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=-3.7 required=3.0 tests=AWL,BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,RCVD_IN_DNSWL_HI, 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 AF4CD202A5 for ; Mon, 25 Sep 2017 23:42:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S966579AbdIYXmG (ORCPT ); Mon, 25 Sep 2017 19:42:06 -0400 Received: from mail-qk0-f175.google.com ([209.85.220.175]:49835 "EHLO mail-qk0-f175.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S966545AbdIYXmE (ORCPT ); Mon, 25 Sep 2017 19:42:04 -0400 Received: by mail-qk0-f175.google.com with SMTP id u67so8429626qkg.6 for ; Mon, 25 Sep 2017 16:42:04 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc; bh=eHDZanS57F2QmPKk8UalRQ3Ac318lYf9UYODNJ77UiQ=; b=iXpUA0q2ZWVWJPWc2SIS0z0odlCDVmGheOIbMu/qLcYkuEOhyyPmR8PipU2Vwme0KY oEPk4gFugHhhWEwjh35IeQKjb8NeM0SgJI9dKKHenyXAzgOlgN7MQlBNmGUsads2L8V0 eJw1hoB7xtr5Ur4eeLscbIf7LnVY6TDlwk0iVwJjzZID+q4ZxFbTXdaEUbKLStqa9lF+ jh01xYCZACaeV7lkJWRN2niLV9C/MfbFRlEVfwduMsyETMLyfi8oU/umTCFIpfutInWf M0wo1jM+gEu+luixLEnIOiJ6SuDdc0CtWZx5dlF0iGPhjlRNV8sbKSpGzOVDyN+cQSUW Y1yg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to:cc; bh=eHDZanS57F2QmPKk8UalRQ3Ac318lYf9UYODNJ77UiQ=; b=FYyPUE5uqZccaRxelPgAnOVdYnuljmutc7hpVXSDjMVmfyPrAsM7XZDB12xG48uhF+ QBC/YCjeTsUXbw3riEHojwz/DO4mUz8wfIf29j2nCu6aBphDc/lilJgpGUkThuglJ80/ 0SFDn3FlaaFsuhbDh3xQgqg58hK+FlHLODKd7pMKiP0Rjyl0hYsetz4UAuYB3npVTki+ FB2D1U0KVKk6UpCuY/N1ovz774bYuLOG2Vq83mzj80L1VdP9AXo39Oth0iIEeBCTuYNu Cbaej1wftjAnMvli5iYcNABN2UmPnbTzlubjMsUIfIuS2oQj0GriMDfEmrpGt0cRw7z4 PIEw== X-Gm-Message-State: AHPjjUh/ezTbI+4vNJrcDZNH/MdF3Z6pf+a6dSKjOs/jxtDKihKLGwJE GfzlIsfAFcHjFVlrb2ZUehqTCpvM4dnIBX1gQVpcswADC74= X-Google-Smtp-Source: AOwi7QDKsFEOT/NJQLxUPg6x+M2LK9eaKsGWmypJgC4sQk7+ak+JkEziklP8PuvWve/KbKxEkr9Rh4S/1hcbZOxFLbc= X-Received: by 10.55.52.135 with SMTP id b129mr12897059qka.308.1506382923668; Mon, 25 Sep 2017 16:42:03 -0700 (PDT) MIME-Version: 1.0 Received: by 10.140.102.51 with HTTP; Mon, 25 Sep 2017 16:42:03 -0700 (PDT) In-Reply-To: <20170925095452.66833-5-dstolee@microsoft.com> References: <20170925095452.66833-1-dstolee@microsoft.com> <20170925095452.66833-5-dstolee@microsoft.com> From: Stefan Beller Date: Mon, 25 Sep 2017 16:42:03 -0700 Message-ID: Subject: Re: [PATCH v2 4/5] sha1_name: Parse less while finding common prefix To: Derrick Stolee Cc: "git@vger.kernel.org" , stolee@gmail.com, Jeff Hostetler Content-Type: text/plain; charset="UTF-8" Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org On Mon, Sep 25, 2017 at 2:54 AM, Derrick Stolee wrote: > Create get_hex_char_from_oid() to parse oids one hex character at a > time. This prevents unnecessary copying of hex characters in > extend_abbrev_len() when finding the length of a common prefix. > > p0008.1: find_unique_abbrev() for existing objects > -------------------------------------------------- > > For 10 repeated tests, each checking 100,000 known objects, we find the > following results when running in a Linux VM: > > | | Pack | Packed | Loose | Base | New | | > | Repo | Files | Objects | Objects| Time | Time | Rel% | > |-------|-------|---------|--------|--------|--------|--------| > | Git | 1 | 230078 | 0 | 0.08 s | 0.08 s | 0.0% | > | Git | 5 | 230162 | 0 | 0.17 s | 0.16 s | - 5.9% | > | Git | 4 | 154310 | 75852 | 0.14 s | 0.12 s | -14.3% | > | Linux | 1 | 5606645 | 0 | 0.50 s | 0.25 s | -50.0% | > | Linux | 24 | 5606645 | 0 | 2.41 s | 2.08 s | -13.7% | > | Linux | 23 | 5283204 | 323441 | 1.99 s | 1.69 s | -15.1% | > | VSTS | 1 | 4355923 | 0 | 0.40 s | 0.22 s | -45.0% | > | VSTS | 32 | 4355923 | 0 | 2.09 s | 1.99 s | - 4.8% | > | VSTS | 31 | 4276829 | 79094 | 3.60 s | 3.20 s | -11.1% | > > For the Windows repo running in Windows Subsystem for Linux: > > Pack Files: 50 > Packed Objects: 22,385,898 > Loose Objects: 492 > Base Time: 4.61 s > New Time: 4.61 s > Rel %: 0.0% > > p0008.2: find_unique_abbrev() for missing objects > ------------------------------------------------- > > For 10 repeated tests, each checking 100,000 missing objects, we find > the following results when running in a Linux VM: > > | | Pack | Packed | Loose | Base | New | | > | Repo | Files | Objects | Objects| Time | Time | Rel% | > |-------|-------|---------|--------|--------|--------|--------| > | Git | 1 | 230078 | 0 | 0.06 s | 0.05 s | -16.7% | > | Git | 5 | 230162 | 0 | 0.14 s | 0.15 s | + 7.1% | > | Git | 4 | 154310 | 75852 | 0.12 s | 0.12 s | 0.0% | > | Linux | 1 | 5606645 | 0 | 0.40 s | 0.17 s | -57.5% | > | Linux | 24 | 5606645 | 0 | 1.59 s | 1.30 s | -18.2% | > | Linux | 23 | 5283204 | 323441 | 1.23 s | 1.10 s | -10.6% | > | VSTS | 1 | 4355923 | 0 | 0.25 s | 0.12 s | -52.0% | > | VSTS | 32 | 4355923 | 0 | 1.45 s | 1.34 s | - 7.6% | > | VSTS | 31 | 4276829 | 79094 | 1.59 s | 1.34 s | -15.7% | > > For the Windows repo running in Windows Subsystem for Linux: > > Pack Files: 50 > Packed Objects: 22,385,898 > Loose Objects: 492 > Base Time: 3.91 s > New Time: 3.08 s > Rel %: -21.1% > These number look pretty cool! > Signed-off-by: Derrick Stolee > > Signed-off-by: Derrick Stolee double signoff? > --- > sha1_name.c | 13 +++++++++++-- > 1 file changed, 11 insertions(+), 2 deletions(-) > > diff --git a/sha1_name.c b/sha1_name.c > index f2a1ebe49..bb47b6702 100644 > --- a/sha1_name.c > +++ b/sha1_name.c > @@ -480,13 +480,22 @@ struct min_abbrev_data { > char *hex; > }; > > +static inline char get_hex_char_from_oid(const struct object_id *oid, int i) 'i' is not very descriptive, maybe add a comment? (I realize it is just walking through the char*s one by one) Maybe this function (together with the change in the while below) could go into hex.c as "int progressively_cmp_oids" that returns the position at which the given oids differ? > +{ > + static const char hex[] = "0123456789abcdef"; > + > + if ((i & 1) == 0) > + return hex[oid->hash[i >> 1] >> 4]; > + else > + return hex[oid->hash[i >> 1] & 0xf]; > +} sha1_to_hex_r has very similar code, though it iterates less and covers both cases in the loop body. That is the actual reason I propose moving this function (or a variant thereof) to hex.c as there we can share code.