git-commit-vandalism/builtin
Matheus Tavares f1928f04b2 grep: use no. of cores as the default no. of threads
When --threads is not specified, git-grep will use 8 threads by default.
This fixed number may be too many for machines with fewer cores and too
little for machines with more cores. So, instead, use the number of
logical cores available in the machine, which seems to result in the
best overall performance: The following measurements correspond to the
mean elapsed times for 30 git-grep executions in chromium's
repository[1] with a 95% confidence interval (each set of 30 were
performed after 2 warmup runs). Regex 1 is 'abcd[02]' and Regex 2 is
'(static|extern) (int|double) \*'.

      |          Working tree         |           Object Store
------|-------------------------------|--------------------------------
 #ths |  Regex 1      |  Regex 2      |   Regex 1      |   Regex 2
------|---------------|---------------|----------------|---------------
  32  |  2.92s ± 0.01 |  3.72s ± 0.21 |   5.36s ± 0.01 |   6.07s ± 0.01
  16  |  2.84s ± 0.01 |  3.57s ± 0.21 |   5.05s ± 0.01 |   5.71s ± 0.01
>  8  |  2.53s ± 0.00 |  3.24s ± 0.21 |   4.86s ± 0.01 |   5.48s ± 0.01
   4  |  2.43s ± 0.02 |  3.22s ± 0.20 |   5.22s ± 0.02 |   6.03s ± 0.02
   2  |  3.06s ± 0.20 |  4.52s ± 0.01 |   7.52s ± 0.01 |   9.06s ± 0.01
   1  |  6.16s ± 0.01 |  9.25s ± 0.02 |  14.10s ± 0.01 |  17.22s ± 0.01

The above tests were performed in a desktop running Debian 10.0 with
Intel(R) Xeon(R) CPU E3-1230 V2 (4 cores w/ hyper-threading), 32GB of
RAM and a 7200 rpm, SATA 3.1 HDD.

Bellow, the tests were repeated for a machine with SSD: a Manjaro laptop
with Intel(R) i7-7700HQ (4 cores w/ hyper-threading) and 16GB of RAM:

      |          Working tree          |           Object Store
------|--------------------------------|--------------------------------
 #ths |  Regex 1      |  Regex 2       |   Regex 1      |   Regex 2
------|---------------|----------------|----------------|---------------
  32  |  3.29s ± 0.21 |   4.30s ± 0.01 |   6.30s ± 0.01 |   7.30s ± 0.02
  16  |  3.19s ± 0.20 |   4.14s ± 0.02 |   5.91s ± 0.01 |   6.83s ± 0.01
>  8  |  2.90s ± 0.04 |   3.82s ± 0.20 |   5.70s ± 0.02 |   6.53s ± 0.01
   4  |  2.84s ± 0.02 |   3.77s ± 0.20 |   6.19s ± 0.02 |   7.18s ± 0.02
   2  |  3.73s ± 0.21 |   5.57s ± 0.02 |   9.28s ± 0.01 |  11.22s ± 0.01
   1  |  7.48s ± 0.02 |  11.36s ± 0.03 |  17.75s ± 0.01 |  21.87s ± 0.08

[1]: chromium’s repo at commit 03ae96f (“Add filters testing at DSF=2”,
     04-06-2019), after a 'git gc' execution.

