From 809e0327f579267ea78a1b2f727d3b63c1f5d044 Mon Sep 17 00:00:00 2001 From: Taylor Blau Date: Fri, 18 Sep 2020 09:27:27 -0400 Subject: builtin/commit-graph.c: introduce '--max-new-filters=' Introduce a command-line flag to specify the maximum number of new Bloom filters that a 'git commit-graph write' is willing to compute from scratch. Prior to this patch, a commit-graph write with '--changed-paths' would compute Bloom filters for all selected commits which haven't already been computed (i.e., by a previous commit-graph write with '--split' such that a roll-up or replacement is performed). This behavior can cause prohibitively-long commit-graph writes for a variety of reasons: * There may be lots of filters whose diffs take a long time to generate (for example, they have close to the maximum number of changes, diffing itself takes a long time, etc). * Old-style commit-graphs (which encode filters with too many entries as not having been computed at all) cause us to waste time recomputing filters that appear to have not been computed only to discover that they are too-large. This can make the upper-bound of the time it takes for 'git commit-graph write --changed-paths' to be rather unpredictable. To make this command behave more predictably, introduce '--max-new-filters=' to allow computing at most '' Bloom filters from scratch. This lets "computing" already-known filters proceed quickly, while bounding the number of slow tasks that Git is willing to do. Helped-by: Junio C Hamano Signed-off-by: Taylor Blau Signed-off-by: Junio C Hamano --- Documentation/git-commit-graph.txt | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'Documentation/git-commit-graph.txt') diff --git a/Documentation/git-commit-graph.txt b/Documentation/git-commit-graph.txt index 17405c73a9..8c75855782 100644 --- a/Documentation/git-commit-graph.txt +++ b/Documentation/git-commit-graph.txt @@ -67,6 +67,12 @@ this option is given, future commit-graph writes will automatically assume that this option was intended. Use `--no-changed-paths` to stop storing this data. + +With the `--max-new-filters=` option, generate at most `n` new Bloom +filters (if `--changed-paths` is specified). If `n` is `-1`, no limit is +enforced. Only commits present in the new layer count against this +limit. To retroactively compute Bloom filters over earlier layers, it is +advised to use `--split=replace`. ++ With the `--split[=]` option, write the commit-graph as a chain of multiple commit-graph files stored in `/info/commit-graphs`. Commit-graph layers are merged based on the -- cgit v1.3 From d356d5debe56b1e43b5ca674c662a08f25176f05 Mon Sep 17 00:00:00 2001 From: Taylor Blau Date: Thu, 17 Sep 2020 22:59:57 -0400 Subject: commit-graph: introduce 'commitGraph.maxNewFilters' Introduce a configuration variable to specify a default value for the recently-introduce '--max-new-filters' option of 'git commit-graph write'. Helped-by: Junio C Hamano Signed-off-by: Taylor Blau Signed-off-by: Junio C Hamano --- Documentation/config/commitgraph.txt | 4 ++++ Documentation/git-commit-graph.txt | 3 ++- builtin/commit-graph.c | 14 ++++++++++++++ t/t4216-log-bloom.sh | 24 +++++++++++++++++++++++- 4 files changed, 43 insertions(+), 2 deletions(-) (limited to 'Documentation/git-commit-graph.txt') diff --git a/Documentation/config/commitgraph.txt b/Documentation/config/commitgraph.txt index cff0797b54..4582c39fc4 100644 --- a/Documentation/config/commitgraph.txt +++ b/Documentation/config/commitgraph.txt @@ -1,3 +1,7 @@ +commitGraph.maxNewFilters:: + Specifies the default value for the `--max-new-filters` option of `git + commit-graph write` (c.f., linkgit:git-commit-graph[1]). + commitGraph.readChangedPaths:: If true, then git will use the changed-path Bloom filters in the commit-graph file (if it exists, and they are present). Defaults to diff --git a/Documentation/git-commit-graph.txt b/Documentation/git-commit-graph.txt index 8c75855782..de6b6de230 100644 --- a/Documentation/git-commit-graph.txt +++ b/Documentation/git-commit-graph.txt @@ -71,7 +71,8 @@ With the `--max-new-filters=` option, generate at most `n` new Bloom filters (if `--changed-paths` is specified). If `n` is `-1`, no limit is enforced. Only commits present in the new layer count against this limit. To retroactively compute Bloom filters over earlier layers, it is -advised to use `--split=replace`. +advised to use `--split=replace`. Overrides the `commitGraph.maxNewFilters` +configuration. + With the `--split[=]` option, write the commit-graph as a chain of multiple commit-graph files stored in diff --git a/builtin/commit-graph.c b/builtin/commit-graph.c index 5df9b2ef80..988445abdf 100644 --- a/builtin/commit-graph.c +++ b/builtin/commit-graph.c @@ -181,6 +181,18 @@ static int write_option_max_new_filters(const struct option *opt, return 0; } +static int git_commit_graph_write_config(const char *var, const char *value, + void *cb) +{ + if (!strcmp(var, "commitgraph.maxnewfilters")) + write_opts.max_new_filters = git_config_int(var, value); + /* + * No need to fall-back to 'git_default_config', since this was already + * called in 'cmd_commit_graph()'. + */ + return 0; +} + static int graph_write(int argc, const char **argv) { struct string_list pack_indexes = STRING_LIST_INIT_NODUP; @@ -231,6 +243,8 @@ static int graph_write(int argc, const char **argv) trace2_cmd_mode("write"); + git_config(git_commit_graph_write_config, &opts); + argc = parse_options(argc, argv, NULL, builtin_commit_graph_write_options, builtin_commit_graph_write_usage, 0); diff --git a/t/t4216-log-bloom.sh b/t/t4216-log-bloom.sh index 48ab1b16a6..023031d587 100755 --- a/t/t4216-log-bloom.sh +++ b/t/t4216-log-bloom.sh @@ -325,13 +325,15 @@ test_expect_success 'Bloom generation is limited by --max-new-filters' ' ' test_expect_success 'Bloom generation backfills previously-skipped filters' ' + # Check specifying commitGraph.maxNewFilters over "git config" works. + test_config -C limits commitGraph.maxNewFilters 1 && ( cd limits && rm -f trace.event && GIT_TRACE2_EVENT="$(pwd)/trace.event" \ git commit-graph write --reachable --changed-paths \ - --split=replace --max-new-filters=1 && + --split=replace && test_filter_computed 1 trace.event && test_filter_not_computed 4 trace.event && test_filter_trunc_empty 0 trace.event && @@ -339,6 +341,26 @@ test_expect_success 'Bloom generation backfills previously-skipped filters' ' ) ' +test_expect_success '--max-new-filters overrides configuration' ' + git init override && + test_when_finished "rm -fr override" && + test_config -C override commitGraph.maxNewFilters 2 && + ( + cd override && + test_commit one && + test_commit two && + + rm -f trace.event && + GIT_TRACE2_EVENT="$(pwd)/trace.event" \ + git commit-graph write --reachable --changed-paths \ + --max-new-filters=1 && + test_filter_computed 1 trace.event && + test_filter_not_computed 1 trace.event && + test_filter_trunc_empty 0 trace.event && + test_filter_trunc_large 0 trace.event + ) +' + test_expect_success 'Bloom generation backfills empty commits' ' git init empty && test_when_finished "rm -fr empty" && -- cgit v1.3