From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on dcvr.yhbt.net X-Spam-Level: X-Spam-ASN: AS3215 2.6.0.0/16 X-Spam-Status: No, score=0.6 required=3.0 tests=AWL,BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,RCVD_IN_SORBS_WEB, SPF_HELO_NONE,SPF_PASS,T_SCC_BODY_TEXT_LINE shortcircuit=no autolearn=no autolearn_force=no version=3.4.2 Received: from out1.vger.email (out1.vger.email [IPv6:2620:137:e000::1:20]) by dcvr.yhbt.net (Postfix) with ESMTP id 33A1E1F727 for ; Mon, 27 Jun 2022 16:53:52 +0000 (UTC) Authentication-Results: dcvr.yhbt.net; dkim=pass (2048-bit key; unprotected) header.d=gmail.com header.i=@gmail.com header.b="jO6ZFyy+"; dkim-atps=neutral Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239642AbiF0Qvv (ORCPT ); Mon, 27 Jun 2022 12:51:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47708 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239635AbiF0Qvr (ORCPT ); Mon, 27 Jun 2022 12:51:47 -0400 Received: from mail-pf1-x42c.google.com (mail-pf1-x42c.google.com [IPv6:2607:f8b0:4864:20::42c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6EBA215A08 for ; Mon, 27 Jun 2022 09:51:46 -0700 (PDT) Received: by mail-pf1-x42c.google.com with SMTP id n12so9624160pfq.0 for ; Mon, 27 Jun 2022 09:51:46 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=YD/C58sueHefYrJBK9pmfW7KXgKXShmxFwG33cgKlls=; b=jO6ZFyy+RtKBZW32uhIA+QK4G9wJs3iGmywpnPdZNPSkx7adxTQFo+Y2n1ZrINxjfp nsDxfpmx3UVzoHXpE51c69dTCBNmB39nWz+aOyDlCHm8IiAvi3PaqhtZkqJPmSkZjvmL 0CuTKHSALs1PX408E6Uv34qXnZg55g3SugJII7UrF5DJz0KIHOxv284/nmPsQubFFo5z DBjDRBi/cD2cFUPs2jHOqN5wjZI8AMXwBAgV4RNI2EI9TvqVFOjxPXcSQzJtlilqqlb9 Acp1H1AsXMVzjPOeo0JY+qNgj66PN197KJ9/Cx4CUxt5hc5JpAQdWYj0zqF/4J21nDwc 3NMw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=YD/C58sueHefYrJBK9pmfW7KXgKXShmxFwG33cgKlls=; b=JaDuFnL7utUHSe9L32oHcVh+BTBKlhNupIbI31KiWy6WymrKG+4kXQPocFs9toywFN 2QRUIq51SReW6NQOA70MFuV0iS3TPYUHnOg1P+CQ42TjCg9kV79BjXfLvoGi9mTp3QoK mlad8hD8O3TLlPvf/kuhWUV8nogaPGIKAvkY9cWmeQ7To7y56JMvk6D20TCDtB6aVnLD Hf5011g2EBxejDp8vo4566URe4mNZIZBqYjXtiSM6NdtXXd0TD6gvgBvVKbPTpezs9iW rplAHAtty9gUiKR29oYNPHCwyXGVz/rVTBAonjKTi8jKu9SrNMWFnp+QJcoHY1EVnKWV GP5A== X-Gm-Message-State: AJIora8Vl7o0uxQw6C2tHCMjX8A8BbxfhQkknpY9TxRsGZEec+Ey7hlk E3Mmnj68UnLQbLJGd3218H4itECGK2Y= X-Google-Smtp-Source: AGRyM1v3A1191aSaIUactoEmUOUygG0ucHaq9KWK5g4F7RGyElNyI6zXoSvPARTpjiq7+qp/qATK3Q== X-Received: by 2002:a63:6bc4:0:b0:40d:fd98:bb21 with SMTP id g187-20020a636bc4000000b0040dfd98bb21mr5057153pgc.249.1656348705769; Mon, 27 Jun 2022 09:51:45 -0700 (PDT) Received: from localhost.localdomain ([202.142.80.81]) by smtp.gmail.com with ESMTPSA id v3-20020a170902d68300b0015e8d4eb246sm7456201ply.144.2022.06.27.09.51.43 (version=TLS1_3 cipher=TLS_CHACHA20_POLY1305_SHA256 bits=256/256); Mon, 27 Jun 2022 09:51:45 -0700 (PDT) From: Abhradeep Chakraborty To: Derrick Stolee Cc: Abhradeep Chakraborty , Git , Kaartic Sivaraam , Taylor Blau Subject: Re: [PATCH v2 1/6] Documentation/technical: describe bitmap lookup table extension Date: Mon, 27 Jun 2022 22:21:00 +0530 Message-Id: <20220627165100.16178-1-chakrabortyabhradeep79@gmail.com> X-Mailer: git-send-email 2.35.1 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org Derrick Stolee wrote: > I found this difficult to parse. Here is an attempt at a rewording. Please > let me know if I misunderstood something when reading your version: > > NOTE: The xor_offset stored in the BITMAP_OPT_LOOKUP_TABLE is different > from the xor_offset used in the bitmap data table. The xor_offset in this > table indicates the row number within this table of the commit whose > bitmap is used for the XOR computation with the current commit's stored > bitmap to create the proper logical reachability bitmap. > > This does make me think that "xor_offset" should really be "xor_row" or > something like that. Thanks. `xor_row` seems nice to me. > > + * {empty} > > + commit pos (4 byte integer, network byte order): :: > > + It stores the object position of the commit (in the midx or pack index) > > + to which the i'th bitmap in the bitmap entries belongs. > > Ok, we are saving some space here, but relying on looking into the pack-index > or multi-pack-index to get the actual commit OID. Seems like I didn't update this particular part. At the time of writing this patch, I was clear that I would store these triplets in the bitmap's order. But when I started to implement the "read" part, I realised that these triplets need to be ordered in ascending order. So I did update the "write extension" patch but somehow missed this particular part. Just to be clear, bitmaps are sorted by their commit's date (as far as I know). Bitmaps for recent commits comes before bitmaps for older commits. So these two orders are not same. Thus hashmap would not work here. Will update this portion. Thanks :)