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| author |  Jeff Hostetler <jeffhost@microsoft.com> | 2017-02-09 23:27:49 +0100 |
|---|---|---|
| committer |  Junio C Hamano <gitster@pobox.com> | 2017-02-09 15:40:06 -0800 |
| commit | 2cfc70f0de7c8902791d3b23a92d6462b9e11d72 (patch) | |
| tree | 8f16a18b996d5b79311e3326ce467f05c20b8870 /Documentation/technical/api-trace.txt | |
| parent | Git 2.11.1 (diff) | |
| download | tgif-2cfc70f0de7c8902791d3b23a92d6462b9e11d72.tar.xz | |
mingw: use OpenSSL's SHA-1 routines
Use OpenSSL's SHA-1 routines rather than builtin block-sha1 routines.
This improves performance on SHA1 operations on Intel processors.
OpenSSL 1.0.2 has made considerable performance improvements and
support the Intel hardware acceleration features. See:
https://software.intel.com/en-us/articles/improving-openssl-performance
https://software.intel.com/en-us/articles/intel-sha-extensions
To test this I added/staged a single file in a gigantic
repository having a 450MB index file. The code in read-cache.c
verifies the header SHA as it reads the index and computes a new
header SHA as it writes out the new index. Therefore, in this test
the SHA code must process 900MB of data. Testing was done on an
Intel I7-4770 CPU @ 3.40GHz (Intel64, Family 6, Model 60) CPU.
The block-sha1 version averaged 5.27 seconds.
The OpenSSL version averaged 4.50 seconds.
================================================================
$ echo xxx >> project.mk
$ time /e/blk_sha/bin/git.exe add project.mk
real 0m5.207s
user 0m0.000s
sys 0m0.250s
$ echo xxx >> project.mk
$ time /e/blk_sha/bin/git.exe add project.mk
real 0m5.362s
user 0m0.015s
sys 0m0.234s
$ echo xxx >> project.mk
$ time /e/blk_sha/bin/git.exe add project.mk
real 0m5.300s
user 0m0.016s
sys 0m0.250s
$ echo xxx >> project.mk
$ time /e/blk_sha/bin/git.exe add project.mk
real 0m5.216s
user 0m0.000s
sys 0m0.250s
================================================================
$ echo xxx >> project.mk
$ time /e/openssl/bin/git.exe add project.mk
real 0m4.431s
user 0m0.000s
sys 0m0.250s
$ echo xxx >> project.mk
$ time /e/openssl/bin/git.exe add project.mk
real 0m4.478s
user 0m0.000s
sys 0m0.265s
$ echo xxx >> project.mk
$ time /e/openssl/bin/git.exe add project.mk
real 0m4.690s
user 0m0.000s
sys 0m0.250s
$ echo xxx >> project.mk
$ time /e/openssl/bin/git.exe add project.mk
real 0m4.420s
user 0m0.000s
sys 0m0.234s
================================================================
Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Diffstat (limited to 'Documentation/technical/api-trace.txt')
0 files changed, 0 insertions, 0 deletions