From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on dcvr.yhbt.net X-Spam-Level: X-Spam-ASN: AS31976 209.132.180.0/23 X-Spam-Status: No, score=-4.0 required=3.0 tests=AWL,BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI shortcircuit=no autolearn=ham autolearn_force=no version=3.4.2 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by dcvr.yhbt.net (Postfix) with ESMTP id EE81820248 for ; Tue, 26 Mar 2019 05:38:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726175AbfCZFil (ORCPT ); Tue, 26 Mar 2019 01:38:41 -0400 Received: from cloud.peff.net ([104.130.231.41]:36070 "HELO cloud.peff.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1725497AbfCZFil (ORCPT ); Tue, 26 Mar 2019 01:38:41 -0400 Received: (qmail 8692 invoked by uid 109); 26 Mar 2019 05:38:41 -0000 Received: from Unknown (HELO peff.net) (10.0.1.2) by cloud.peff.net (qpsmtpd/0.94) with SMTP; Tue, 26 Mar 2019 05:38:41 +0000 Authentication-Results: cloud.peff.net; auth=none Received: (qmail 15006 invoked by uid 111); 26 Mar 2019 05:39:04 -0000 Received: from sigill.intra.peff.net (HELO sigill.intra.peff.net) (10.0.0.7) by peff.net (qpsmtpd/0.94) with (ECDHE-RSA-AES256-GCM-SHA384 encrypted) SMTP; Tue, 26 Mar 2019 01:39:04 -0400 Authentication-Results: peff.net; auth=none Received: by sigill.intra.peff.net (sSMTP sendmail emulation); Tue, 26 Mar 2019 01:38:39 -0400 Date: Tue, 26 Mar 2019 01:38:39 -0400 From: Jeff King To: SZEDER =?utf-8?B?R8OhYm9y?= Cc: git@vger.kernel.org, Junio C Hamano , =?utf-8?B?w4Z2YXIgQXJuZmrDtnLDsA==?= Bjarmason Subject: Re: [PATCH 2/5] progress: return early when in the background Message-ID: <20190326053839.GC1933@sigill.intra.peff.net> References: <20190325103844.26749-1-szeder.dev@gmail.com> <20190325103844.26749-3-szeder.dev@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20190325103844.26749-3-szeder.dev@gmail.com> Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org On Mon, Mar 25, 2019 at 11:38:41AM +0100, SZEDER Gábor wrote: > diff --git a/progress.c b/progress.c > index 02a20e7d58..b57c0dae16 100644 > --- a/progress.c > +++ b/progress.c > @@ -86,28 +86,30 @@ static void display(struct progress *progress, uint64_t n, const char *done) > return; > > progress->last_value = n; > + > + if (!is_foreground_fd(fileno(stderr)) && !done) { > + progress_update = 0; > + return; > + } > + Moving it here causes a measurable slowdown for: git rev-list --progress=foo --objects --all This function gets called for every single increment of the progress counter. Whereas in its old location: > tp = (progress->throughput) ? progress->throughput->display.buf : ""; > eol = done ? done : " \r"; > if (progress->total) { > unsigned percent = n * 100 / progress->total; > if (percent != progress->last_percent || progress_update) { > progress->last_percent = percent; > - if (is_foreground_fd(fileno(stderr)) || done) { > - fprintf(stderr, "%s: %3u%% (%"PRIuMAX"/%"PRIuMAX")%s%s", > - progress->title, percent, > - (uintmax_t)n, (uintmax_t)progress->total, > - tp, eol); > - fflush(stderr); > - } It was only triggered when we accumulated enough increments to print. So we save a few instructions in the backgrounded case, but it costs us a lot of extra syscalls in every other case. According to "strace -c", the number of ioctls for that rev-list on git.git went from 6 to 373,461. But more importantly, my best-of-five timings went from 3.340s from 3.407s. That's only 2%, but it would be nice not to pay it if we don't need to. -Peff