From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on dcvr.yhbt.net X-Spam-Level: X-Spam-ASN: AS31976 209.132.180.0/23 X-Spam-Status: No, score=-3.9 required=3.0 tests=AWL,BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI, T_RP_MATCHES_RCVD shortcircuit=no autolearn=ham autolearn_force=no version=3.4.0 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by dcvr.yhbt.net (Postfix) with ESMTP id ADFAE1F42D for ; Fri, 6 Apr 2018 21:40:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751896AbeDFVkK (ORCPT ); Fri, 6 Apr 2018 17:40:10 -0400 Received: from cloud.peff.net ([104.130.231.41]:56566 "HELO cloud.peff.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1751532AbeDFVkJ (ORCPT ); Fri, 6 Apr 2018 17:40:09 -0400 Received: (qmail 29775 invoked by uid 109); 6 Apr 2018 21:40:09 -0000 Received: from Unknown (HELO peff.net) (10.0.1.2) by cloud.peff.net (qpsmtpd/0.94) with SMTP; Fri, 06 Apr 2018 21:40:09 +0000 Authentication-Results: cloud.peff.net; auth=none Received: (qmail 30153 invoked by uid 111); 6 Apr 2018 21:41:10 -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; Fri, 06 Apr 2018 17:41:10 -0400 Authentication-Results: peff.net; auth=none Received: by sigill.intra.peff.net (sSMTP sendmail emulation); Fri, 06 Apr 2018 17:40:07 -0400 Date: Fri, 6 Apr 2018 17:40:07 -0400 From: Jeff King To: Johannes Schindelin Cc: =?utf-8?B?w4Z2YXIgQXJuZmrDtnLDsA==?= Bjarmason , Stefan Beller , git , Junio C Hamano , Thomas Rast , Phil Haack , Jason Frey , Philip Oakley , Duy Nguyen Subject: Re: A potential approach to making tests faster on Windows Message-ID: <20180406214006.GE7870@sigill.intra.peff.net> References: <899ea23951627426ccd0aac79f824af386c5590c.1522336130.git.johannes.schindelin@gmx.de> <20180329194159.GB2939@sigill.intra.peff.net> <87fu4hwgfa.fsf@evledraar.gmail.com> <20180403132717.GC18824@sigill.intra.peff.net> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org On Tue, Apr 03, 2018 at 06:00:05PM +0200, Johannes Schindelin wrote: > > But if we're at the point of creating custom C builtins for > > busybox/dash/etc, you should be able to create a primitive for "read > > this using buffered stdio, other processes be damned, and return one > > line at a time". > > Well, you know, I do not think that papering over the root cause will make > anything better. And the root cause is that we use a test framework > written in Unix shell. I'm not entirely convinced of this. My earlier numbers show that we spend a lot of time actually running Git. But that's not because we're written in shell, but because the stable interface to Git is running individual processes. So we can unit-test wildmatch or similar in a single C program, but I think we inherently need to run "git init" a lot of times. Now I think there's reason to doubt some of my numbers. I was counting exec's, and non-exec forks due to subshells, etc, may be important. So I claim only that I remain unconvinced that we are certain of the root cause. At any rate, I would be happy to see more study into this. If we can create a measurable speedup for an existing script, that might give us a blueprint for speeding up the whole suite. -Peff