Signed-off-by: Matheus Tavares <matheus.bernardino@usp.br>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-01-17 13:52:15 -08:00
..
add.c Merge branch 'js/add-p-in-c' 2019-12-25 11:22:01 -08:00
am.c Merge branch 'en/merge-recursive-cleanup' 2019-10-15 13:47:59 +09:00
annotate.c annotate: use argv_array 2014-07-16 11:10:11 -07:00
apply.c apply.c: make init_apply_state() take a struct repository 2018-08-13 14:14:44 -07:00
archive.c
bisect--helper.c Merge branch 'mr/bisect-save-pointer-to-const-string' 2019-12-25 11:22:01 -08:00
blame.c Merge branch 'sg/blame-indent-heuristics-is-now-the-default' 2019-12-01 09:04:30 -08:00
branch.c l10n: minor case fix in 'git branch' '--unset-upstream' description 2019-12-09 12:30:55 -08:00
bundle.c bundle-verify: add --quiet 2019-11-11 11:46:29 +09:00
cat-file.c Merge branch 'cc/multi-promisor' 2019-09-18 11:50:09 -07:00
check-attr.c
check-ignore.c treewide: rename 'exclude' methods to 'pattern' 2019-09-05 14:05:12 -07:00
check-mailmap.c
check-ref-format.c
checkout-index.c
checkout.c checkout, restore: support the --pathspec-from-file option 2019-12-04 10:10:37 -08:00
clean.c Merge branch 'en/clean-nested-with-ignored' 2019-10-11 14:24:46 +09:00
clone.c Merge branch 'ds/sparse-cone' 2019-12-25 11:21:58 -08:00
column.c builtin: consistently pass cmd_* prefix to parse_options 2019-05-13 14:22:53 +09:00
commit-graph.c test-tool: use 'read-graph' helper 2019-11-13 11:14:16 +09:00
commit-tree.c commit-tree: utilize parse-options api 2019-03-08 10:31:24 +09:00
commit.c Merge branch 'am/pathspec-from-file' 2019-12-25 11:21:57 -08:00
config.c
count-objects.c
credential.c
describe.c Merge branch 'ew/hashmap' 2019-10-15 13:48:02 +09:00
diff-files.c
diff-index.c cache.h: flip NO_THE_INDEX_COMPATIBILITY_MACROS switch 2019-01-24 11:55:06 -08:00
diff-tree.c
diff.c Merge branch 'nd/diff-parseopt-4' 2019-04-25 16:41:12 +09:00
difftool.c hashmap: remove type arg from hashmap_{get,put,remove}_entry 2019-10-07 10:20:12 +09:00
env--helper.c env--helper: mark a file-local symbol as static 2019-07-11 14:31:04 -07:00
fast-export.c Merge branch 'ew/hashmap' 2019-10-15 13:48:02 +09:00
fetch-pack.c fetch_pack(): drop unused parameters 2019-03-20 18:34:09 +09:00
fetch.c Merge branch 'ds/commit-graph-set-size-mult' 2020-01-06 14:17:51 -08:00
fmt-merge-msg.c Merge branch 'hi/gpg-use-check-signature' 2019-12-10 13:11:45 -08:00
for-each-ref.c parse_opt_ref_sorting: always use with NONEG flag 2019-03-21 12:03:35 +09:00
fsck.c fsck: only provide oid/type in fsck_error callback 2019-10-28 14:05:18 +09:00
gc.c Fix spelling errors in code comments 2019-11-10 16:00:54 +09:00
get-tar-commit-id.c builtin/get-tar-commit-id: make hash size independent 2019-04-01 11:57:39 +09:00
grep.c grep: use no. of cores as the default no. of threads 2020-01-17 13:52:15 -08:00
hash-object.c builtin: consistently pass cmd_* prefix to parse_options 2019-05-13 14:22:53 +09:00
help.c completion: add more parameter value completion 2019-02-20 12:31:56 -08:00
index-pack.c Merge branch 'bc/object-id-part17' 2019-10-11 14:24:46 +09:00
init-db.c Merge branch 'nd/init-relative-template-fix' into maint 2019-07-25 14:27:06 -07:00
interpret-trailers.c interpret-trailers: load default config 2019-06-19 07:12:49 -07:00
