Enables threading in index-pack to resolve base data in parallel.
By Nguyễn Thái Ngọc Duy (3) and Ramsay Jones (1)
* nd/threaded-index-pack:
index-pack: disable threading if NO_PREAD is defined
index-pack: support multithreaded delta resolving
index-pack: restructure pack processing into three main functions
compat/win32/pthread.h: Add an pthread_key_delete() implementation
This puts delta resolving on each base on a separate thread, one base
cache per thread. Per-thread data is grouped in struct thread_local.
When running with nr_threads == 1, no pthreads calls are made. The
system essentially runs in non-thread mode.
An experiment on a Xeon 24 core machine with git.git shows that
performance does not increase proportional to the number of cores. So
by default, we use maximum 3 cores. Some numbers with --threads from 1
to 16:
1..4
real 0m8.003s 0m5.307s 0m4.321s 0m3.830s
user 0m7.720s 0m8.009s 0m8.133s 0m8.305s
sys 0m0.224s 0m0.372s 0m0.360s 0m0.360s
5..8
real 0m3.727s 0m3.604s 0m3.332s 0m3.369s
user 0m9.361s 0m9.817s 0m9.525s 0m9.769s
sys 0m0.584s 0m0.624s 0m0.540s 0m0.560s
9..12
real 0m3.036s 0m3.139s 0m3.177s 0m2.961s
user 0m8.977s 0m10.205s 0m9.737s 0m10.073s
sys 0m0.596s 0m0.680s 0m0.684s 0m0.680s
13..16
real 0m2.985s 0m2.894s 0m2.975s 0m2.971s
user 0m9.825s 0m10.573s 0m10.833s 0m11.361s
sys 0m0.788s 0m0.732s 0m0.904s 0m1.016s
On an Intel dual core and linux-2.6.git
1..4
real 2m37.789s 2m7.963s 2m0.920s 1m58.213s
user 2m28.415s 2m52.325s 2m50.176s 2m41.187s
sys 0m7.808s 0m11.181s 0m11.224s 0m10.731s
Thanks Ramsay Jones for troubleshooting and support on MinGW platform.
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The 'log -3000 (baseline)' test accidentally still used -1000 from an
earlier version.
Noticed-by: Lawrence Holding <Lawrence.Holding@cubic.com>
Signed-off-by: Thomas Rast <trast@student.ethz.ch>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The only bug right now is that $GIT_TEST_CMP is needed for test_cmp to
work.
However, we also export the three most important paths for tests:
TEST_DIRECTORY
TRASH_DIRECTORY
GIT_BUILD_DIR
Since they are available within test_expect_success, a future test
writer may expect them to also be defined in test_perf.
Signed-off-by: Thomas Rast <trast@student.ethz.ch>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Loading it in the subshells still referred to $TEST_DIRECTORY/..,
which was only correct in preliminary versions of perf-lib.sh
Signed-off-by: Thomas Rast <trast@student.ethz.ch>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
8c912ee (teach --histogram to diff, 2011-07-12) claimed histogram diff
was faster than both Myers and patience.
We have since incorporated a performance testing framework, so add a
test that compares the various diff tasks performed in a real 'log -p'
workload. This does indeed show that histogram diff slightly beats
Myers, while patience is much slower than the others.
Signed-off-by: Thomas Rast <trast@student.ethz.ch>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The only catch is that we don't really know what our repo contains, so
we have to ignore any possible "not found" status from git-grep.
Signed-off-by: Thomas Rast <trast@student.ethz.ch>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This introduces a performance testing framework under t/perf/. It
tries to be as close to the test-lib.sh infrastructure as possible,
and thus should be easy to get used to for git developers.
The following points were considered for the implementation:
1. You usually want to compare arbitrary revisions/build trees against
each other. They may not have the performance test under
consideration, or even the perf-lib.sh infrastructure.
To cope with this, the 'run' script lets you specify arbitrary
build dirs and revisions. It even automatically builds the revisions
if it doesn't have them at hand yet.
2. Usually you would not want to run all tests. It would take too
long anyway. The 'run' script lets you specify which tests to run;
or you can also do it manually. There is a Makefile for
discoverability and 'make clean', but it is not meant for
real-world use.
3. Creating test repos from scratch in every test is extremely
time-consuming, and shipping or downloading such large/weird repos
is out of the question.
We leave this decision to the user. Two different sizes of test
repos can be configured, and the scripts just copy one or more of
those (using hardlinks for the object store). By default it tries
to use the build tree's git.git repository.
This is fairly fast and versatile. Using a copy instead of a clone
preserves many properties that the user may want to test for, such
as lots of loose objects, unpacked refs, etc.
Signed-off-by: Thomas Rast <trast@student.ethz.ch>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
