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-Status: No, score=-3.7 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,SPF_HELO_PASS, SPF_PASS shortcircuit=no autolearn=ham autolearn_force=no version=3.4.2 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by dcvr.yhbt.net (Postfix) with ESMTP id 0D62A1F5AE for ; Mon, 15 Jun 2020 20:15:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731156AbgFOUPG (ORCPT ); Mon, 15 Jun 2020 16:15:06 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35102 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731104AbgFOUPB (ORCPT ); Mon, 15 Jun 2020 16:15:01 -0400 Received: from mail-wr1-x444.google.com (mail-wr1-x444.google.com [IPv6:2a00:1450:4864:20::444]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6CE17C05BD43 for ; Mon, 15 Jun 2020 13:15:00 -0700 (PDT) Received: by mail-wr1-x444.google.com with SMTP id e1so18479954wrt.5 for ; Mon, 15 Jun 2020 13:15:00 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=message-id:in-reply-to:references:from:date:subject:mime-version :content-transfer-encoding:fcc:to:cc; bh=Q8Ed7Syi5EhU0989HD8NNIjYtThDtCQRHO2L6h1zz4I=; b=DURA7GudkRw7UJ2Wu681wZbxLSVW03nj09xDMR9NnJS6/GZFKV6zW0URwVhiDAw551 KNTOdog2UHBIRaJzwvxQsThydaPcLOkBMQfSPLQh1IhywwOHp4tzbj/urHvU5lQjajHz yrKbni5WskBMx/xQkXgP20fHvTxl9Wdp6HTw9zcU8trfW8j6/H3jAbu4chBhut0vb+Ey O/fVYdnsb4Uwj7VNBhaoGL0eHU3o3H75TKS5eLGMvDO6PfXQn9BhnB53CGqDgf/cJ1XO P03gO2I+CBXzE3EH04BXL2CesWlC6CkADgSSiu1yFPpSFptKJm4wJ++xFrujHqPBJvvi ElfQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:message-id:in-reply-to:references:from:date :subject:mime-version:content-transfer-encoding:fcc:to:cc; bh=Q8Ed7Syi5EhU0989HD8NNIjYtThDtCQRHO2L6h1zz4I=; b=CFqC5YfYWYvnD98dQSL4IAI+tiSMqOo8tOZGNz5eoGrePN7fAjN1Rs6kjASGOkhDXj 5Fdo6KHk+FGurGcaIUmfJrkRanaNVh9RxVZoeAeA5oq9jgJcuxYThe2KeEU3611PvcQn sIk0Qt9TyEzpLn9rJnFfIwgdiFnDQ6kLoakgDFi7GhANYX9EkQsjW+vqBiTr133B2QDi N+ic44CC2nfoMyulzZ/im65ANu4Kqof/5Y/tonWFHTKoj3O59r1/C40qeYWgVLgWRDMb oIC85P5wXuPX36vPEUaZCko55mlBF7HvxJspjsllMC8zPlGre4bTIhJ1H5cyIM7OS5O+ wFGg== X-Gm-Message-State: AOAM5300ikIdBNTqP72mBbNeVHt4iI7YG2hvrFBKNcEi2XYsq+xE22sI 3Sd4FpO8bRNj36oTDMju9wcu2eqX X-Google-Smtp-Source: ABdhPJxtnt60RRRI75sI5Uk7hdavhuh30cfzv/7MBsPXDY3AxSy8xUlZAni3LndlWg5HpEZu9Q1U4A== X-Received: by 2002:a5d:654c:: with SMTP id z12mr30062364wrv.315.1592252098972; Mon, 15 Jun 2020 13:14:58 -0700 (PDT) Received: from [127.0.0.1] ([13.74.141.28]) by smtp.gmail.com with ESMTPSA id v66sm882579wme.13.2020.06.15.13.14.58 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 15 Jun 2020 13:14:58 -0700 (PDT) Message-Id: <9975fc96f1269b049ebdd54835a63480c3dcbe4e.1592252093.git.gitgitgadget@gmail.com> In-Reply-To: References: From: "=?UTF-8?q?SZEDER=20G=C3=A1bor?= via GitGitGadget" Date: Mon, 15 Jun 2020 20:14:50 +0000 Subject: [PATCH 5/8] commit-graph: check all leading directories in changed path Bloom filters MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Fcc: Sent To: git@vger.kernel.org Cc: me@ttaylorr.com, szeder.dev@gmail.com, Derrick Stolee , =?UTF-8?q?SZEDER=20G=C3=A1bor?= Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org From: =?UTF-8?q?SZEDER=20G=C3=A1bor?= The file 'dir/subdir/file' can only be modified if its leading directories 'dir' and 'dir/subdir' are modified as well. So when checking modified path Bloom filters looking for commits modifying a path with multiple path components, then check not only the full path in the Bloom filters, but all its leading directories as well. Take care to check these paths in "deepest first" order, because it's the full path that is least likely to be modified, and the Bloom filter queries can short circuit sooner. This can significantly reduce the average false positive rate, by about an order of magnitude or three(!), and can further speed up pathspec-limited revision walks. The table below compares the average false positive rate and runtime of git rev-list HEAD -- "$path" before and after this change for 5000+ randomly* selected paths from each repository: Average false Average Average positive rate runtime runtime before after before after difference ------------------------------------------------------------------ git 3.220% 0.7853% 0.0558s 0.0387s -30.6% linux 2.453% 0.0296% 0.1046s 0.0766s -26.8% tensorflow 2.536% 0.6977% 0.0594s 0.0420s -29.2% *Path selection was done with the following pipeline: git ls-tree -r --name-only HEAD | sort -R | head -n 5000 The improvements in runtime are much smaller than the improvements in average false positive rate, as we are clearly reaching diminishing returns here. However, all these timings depend on that accessing tree objects is reasonably fast (warm caches). If we had a partial clone and the tree objects had to be fetched from a promisor remote, e.g.: $ git clone --filter=tree:0 --bare file://.../webkit.git webkit.notrees.git $ git -C webkit.git -c core.modifiedPathBloomFilters=1 \ commit-graph write --reachable $ cp webkit.git/objects/info/commit-graph webkit.notrees.git/objects/info/ $ git -C webkit.notrees.git -c core.modifiedPathBloomFilters=1 \ rev-list HEAD -- "$path" then checking all leading path component can reduce the runtime from over an hour to a few seconds (and this is with the clone and the promisor on the same machine). This adjusts the tracing values in t4216-log-bloom.sh, which provides a concrete way to notice the improvement. Signed-off-by: SZEDER Gábor Signed-off-by: Derrick Stolee --- revision.c | 35 ++++++++++++++++++++++++++--------- revision.h | 6 ++++-- t/t4216-log-bloom.sh | 2 +- 3 files changed, 31 insertions(+), 12 deletions(-) diff --git a/revision.c b/revision.c index c644c660917..027ae3982b4 100644 --- a/revision.c +++ b/revision.c @@ -670,9 +670,10 @@ static void prepare_to_use_bloom_filter(struct rev_info *revs) { struct pathspec_item *pi; char *path_alloc = NULL; - const char *path; + const char *path, *p; int last_index; - int len; + size_t len; + int path_component_nr = 0, j; if (!revs->commits) return; @@ -705,8 +706,22 @@ static void prepare_to_use_bloom_filter(struct rev_info *revs) len = strlen(path); - revs->bloom_key = xmalloc(sizeof(struct bloom_key)); - fill_bloom_key(path, len, revs->bloom_key, revs->bloom_filter_settings); + p = path; + do { + p = strchrnul(p + 1, '/'); + path_component_nr++; + } while (p - path < len); + + revs->bloom_keys_nr = path_component_nr; + ALLOC_ARRAY(revs->bloom_keys, revs->bloom_keys_nr); + + p = path; + for (j = 0; j < revs->bloom_keys_nr; j++) { + p = strchrnul(p + 1, '/'); + + fill_bloom_key(path, p - path, &revs->bloom_keys[j], + revs->bloom_filter_settings); + } if (trace2_is_enabled() && !bloom_filter_atexit_registered) { atexit(trace2_bloom_filter_statistics_atexit); @@ -720,7 +735,7 @@ static int check_maybe_different_in_bloom_filter(struct rev_info *revs, struct commit *commit) { struct bloom_filter *filter; - int result; + int result = 1, j; if (!revs->repo->objects->commit_graph) return -1; @@ -740,9 +755,11 @@ static int check_maybe_different_in_bloom_filter(struct rev_info *revs, return -1; } - result = bloom_filter_contains(filter, - revs->bloom_key, - revs->bloom_filter_settings); + for (j = 0; result && j < revs->bloom_keys_nr; j++) { + result = bloom_filter_contains(filter, + &revs->bloom_keys[j], + revs->bloom_filter_settings); + } if (result) count_bloom_filter_maybe++; @@ -782,7 +799,7 @@ static int rev_compare_tree(struct rev_info *revs, return REV_TREE_SAME; } - if (revs->bloom_key && !nth_parent) { + if (revs->bloom_keys_nr && !nth_parent) { bloom_ret = check_maybe_different_in_bloom_filter(revs, commit); if (bloom_ret == 0) diff --git a/revision.h b/revision.h index 7c026fe41fc..abbfb4ab59a 100644 --- a/revision.h +++ b/revision.h @@ -295,8 +295,10 @@ struct rev_info { struct topo_walk_info *topo_walk_info; /* Commit graph bloom filter fields */ - /* The bloom filter key for the pathspec */ - struct bloom_key *bloom_key; + /* The bloom filter key(s) for the pathspec */ + struct bloom_key *bloom_keys; + int bloom_keys_nr; + /* * The bloom filter settings used to generate the key. * This is loaded from the commit-graph being used. diff --git a/t/t4216-log-bloom.sh b/t/t4216-log-bloom.sh index c7011f33e2c..c13b97d3bda 100755 --- a/t/t4216-log-bloom.sh +++ b/t/t4216-log-bloom.sh @@ -142,7 +142,7 @@ test_expect_success 'setup - add commit-graph to the chain with Bloom filters' ' test_bloom_filters_used_when_some_filters_are_missing () { log_args=$1 - bloom_trace_prefix="statistics:{\"filter_not_present\":3,\"zero_length_filter\":0,\"maybe\":8,\"definitely_not\":6" + bloom_trace_prefix="statistics:{\"filter_not_present\":3,\"zero_length_filter\":0,\"maybe\":6,\"definitely_not\":8" setup "$log_args" && grep -q "$bloom_trace_prefix" "$TRASH_DIRECTORY/trace.perf" && test_cmp log_wo_bloom log_w_bloom -- gitgitgadget