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=-3.1 required=3.0 tests=AWL,BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,RCVD_IN_DNSWL_HI,RCVD_IN_SORBS_SPAM, RP_MATCHES_RCVD shortcircuit=no autolearn=no 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 1F03C20966 for ; Thu, 30 Mar 2017 20:06:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934879AbdC3UGf (ORCPT ); Thu, 30 Mar 2017 16:06:35 -0400 Received: from mail-wr0-f196.google.com ([209.85.128.196]:36649 "EHLO mail-wr0-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934850AbdC3UGa (ORCPT ); Thu, 30 Mar 2017 16:06:30 -0400 Received: by mail-wr0-f196.google.com with SMTP id k6so13803260wre.3 for ; Thu, 30 Mar 2017 13:06:23 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=O/G/rLIvTkFXIdWreSJF7DW9+HZumTf54jfjeqUDOeU=; b=H9GZUV1tEWN2lU8G+jZzMmddC0Lhlj5PAXdj6Irwkf39LJ4iugxa/PwF25YS+F42WE wVIgZRn4zetrxzOepLf7qulJG4XqsjE825YYBxA5rlBSSoAq+JOvy0tqnCARz6N+m9JL hhRKsKZHmplHhYtGucbBwtYxAsZEhpk9AcNhFae4Z3AhLvPb22Nv+ML7K+LnZdkdNX0M Pw4XqMqX0zCj+8soqFH4PmFUqZoHG7cokS9vXDH7zW4GZ/eyzXW6h7SYU1gZOfXy9Ita u43kAwci3LdyYh/IKL0q60N4pP1GUb6a6KBxaOXSQ1kCWVf8/Elm+V4VRvUBjNLbpEv6 ZyOg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=O/G/rLIvTkFXIdWreSJF7DW9+HZumTf54jfjeqUDOeU=; b=UFjHwleni+eAIN1yDbZVo2Xex3Hvcup6QUghT7q/M8jLEKJ5py8ubFubqVCGM05doC JbPpKdUray1gGyrUVj94/W7FP0Nk+xvTGT2FE9QBt+Op9DkEEmhlXmTubGFcVEVJuC5g mhCqpkXZjA8ElUlg4htbr6fwG2bFnguOo5Ehtyu6d1Y5ARI36OBAv38S6kgxVg5Qipnd yAE10AXE0XGpka1+ACjaz6cCYUGsTdkIQfPJjhFhGGxWeI5OKFhX+qXMTuQB6tiQB/qU EkqUIJpuBvdeXPiJ+OmUqiQ5+lDSVLVWwKFZrLFJ3umher4HWQND7hflXyTBPKvlazf2 h+Zg== X-Gm-Message-State: AFeK/H2QFTUpr6lUQmRK56YGSTJMn8Kbg0EpklunbEbPksfvTJtRaoE7+mOHNhQG39/5Ig== X-Received: by 10.223.178.182 with SMTP id g51mr1341521wrd.12.1490904382779; Thu, 30 Mar 2017 13:06:22 -0700 (PDT) Received: from localhost ([2a02:c7f:c42b:f900:5e51:4fff:fee9:57af]) by smtp.gmail.com with ESMTPSA id x131sm145728wme.28.2017.03.30.13.06.21 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Thu, 30 Mar 2017 13:06:22 -0700 (PDT) Date: Thu, 30 Mar 2017 21:06:48 +0100 From: Thomas Gummerer To: Jeff King Cc: Jeff Hostetler , git@vger.kernel.org, gitster@pobox.com, Jeff Hostetler Subject: Re: [PATCH v3 0/2] read-cache: call verify_hdr() in a background thread Message-ID: <20170330200648.GH27158@hank> References: <20170328190732.59486-1-git@jeffhostetler.com> <20170328191628.dprziuhpv7khvocu@sigill.intra.peff.net> <35f220df-aa63-b80f-8970-429850202cdd@jeffhostetler.com> <20170328195605.xy4pnhy74s6wgwps@sigill.intra.peff.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170328195605.xy4pnhy74s6wgwps@sigill.intra.peff.net> User-Agent: Mutt/1.5.23.1-rc1 (2014-03-12) Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org On 03/28, Jeff King wrote: > On Tue, Mar 28, 2017 at 03:50:34PM -0400, Jeff Hostetler wrote: > > > It was a convenient way to isolate, average, and compare > > read_index() times, but I suppose we could do something > > like that. > > > > I did confirm that a ls-files does show a slight 0.008 > > second difference on the 58K file Linux tree when toggled > > on or off. > > Yeah, I agree it helps isolate the change. I'm just not sure we want to > carry a bunch of function-specific perf-testing code. And one of the > nice things about testing a real command is that it's...a real command. > So it's an actual improvement a user might see. > > > But I'm tempted to suggest that we just omit my helper exe > > and not worry about a test -- since we don't have any test > > repos large enough to really demonstrate the differences. > > My concern is that that 0.008 would be lost in the noise > > of the rest of the test and make for an unreliable result. > > Yeah, I think that would be fine. You _could_ write a t/perf test and > then use your 400MB monstrosity as GIT_PERF_LARGE_REPO. But given that > most people don't have such a thing, there's not much value over you > just showing off the perf improvement in the commit message. Sorry if this was already discussed, but we already do have a perf test for the index (p0002), and a corresponding helper program which just does read_cache() and discard_cache(). Maybe we could re-use that and add a second test running the same using the new config? > We could also have a t/perf test that generates a monstrous index and > shows that it's faster. But frankly, I don't think this is all that > interesting as a performance regression test. It's not like there's > something subtle about the performance improvement; we stopped computing > the SHA-1, and (gasp!) it takes exactly one SHA-1 computation's less > time. > > So just mentioning the test case and the improvement in the commit > message is sufficient, IMHO. > > -Peff