From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B084BC433F5 for ; Thu, 16 Sep 2021 22:49:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9611C611F2 for ; Thu, 16 Sep 2021 22:49:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241275AbhIPWvN (ORCPT ); Thu, 16 Sep 2021 18:51:13 -0400 Received: from cloud.peff.net ([104.130.231.41]:49578 "EHLO cloud.peff.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241276AbhIPWvN (ORCPT ); Thu, 16 Sep 2021 18:51:13 -0400 Received: (qmail 8778 invoked by uid 109); 16 Sep 2021 22:49:51 -0000 Received: from Unknown (HELO peff.net) (10.0.1.2) by cloud.peff.net (qpsmtpd/0.94) with ESMTP; Thu, 16 Sep 2021 22:49:51 +0000 Authentication-Results: cloud.peff.net; auth=none Received: (qmail 10105 invoked by uid 111); 16 Sep 2021 22:49:51 -0000 Received: from coredump.intra.peff.net (HELO sigill.intra.peff.net) (10.0.0.2) by peff.net (qpsmtpd/0.94) with (TLS_AES_256_GCM_SHA384 encrypted) ESMTPS; Thu, 16 Sep 2021 18:49:51 -0400 Authentication-Results: peff.net; auth=none Date: Thu, 16 Sep 2021 18:49:50 -0400 From: Jeff King To: Taylor Blau Cc: git@vger.kernel.org, gitster@pobox.com, avarab@gmail.com Subject: Re: [PATCH v2 7/7] t5326: test propagating hashcache values Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org On Tue, Sep 14, 2021 at 06:06:16PM -0400, Taylor Blau wrote: > Now that we both can propagate values from the hashcache, and respect > the configuration to enable the hashcache at all, test that both of > these function correctly by hardening their behavior with a test. > > Like the hash-cache in classic single-pack bitmaps, this helps more > proportionally the more up-to-date your bitmap coverage is. When our > bitmap coverage is out-of-date with the ref tips, we spend more time > proportionally traversing, and all of that traversal gets the name-hash > filled in. > > But for the up-to-date bitmaps, this helps quite a bit. These numbers > are on git.git, with `pack.threads=1` to help see the difference > reflected in the overall runtime. > > Test origin/tb/multi-pack-bitmaps HEAD > ------------------------------------------------------------------------------------- > 5326.4: simulated clone 1.87(1.80+0.07) 1.46(1.42+0.03) -21.9% > 5326.5: simulated fetch 2.66(2.61+0.04) 1.47(1.43+0.04) -44.7% > 5326.6: pack to file (bitmap) 2.74(2.62+0.12) 1.89(1.82+0.07) -31.0% The percentages here match timings I did. Doing it with linux.git gives bigger absolute numbers, but I think this is sufficient (and a lot less painful when people are trying to replicate). > +test_expect_success 'hash-cache values are propagated from pack bitmaps' ' > + rm -fr repo && > + git init repo && > + test_when_finished "rm -fr repo" && > + ( > + cd repo && > + > + git config pack.writeBitmapHashCache true && This is the default as of your earlier commits, so we could probably drop this. I don't mind keeping it as explicit documentation of what we expect, though. -Peff