From patchwork Tue Oct 10 20:33:30 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Taylor Blau X-Patchwork-Id: 13416038 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 CE89ECD8CB4 for ; Tue, 10 Oct 2023 20:33:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234284AbjJJUdm (ORCPT ); Tue, 10 Oct 2023 16:33:42 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60690 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234393AbjJJUde (ORCPT ); Tue, 10 Oct 2023 16:33:34 -0400 Received: from mail-qv1-xf36.google.com (mail-qv1-xf36.google.com [IPv6:2607:f8b0:4864:20::f36]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6E0F594 for ; Tue, 10 Oct 2023 13:33:32 -0700 (PDT) Received: by mail-qv1-xf36.google.com with SMTP id 6a1803df08f44-65b07651b97so37442076d6.1 for ; Tue, 10 Oct 2023 13:33:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ttaylorr-com.20230601.gappssmtp.com; s=20230601; t=1696970011; x=1697574811; darn=vger.kernel.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=M8raC1pwRNPDQkT90yACQAJIG2zJj06sfDjsWA9vqOU=; b=sJT0KNgHZyV1JglWBV/ah8JdjZLFtkui2F5mzG6Vmaa9twFrgZYeyGODly27YHz/15 CG1ofPIyHvaz4DhIp4+wjsIUEyY6+mOrRJKSImtUO4R5NSOkPBSpaDT3AzxxUa6/rmjj kSzwHWu9/zFdjdjvr7lqcIK5+KI5zDlHPF6itxIPv6jEnustaRtdFLMOfKC8MQ7q0c10 MaqrEKvTYvSO0ZD8zCPHwf94rwvN3Zah2KQFjvz3fUCYHjz1q5XH5qUTGHNYtQ+Q4wgE 4QSjZYIXLdKUlOwTptjtO5vKX8wpGVIOPD/JZQ9kIyVTi+RqHcwRp7up8DNEjGf5IQ5d A7Hw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1696970011; x=1697574811; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=M8raC1pwRNPDQkT90yACQAJIG2zJj06sfDjsWA9vqOU=; b=GQRBhOsBVFfPQVhLf6M2sUrCDZ9SYsfor5MIDcLjYFog7toi/xSeHR+NUHF+GoHqRi 7dHzCLZys3YEPDQLACSboXnrZdC8HZzM4EcQxvu9ThCnBNo/Ow5n3puDpPkGjSuwShxK aUTTg1Ijyxug6QwjJmzjNHy1Y8B5im3G9Myg8RyyIvgCyLuZzlyqpy3W3xG8ItJ2VntE gjTG1ueF+XWri9OKu6dkZfUkgJAlQMhgGZM7rLK9G59jdqARepKvrBNf6dIXOa0bZ4qV YWho8Rhm4gWJOUw5TxizqTi8YrXa+YMxg4+RowmTgzO9fExeZs+c7uLnxBzqcKTaLJk7 6A5A== X-Gm-Message-State: AOJu0YxqscSuqEsg0JdhuWuxifdry+pWL9vcz/qiX3o8pMWcyp52Lt8c BpmfkJKAGJ/UIBOBWjKbFZhoFa9EE9YSURQH5rmMNQ== X-Google-Smtp-Source: AGHT+IH7Cifs0+Hq0a6X63OCrwl/LJQORO4UNZdn2RYGFul2FO3j+nPKqM43xJDPdbgLPTG7k0jh5g== X-Received: by 2002:a05:6214:104d:b0:658:3a12:9949 with SMTP id l13-20020a056214104d00b006583a129949mr20366515qvr.53.1696970011429; Tue, 10 Oct 2023 13:33:31 -0700 (PDT) Received: from localhost (104-178-186-189.lightspeed.milwwi.sbcglobal.net. [104.178.186.189]) by smtp.gmail.com with ESMTPSA id ct5-20020a056214178500b0066cf09f5ba9sm942231qvb.131.2023.10.10.13.33.31 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 10 Oct 2023 13:33:31 -0700 (PDT) Date: Tue, 10 Oct 2023 16:33:30 -0400 From: Taylor Blau To: git@vger.kernel.org Cc: Jonathan Tan , Junio C Hamano , Jeff King , SZEDER =?utf-8?b?R8OhYm9y?= Subject: [PATCH v3 04/17] gitformat-commit-graph: describe version 2 of BDAT Message-ID: <17703ed89ae9a60a26161682ce1c5a468d4ab3e0.1696969994.git.me@ttaylorr.com> References: MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org From: Jonathan Tan 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 --- 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