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,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI,T_DKIMWL_WL_MED 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 7CCD51F404 for ; Tue, 10 Apr 2018 19:10:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752191AbeDJTK4 (ORCPT ); Tue, 10 Apr 2018 15:10:56 -0400 Received: from mail-yb0-f175.google.com ([209.85.213.175]:35019 "EHLO mail-yb0-f175.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751963AbeDJTKz (ORCPT ); Tue, 10 Apr 2018 15:10:55 -0400 Received: by mail-yb0-f175.google.com with SMTP id c1-v6so4700775ybm.2 for ; Tue, 10 Apr 2018 12:10:55 -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=BKGseMxbQ2K5jbCi/rFMk95fqCry+0ToKysKlmM8q+M=; b=b5RsNyZ9lZBtXrXofJjPYqKS5cgz6NSqihAtmbO4fzwikfCBpLx3RuGemYiZ3PoSwx R8DevHbDa3NKXfgGAFqpUkzqHzsYsN4sCVJuyNyTwm6gXrmKtKuMgqCnFJxq2FmGXDFf /lSv7CLzuaXoV3ji62fnXIICPOlRszzWj4W9PCAO9KWjkDr0ntvr+pp+bubn/hYng83a V+tjCy9aAVxYSjOSLtFeBgWHPcTPS9dAHIzQ3b7F4818RU2ob1HJMi+hR/ZNs5rVPT+A 2rwk6ALW/2myPHafGIuZ7lred2UqLbqnxmDFRZ7tK9n00/F+J4Dgv8I6KJPl3DlwcgZp bW2w== 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=BKGseMxbQ2K5jbCi/rFMk95fqCry+0ToKysKlmM8q+M=; b=osU8Wcuv1Iup5ntU0VEJqkzl7aRQ4cdK3cczHtFQwyw3uDnv0ONLIF+K50byZZDFYe tPFjr1I1eS6+7MZ0gGP4X7Rx8/p+bq5UktItuN73Sy9X1EZEiWcyaTP7jdExrcdmpZkn 5IhuAUURDxTC9UP27Dc8IFT2tdjU03LZcM5vm62W50aGn6qLc9qbhsOgAN78p8uiwpaa AMAi0X+2C3vbQh8d8YK+yZ9BXmi9rcJpYWM58L3/7kZ4Qhqr4zSPxRSfFi481BYcrkLJ KKbAUQVlaJzszwKhyzcMN9DQ406JDNIcNdQjfJeeKTykDHDgRqgcSbIF6NtjPWjeliL/ jD7Q== X-Gm-Message-State: ALQs6tDJy09EfVqQQA6Mgs9iTC3mwl+smwVl8ufJDNkg31tqudcrwvK3 i972iOcYPImUa/5t23BGOov3SH8WWw3naf4j+6kdSbxoNXE= X-Google-Smtp-Source: AIpwx4+VsMpYT9Z/bECnXAkwaVY6w72Bk0LfFVT205gslQQGve89HGlNx4GNVahZnWGMV68d1PMycZF9qPTs/ETCiBc= X-Received: by 2002:a25:ba51:: with SMTP id z17-v6mr1039424ybj.334.1523387454636; Tue, 10 Apr 2018 12:10:54 -0700 (PDT) MIME-Version: 1.0 Received: by 2002:a25:cf81:0:0:0:0:0 with HTTP; Tue, 10 Apr 2018 12:10:54 -0700 (PDT) In-Reply-To: <20180410125608.39443-4-dstolee@microsoft.com> References: <20180402203427.170177-1-dstolee@microsoft.com> <20180410125608.39443-1-dstolee@microsoft.com> <20180410125608.39443-4-dstolee@microsoft.com> From: Stefan Beller Date: Tue, 10 Apr 2018 12:10:54 -0700 Message-ID: Subject: Re: [PATCH v8 03/14] commit-graph: add format document To: Derrick Stolee Cc: git , Junio C Hamano , Ramsay Jones , =?UTF-8?Q?SZEDER_G=C3=A1bor?= , Jeff Hostetler , Jeff King , Derrick Stolee Content-Type: text/plain; charset="UTF-8" Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org Hi Derrick, On Tue, Apr 10, 2018 at 5:55 AM, Derrick Stolee wrote: > + OID Fanout (ID: {'O', 'I', 'D', 'F'}) (256 * 4 bytes) > + The ith entry, F[i], stores the number of OIDs with first > + byte at most i. Thus F[255] stores the total > + number of commits (N). I was about to give this series one last read not expecting any questions to come up (this series has had a lot of feedback already!) Although I just did. What were your design considerations for the fanout table? Did you include it as the pack index has one or did you come up with them from first principles? Have you measured the performance impact of the fanout table (maybe even depending on the size of the fanout) ? context: https://public-inbox.org/git/CAJo=hJsto1ik=GTC8c3+2_jBuUqcAPL0UWp-1uoYYMpgbLB+qg@mail.gmail.com/ (side note: searching the web for fanout makes it seem as if it is git-lingo, apparently the term is not widely used) I don't think we want to restart the design discussion, I am just curious. Thanks, Stefan