From patchwork Wed Aug 30 16:43:41 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jonathan Tan X-Patchwork-Id: 13370376 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 43DF7C83F01 for ; Wed, 30 Aug 2023 18:29:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230237AbjH3S3S (ORCPT ); Wed, 30 Aug 2023 14:29:18 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39908 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1343742AbjH3QoK (ORCPT ); Wed, 30 Aug 2023 12:44:10 -0400 Received: from mail-yw1-x114a.google.com (mail-yw1-x114a.google.com [IPv6:2607:f8b0:4864:20::114a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7C5851A3 for ; Wed, 30 Aug 2023 09:44:07 -0700 (PDT) Received: by mail-yw1-x114a.google.com with SMTP id 00721157ae682-594e8207103so61968297b3.2 for ; Wed, 30 Aug 2023 09:44:07 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20221208; t=1693413841; x=1694018641; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=QoHkY0gwz3nTB1tdRU4Jvo65AWGB7v8s4sgW6WMdEOs=; b=1RbBJOt/QldDkliZgq+ZJNzgX1zJN2S80aQai7lUKu3E0GI3aGPN2Biyxwe9UtuCXd fWkM28BXJE7Yz25aBlHNeX/PIqcAt5vFsKuE5BTFItKagQIMrEpepZsCUsj1ldzG7xb/ AoIhnOEh3yfsZEs0mrPAqQmMG1XpYQFGpDGaiZkQTlB5YwsBBEW/DhAQLTFx8N1MOW/f bkpifJ4QVpbv/j/BjvOa7xb5EXF0dOhC4i19cuVtaYhdb2ZSE//pikS62NkuVNF8hw0/ mC+5QvMJPynR+HEKhzWfGi4vjWpeigwCQ6Wj8SKWzVloXpalq2SxOxWyyYhcN0fdjHm2 iJJw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1693413841; x=1694018641; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=QoHkY0gwz3nTB1tdRU4Jvo65AWGB7v8s4sgW6WMdEOs=; b=NH4aqT7l9MRtA7oPr5yj0HjDmfsQfssPKslhgdAEbs2VGAMgn9vBGohlymXEw+Dndz WSXH6ECTZcGp/geuzHvrNvEro59G7m4pVBNiXMZ1H32NxsuKvUL1lVVLzf0iv7HG3ozp CVJaGXQm7i08vi5+dWqh5FUFtyHTvv4IuG8PC40pBcgoic2s2zG0doqbSaIgQn6lVv// kwvmuN4UL8mkPs8dffscJd3dYDIcdZnUL1OnCHRtnNkUNKWltwRlHcAPncFjS7MACBNQ Vt6gaFTjymx+MfuOvEJ1Mgzexu3cN9P0PpxNdaf4XvrZcxEOAW3ntPyKkqWblwulqTre XwVA== X-Gm-Message-State: AOJu0Ywf+X8gE7rqyGQ0+xSCOGG3DEH1UHgbF50vPtrWYpx4+rMiq3Mo IHyNfs8GQhSn5j1zKsEepIsspzmoalKzwa52T4DFzOiPDc+651S0IjN6iGyrT0Ur8+8uEeitxp0 hix2vitDB+RNLxvkmsqXXz3TdCCliZWaugoRn63bfOHmcjj9wmtfw1fxJZmdUHg11QAx/7pWcbY Fa X-Google-Smtp-Source: AGHT+IEuhrYMLPQ9ipbsdb8whi98ootygiZcsYyHFLWWi2SJokMXRwzW0FjciqOHwXQD747Sjo8l1s1Qqi1lnrOGwuzZ X-Received: from jonathantanmy0.svl.corp.google.com ([2620:15c:2d3:204:2899:32d6:b7e3:8e6e]) (user=jonathantanmy job=sendgmr) by 2002:a25:ced0:0:b0:d77:d70c:b5cd with SMTP id x199-20020a25ced0000000b00d77d70cb5cdmr71148ybe.12.1693413841694; Wed, 30 Aug 2023 09:44:01 -0700 (PDT) Date: Wed, 30 Aug 2023 09:43:41 -0700 In-Reply-To: Mime-Version: 1.0 References: X-Mailer: git-send-email 2.42.0.rc2.253.gd59a3bf2b4-goog Message-ID: Subject: [PATCH v2 01/15] gitformat-commit-graph: describe version 2 of BDAT From: Jonathan Tan To: git@vger.kernel.org Cc: Jonathan Tan , Junio C Hamano , "SZEDER =?utf-8?b?R8OhYm9y?= " , Taylor Blau Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org The code change to Git to support version 2 will be done in subsequent commits. Signed-off-by: Jonathan Tan Signed-off-by: Junio C Hamano Signed-off-by: Taylor Blau Signed-off-by: Junio C Hamano --- Documentation/gitformat-commit-graph.txt | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/Documentation/gitformat-commit-graph.txt b/Documentation/gitformat-commit-graph.txt index 31cad585e2..3e906e8030 100644 --- a/Documentation/gitformat-commit-graph.txt +++ b/Documentation/gitformat-commit-graph.txt @@ -142,13 +142,16 @@ All multi-byte numbers are in network byte order. ==== Bloom Filter Data (ID: {'B', 'D', 'A', 'T'}) [Optional] * It starts with header consisting of three unsigned 32-bit integers: - - Version of the hash algorithm being used. We currently only support - value 1 which corresponds to the 32-bit version of the murmur3 hash + - Version of the hash algorithm being used. We currently support + value 2 which corresponds to the 32-bit version of the murmur3 hash implemented exactly as described in https://en.wikipedia.org/wiki/MurmurHash#Algorithm and the double hashing technique using seed values 0x293ae76f and 0x7e646e2 as described in https://doi.org/10.1007/978-3-540-30494-4_26 "Bloom Filters - in Probabilistic Verification" + in Probabilistic Verification". Version 1 Bloom filters have a bug that appears + when char is signed and the repository has path names that have characters >= + 0x80; Git supports reading and writing them, but this ability will be removed + in a future version of Git. - The number of times a path is hashed and hence the number of bit positions that cumulatively determine whether a file is present in the commit. - The minimum number of bits 'b' per entry in the Bloom filter. If the filter