summaryrefslogtreecommitdiff
path: root/t/perf/p5310-pack-bitmaps.sh
diff options
context:
space:
mode:
authorJeff King <peff@peff.net>2013-12-21 14:00:42 (GMT)
committerJunio C Hamano <gitster@pobox.com>2013-12-30 20:19:23 (GMT)
commitbbcefa1f3f8355921137dd7a097b3ee3db66f023 (patch)
tree99c6e9e4bc6b5de153e0433d4d8839baf55de615 /t/perf/p5310-pack-bitmaps.sh
parent212f2ffbf0331ceca1a4bc1820ab1ac5c5115e8b (diff)
downloadgit-bbcefa1f3f8355921137dd7a097b3ee3db66f023.zip
git-bbcefa1f3f8355921137dd7a097b3ee3db66f023.tar.gz
git-bbcefa1f3f8355921137dd7a097b3ee3db66f023.tar.bz2
t/perf: add tests for pack bitmaps
This adds a few basic perf tests for the pack bitmap code to show off its improvements. The tests are: 1. How long does it take to do a repack (it gets slower with bitmaps, since we have to do extra work)? 2. How long does it take to do a clone (it gets faster with bitmaps)? 3. How does a small fetch perform when we've just repacked? 4. How does a clone perform when we haven't repacked since a week of pushes? Here are results against linux.git: Test origin/master this tree ----------------------------------------------------------------------- 5310.2: repack to disk 33.64(32.64+2.04) 67.67(66.75+1.84) +101.2% 5310.3: simulated clone 30.49(29.47+2.05) 1.20(1.10+0.10) -96.1% 5310.4: simulated fetch 3.49(6.79+0.06) 5.57(22.35+0.07) +59.6% 5310.6: partial bitmap 36.70(43.87+1.81) 8.18(21.92+0.73) -77.7% You can see that we do take longer to repack, but we do way better for further clones. A small fetch performs a bit worse, as we spend way more time on delta compression (note the heavy user CPU time, as we have 8 threads) due to the lack of name hashes for the bitmapped objects. The final test shows how the bitmaps degrade over time between packs. There's still a significant speedup over the non-bitmap case, but we don't do quite as well (we have to spend time accessing the "new" objects the old fashioned way, including delta compression). Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Diffstat (limited to 't/perf/p5310-pack-bitmaps.sh')
-rwxr-xr-xt/perf/p5310-pack-bitmaps.sh56
1 files changed, 56 insertions, 0 deletions
diff --git a/t/perf/p5310-pack-bitmaps.sh b/t/perf/p5310-pack-bitmaps.sh
new file mode 100755
index 0000000..8c6ae45
--- /dev/null
+++ b/t/perf/p5310-pack-bitmaps.sh
@@ -0,0 +1,56 @@
+#!/bin/sh
+
+test_description='Tests pack performance using bitmaps'
+. ./perf-lib.sh
+
+test_perf_large_repo
+
+# note that we do everything through config,
+# since we want to be able to compare bitmap-aware
+# git versus non-bitmap git
+test_expect_success 'setup bitmap config' '
+ git config pack.writebitmaps true
+'
+
+test_perf 'repack to disk' '
+ git repack -ad
+'
+
+test_perf 'simulated clone' '
+ git pack-objects --stdout --all </dev/null >/dev/null
+'
+
+test_perf 'simulated fetch' '
+ have=$(git rev-list HEAD~100 -1) &&
+ {
+ echo HEAD &&
+ echo ^$have
+ } | git pack-objects --revs --stdout >/dev/null
+'
+
+test_expect_success 'create partial bitmap state' '
+ # pick a commit to represent the repo tip in the past
+ cutoff=$(git rev-list HEAD~100 -1) &&
+ orig_tip=$(git rev-parse HEAD) &&
+
+ # now kill off all of the refs and pretend we had
+ # just the one tip
+ rm -rf .git/logs .git/refs/* .git/packed-refs
+ git update-ref HEAD $cutoff
+
+ # and then repack, which will leave us with a nice
+ # big bitmap pack of the "old" history, and all of
+ # the new history will be loose, as if it had been pushed
+ # up incrementally and exploded via unpack-objects
+ git repack -Ad
+
+ # and now restore our original tip, as if the pushes
+ # had happened
+ git update-ref HEAD $orig_tip
+'
+
+test_perf 'partial bitmap' '
+ git pack-objects --stdout --all </dev/null >/dev/null
+'
+
+test_done