From mboxrd@z Thu Jan 1 00:00:00 1970 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 CAD26C0015E for ; Tue, 1 Aug 2023 18:42:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229814AbjHASmK (ORCPT ); Tue, 1 Aug 2023 14:42:10 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53308 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230401AbjHASmH (ORCPT ); Tue, 1 Aug 2023 14:42:07 -0400 Received: from mail-yb1-xb49.google.com (mail-yb1-xb49.google.com [IPv6:2607:f8b0:4864:20::b49]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6C1B12712 for ; Tue, 1 Aug 2023 11:41:50 -0700 (PDT) Received: by mail-yb1-xb49.google.com with SMTP id 3f1490d57ef6-c5fc972760eso6471559276.1 for ; Tue, 01 Aug 2023 11:41:50 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20221208; t=1690915309; x=1691520109; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=UP7ngzbctY+J++YVHHRiOWNnUiMb65kHHS+WU+BGA8c=; b=nU8JKLA1xPNR9sukGBFIYhTtIVJmUQNrrNVV3GBmCxN852Kd5LC9qmtPDHFxNg+Eqh rJncHVYSQ/L4N8Kp1yzEsXR98uZ/piij33g1n8/Cs80rgKvqG4fIN0Jb7uqztmhEOPkz 2lFHTaRFAeQAkaAj5du1S/OJtDbFCI3F4GP1wa64kGzkUtac485sjoOmoBjy+KGVXZHL Zv4c+G8GZuyUYE30lFzTbB1XYuGsAQjmSxKOGKn5M1f6zU/QQ6F+gp7oeRPQDHPIdeoS bpZIATcVgPlxUXpbfHcvF3ml1UO7IzY0MLXXyzpMB/EL5lcjRoxpSrQcuvMllDaujF54 t+2A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1690915309; x=1691520109; 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=UP7ngzbctY+J++YVHHRiOWNnUiMb65kHHS+WU+BGA8c=; b=PVqX6MInDLlYxulMUEji07UjkRtIB6XP/j6q3dZ+ur1aiYjmq+ya1lozqFPOtbiXBZ BekGhw9/z7+zEMBONyyiUY187VX+76ceYpks3OXqmGtzP6xDZP2yw/h/2IbZnE31W6I0 6YGMiemUyrrGWWwWZz++NwJ4Px1gCpPf9crY0nGiearcIVE7bNv4a/U7XBFVwRtGMLFg 2tiIFFxMoWHIX4tEnR27N9s9Y+D7M7oc/rRiBPwKtr9HXfol4jv7ft6XuXNz+s0HBIfD mbxca8hL4DGM3dHg5yXHWg3E7Hz8yyAM99ApSojIniTYURisZz78VJBWZ6wDEscu0TbB Y9QQ== X-Gm-Message-State: ABy/qLaDBWgB5Xfez2s11UsirL97Hb0nxfPfAHRE1mvAjZGXjF4y6oIn bm3hFBykdcUwdGeMA+l7HtlZ/6HyP8ZBKYicw0gwDryE0UD+Zz0tvOqH39n20pryVgBdDOPDmHs uO7aYOROIPW9igx9NiLXutsk0c+ymCrBb5t9j9VUwBth4UtpioRXZ+V/tuZukvzNY2QwGD6lS8g E3 X-Google-Smtp-Source: APBJJlFJTNfgzdLrXLm/guh0YrliKW9HlX8PNeMrosHSf1zQAXg9MYtrQdTUJZnb6QkY+X8msTmVa7njthW3kwFJU1/K X-Received: from jonathantanmy0.svl.corp.google.com ([2620:15c:2d3:204:a487:6e54:d296:9521]) (user=jonathantanmy job=sendgmr) by 2002:a25:5016:0:b0:d15:fc00:fc69 with SMTP id e22-20020a255016000000b00d15fc00fc69mr95475ybb.9.1690915309595; Tue, 01 Aug 2023 11:41:49 -0700 (PDT) Date: Tue, 1 Aug 2023 11:41:36 -0700 In-Reply-To: Mime-Version: 1.0 References: X-Mailer: git-send-email 2.41.0.585.gd2178a4bd4-goog Message-ID: <3ce6090a4d3634b2e947d57f06714182207bb33a.1690912539.git.jonathantanmy@google.com> Subject: [PATCH v7 1/7] gitformat-commit-graph: describe version 2 of BDAT From: Jonathan Tan To: git@vger.kernel.org Cc: Jonathan Tan , Junio C Hamano , Taylor Blau Content-Type: text/plain; charset="UTF-8" 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 --- 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 -- 2.41.0.585.gd2178a4bd4-goog