 0xffff8801ed832c40 > > > 5.29% [.] sys_errlist@@GLIBC_2.12+0xffffffcbf7dfc1ff > > > 3.16% [k] 0xffffffffff5690c0 > > > > > > > > > also I've got again perf hanged up on opening device file > > > > > > [jolsa@krava perf]$ sudo strace -p 29445 > > > Process 29445 attached > > > open("/dev/snd/pcmC0D0p", O_RDONLY^CProcess 29445 detached > > > > > > another one I recall was /dev/dri/card0 touched by X server > > > > > > I guess those device files allow to mmap memory and we recorded > > > memory access there.. we need check for this and do not try to > > > open device files > > > > Ok. And that problem doesn't happen when my patch is not applied? I am > > not sure how this patch causes open device hangs. I'll try to run this on > > a box with X server running to duplicate. > > I think it came with the memory profiling, because we treat > data areas as dsos.. open and look for symbols Yeah, I figured that too. I guess I was trying to point out this is a generic memory profiling issue that isn't related to my patch. But I will still try to track down the problem as it needs to be fixed. :-) Cheers, Don