diff options
author | Junio C Hamano <gitster@pobox.com> | 2016-10-28 19:01:17 +0300 |
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committer | Junio C Hamano <gitster@pobox.com> | 2016-10-28 19:01:17 +0300 |
commit | 39000e849970a554a257577dcb2fb844a523a1d1 (patch) | |
tree | 26911732b4cb4f2c6389cbb7bbfb437c9e406025 /t | |
parent | 96ec83ce5207be0aac3c1df1ac92356f9de9ad81 (diff) | |
parent | 5827a03545663f6d6b491a35edb313900608568b (diff) |
Merge branch 'jk/fetch-quick-tag-following' into maint
When fetching from a remote that has many tags that are irrelevant
to branches we are following, we used to waste way too many cycles
when checking if the object pointed at by a tag (that we are not
going to fetch!) exists in our repository too carefully.
* jk/fetch-quick-tag-following:
fetch: use "quick" has_sha1_file for tag following
Diffstat (limited to 't')
-rwxr-xr-x | t/perf/p5550-fetch-tags.sh | 99 |
1 files changed, 99 insertions, 0 deletions
diff --git a/t/perf/p5550-fetch-tags.sh b/t/perf/p5550-fetch-tags.sh new file mode 100755 index 0000000000..a5dc39f86a --- /dev/null +++ b/t/perf/p5550-fetch-tags.sh @@ -0,0 +1,99 @@ +#!/bin/sh + +test_description='performance of tag-following with many tags + +This tests a fairly pathological case, so rather than rely on a real-world +case, we will construct our own repository. The situation is roughly as +follows. + +The parent repository has a large number of tags which are disconnected from +the rest of history. That makes them candidates for tag-following, but we never +actually grab them (and thus they will impact each subsequent fetch). + +The child repository is a clone of parent, without the tags, and is at least +one commit behind the parent (meaning that we will fetch one object and then +examine the tags to see if they need followed). Furthermore, it has a large +number of packs. + +The exact values of "large" here are somewhat arbitrary; I picked values that +start to show a noticeable performance problem on my machine, but without +taking too long to set up and run the tests. +' +. ./perf-lib.sh + +# make a long nonsense history on branch $1, consisting of $2 commits, each +# with a unique file pointing to the blob at $2. +create_history () { + perl -le ' + my ($branch, $n, $blob) = @ARGV; + for (1..$n) { + print "commit refs/heads/$branch"; + print "committer nobody <nobody@example.com> now"; + print "data 4"; + print "foo"; + print "M 100644 $blob $_"; + } + ' "$@" | + git fast-import --date-format=now +} + +# make a series of tags, one per commit in the revision range given by $@ +create_tags () { + git rev-list "$@" | + perl -lne 'print "create refs/tags/$. $_"' | + git update-ref --stdin +} + +# create $1 nonsense packs, each with a single blob +create_packs () { + perl -le ' + my ($n) = @ARGV; + for (1..$n) { + print "blob"; + print "data <<EOF"; + print "$_"; + print "EOF"; + } + ' "$@" | + git fast-import && + + git cat-file --batch-all-objects --batch-check='%(objectname)' | + while read sha1 + do + echo $sha1 | git pack-objects .git/objects/pack/pack + done +} + +test_expect_success 'create parent and child' ' + git init parent && + git -C parent commit --allow-empty -m base && + git clone parent child && + git -C parent commit --allow-empty -m trigger-fetch +' + +test_expect_success 'populate parent tags' ' + ( + cd parent && + blob=$(echo content | git hash-object -w --stdin) && + create_history cruft 3000 $blob && + create_tags cruft && + git branch -D cruft + ) +' + +test_expect_success 'create child packs' ' + ( + cd child && + git config gc.auto 0 && + git config gc.autopacklimit 0 && + create_packs 500 + ) +' + +test_perf 'fetch' ' + # make sure there is something to fetch on each iteration + git -C child update-ref -d refs/remotes/origin/master && + git -C child fetch +' + +test_done |