From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753636AbbBSAbR (ORCPT ); Wed, 18 Feb 2015 19:31:17 -0500 Received: from mail-we0-f178.google.com ([74.125.82.178]:33889 "EHLO mail-we0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752323AbbBSAbP (ORCPT ); Wed, 18 Feb 2015 19:31:15 -0500 Date: Thu, 19 Feb 2015 01:31:11 +0100 From: Ingo Molnar To: Bruce Merry Cc: linux-kernel@vger.kernel.org, Peter Zijlstra , Paul Mackerras , Ingo Molnar , Arnaldo Carvalho de Melo , Jiri Olsa , Arnaldo Carvalho de Melo Subject: Re: [PATCH v2] perf bench: fix order of arguments to memcpy_alloc_mem Message-ID: <20150219003111.GA13304@gmail.com> References: <20150115092022.GA11292@kryton> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150115092022.GA11292@kryton> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Bruce Merry wrote: > This was causing the destination instead of the source to be filled. > As a result, the source was typically all mapped to one zero page, > and hence very cacheable. > > Signed-off-by: Bruce Merry > --- > tools/perf/bench/mem-memcpy.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/tools/perf/bench/mem-memcpy.c b/tools/perf/bench/mem-memcpy.c > index 6c14afe..db1d3a2 100644 > --- a/tools/perf/bench/mem-memcpy.c > +++ b/tools/perf/bench/mem-memcpy.c > @@ -289,7 +289,7 @@ static u64 do_memcpy_cycle(const struct routine *r, size_t len, bool prefault) > memcpy_t fn = r->fn.memcpy; > int i; > > - memcpy_alloc_mem(&src, &dst, len); > + memcpy_alloc_mem(&dst, &src, len); > > if (prefault) > fn(dst, src, len); > @@ -312,7 +312,7 @@ static double do_memcpy_gettimeofday(const struct routine *r, size_t len, > void *src = NULL, *dst = NULL; > int i; > > - memcpy_alloc_mem(&src, &dst, len); > + memcpy_alloc_mem(&dst, &src, len); > > if (prefault) > fn(dst, src, len); Acked-by: Ingo Molnar Thanks, Ingo