Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932319Ab3GVQAx (ORCPT ); Mon, 22 Jul 2013 12:00:53 -0400 Received: from merlin.infradead.org ([205.233.59.134]:47128 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756764Ab3GVQAw (ORCPT ); Mon, 22 Jul 2013 12:00:52 -0400 Date: Mon, 22 Jul 2013 13:00:45 -0300 From: Arnaldo Carvalho de Melo To: Hitoshi Mitake Cc: Andi Kleen , linux-kernel@vger.kernel.org, Andi Kleen , h.mitake@gmail.com, kirill.shutemov@linux.intel.com Subject: Re: [PATCH] perf, tools, bench: Fix memcpy benchmark for large sizes v2 Message-ID: <20130722160045.GG2157@ghostprotocols.net> References: <1374187398-14234-1-git-send-email-andi@firstfloor.org> <87ip064k60.wl%mitake.hitoshi@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87ip064k60.wl%mitake.hitoshi@gmail.com> X-Url: http://acmel.wordpress.com User-Agent: Mutt/1.5.21 (2010-09-15) X-SRS-Rewrite: SMTP reverse-path rewritten from by merlin.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1299 Lines: 32 Em Sat, Jul 20, 2013 at 12:57:27AM +0900, Hitoshi Mitake escreveu: > At Thu, 18 Jul 2013 15:43:18 -0700, Andi Kleen wrote: > > glibc calloc() has an optimization to not explicitely memset() > > very large calloc allocations that just came from mmap(), > > because they are known to be zero. > > This could result in the perf memcpy benchmark reading only from > > the zero page, which gives unrealistic results. > > Always call memset explicitly on the source area to avoid this problem. > > +++ b/tools/perf/bench/mem-memcpy.c > > @@ -115,8 +115,10 @@ static void alloc_mem(void **dst, void **src, size_t length) > > *src = zalloc(length); > > - if (!src) > > + if (!*src) > In the latest mem-memcpy.c, this if (!src) is already fixed as if > (!*src). This modification makes applying fail. I fixed this up, please take a look at: https://git.kernel.org/cgit/linux/kernel/git/acme/linux.git/commit/?h=perf/core&id=a198996c7afae0097c67a61851f19863e59697b2 https://git.kernel.org/cgit/linux/kernel/git/acme/linux.git/log/?h=perf/core - Arnaldo -- 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/