From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 7843 invoked by alias); 13 Apr 2011 09:07:30 -0000 Received: (qmail 7833 invoked by uid 22791); 13 Apr 2011 09:07:30 -0000 X-SWARE-Spam-Status: No, hits=-2.3 required=5.0 tests=AWL,BAYES_00,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FROM,RCVD_IN_DNSWL_LOW X-Spam-Check-By: sourceware.org Received: from mail-wy0-f175.google.com (HELO mail-wy0-f175.google.com) (74.125.82.175) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Wed, 13 Apr 2011 09:07:16 +0000 Received: by wye20 with SMTP id 20so371535wye.20 for ; Wed, 13 Apr 2011 02:07:15 -0700 (PDT) MIME-Version: 1.0 Received: by 10.227.165.194 with SMTP id j2mr2076016wby.178.1302685635217; Wed, 13 Apr 2011 02:07:15 -0700 (PDT) Received: by 10.227.0.140 with HTTP; Wed, 13 Apr 2011 02:07:15 -0700 (PDT) In-Reply-To: <20110412150901.GI23480@codesourcery.com> References: <20110412141626.GF23480@codesourcery.com> <20110412143205.GG23480@codesourcery.com> <20110412145143.GH23480@codesourcery.com> <20110412150901.GI23480@codesourcery.com> Date: Wed, 13 Apr 2011 09:07:00 -0000 Message-ID: Subject: Re: [PATCH] add statistics counting to postreload, copy-rename, and math-opts From: Richard Guenther To: Nathan Froyd Cc: gcc-patches@gcc.gnu.org Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable X-IsSubscribed: yes Mailing-List: contact gcc-patches-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Id: List-Archive: List-Post: List-Help: Sender: gcc-patches-owner@gcc.gnu.org X-SW-Source: 2011-04/txt/msg00966.txt.bz2 On Tue, Apr 12, 2011 at 5:09 PM, Nathan Froyd wr= ote: > On Tue, Apr 12, 2011 at 04:54:43PM +0200, Richard Guenther wrote: >> On Tue, Apr 12, 2011 at 4:51 PM, Nathan Froyd = wrote: >> > True, but maybe those testcases should be adjusted--per-pass flags, >> > rather than blindly assuming -O2 includes them. =A0And it's not clear = to >> >> It's easier to add things to GCC than to argue removing things ... > > And sometimes not even easy to argue for adding things. :) > >> > me that the statistics_counter_event infrastructure really helps >> > catching do-nothing passes, since it doesn't record stats that increme= nt >> > by zero... >> >> Well, if the overall count is zero then nothing was done. > > Granted, but that fact should still be recorded. =A0The situation we have > today, for something like: > > func1: statistic for "statx" was 0 > =A0- nothing is recorded in the statistics table > func2: statistic for "statx" was 0 > =A0- nothing is recorded in the statistics table > func3: statistic for "statx" was 0 > =A0- nothing is recorded in the statistics table > ... > > and so forth, is that at the end of the day, the dump file won't even > include any information about "statx". =A0If you had some func7387 where > "statx" was non-zero, you could infer that nothing else happened in the > previous 7386 functions. =A0For the case where a pass is truly useless on > a TU, it's hard to figure out from the statistics dump alone. =A0And I'd > argue that it's useful to see explicitly that the pass only helped in 1 > out of 7387 functions, rather than trying to infer it from missing data. I always use statistics-stats (thus, overall stats, not per function). The per function ones omit zero counts during dumping on purpose (to make the dump smaller). Richard. > -Nathan >