log.c Merge branch 'dl/format-patch-notes-config-fixup' 2019-12-25 11:21:58 -08:00
ls-files.c Merge branch 'ds/include-exclude' 2019-09-30 13:19:32 +09:00
ls-remote.c parse_opt_ref_sorting: always use with NONEG flag 2019-03-21 12:03:35 +09:00
ls-tree.c
mailinfo.c
mailsplit.c
merge-base.c
merge-file.c
merge-index.c
merge-ours.c
merge-recursive.c Ensure index matches head before invoking merge machinery, round N 2019-08-19 10:08:03 -07:00
merge-tree.c Merge branch 'jk/tree-walk-overflow' 2019-08-22 12:34:10 -07:00
merge.c Merge branch 'tg/stash-refresh-index' 2019-10-07 11:32:53 +09:00
mktag.c
mktree.c mktree: drop unused length parameter 2019-05-13 14:22:54 +09:00
multi-pack-index.c multi-pack-index: add [--[no-]progress] option. 2019-10-23 12:05:06 +09:00
mv.c
name-rev.c Merge branch 'sg/name-rev-wo-recursion' 2019-12-25 11:21:58 -08:00
notes.c notes: fix minimum number of parameters to "copy" subcommand 2019-10-18 09:43:10 +09:00
pack-objects.c Fix spelling errors in code comments 2019-11-10 16:00:54 +09:00
pack-redundant.c object-store: rename and expand packed_git's sha1 member 2019-04-01 11:57:38 +09:00
pack-refs.c Honor core.precomposeUnicode in more places 2019-04-26 10:54:03 +09:00
patch-id.c patch-id: use oid_to_hex() to print multiple object IDs 2019-12-09 12:26:40 -08:00
prune-packed.c
prune.c object: convert lookup_object() to use object_id 2019-06-20 10:18:09 -07:00
pull.c pull, fetch: add --set-upstream option 2019-08-19 13:05:58 -07:00
push.c push: use skip_prefix() instead of starts_with() 2019-11-27 11:18:39 +09:00
range-diff.c range-diff: clear other_arg at end of function 2019-12-06 12:36:53 -08:00
read-tree.c sparse-checkout: update working directory in-process 2019-11-22 16:11:44 +09:00
rebase.c Revert "Merge branch 'ra/rebase-i-more-options'" 2020-01-12 13:25:18 -08:00
receive-pack.c builtin/receive-pack: replace sha1_to_hex 2019-08-19 15:04:59 -07:00
reflog.c
remote-ext.c
remote-fd.c
remote.c remote: pass NULL to read_ref_full() because object ID is not needed 2019-12-11 13:48:46 -08:00
repack.c Merge branch 'wb/midx-progress' 2019-11-10 18:02:14 +09:00
replace.c Merge branch 'bc/object-id-part17' 2019-10-11 14:24:46 +09:00
rerere.c
reset.c Merge branch 'am/pathspec-from-file' 2019-12-10 13:11:41 -08:00
rev-list.c Merge branch 'rs/dedup-includes' 2019-10-11 14:24:48 +09:00
rev-parse.c rev-parse: make --show-toplevel without a worktree an error 2019-11-20 10:19:58 +09:00
revert.c Merge branch 'ra/cherry-pick-revert-skip' 2019-07-19 11:30:21 -07:00
rm.c Merge branch 'jc/denoise-rm-to-resolve' into maint 2019-07-29 12:38:17 -07:00
send-pack.c
shortlog.c
show-branch.c show-branch: drop unused parameter from show_independent() 2019-05-13 14:22:54 +09:00
show-index.c builtin/show-index: replace sha1_to_hex 2019-08-19 15:04:59 -07:00
show-ref.c Merge branch 'en/unicode-in-refnames' 2019-05-19 16:45:30 +09:00
sparse-checkout.c sparse-checkout: list directories in cone mode 2019-12-30 09:07:18 -08:00
stash.c Merge branch 'tg/stash-refresh-index' 2019-12-01 09:04:37 -08:00
stripspace.c
submodule--helper.c Merge branch 'jt/clone-recursesub-ref-advise' 2019-12-10 13:11:43 -08:00
symbolic-ref.c
tag.c tag: add tag.gpgSign config option to force all tags be GPG-signed 2019-06-05 14:39:28 -07:00
unpack-file.c
unpack-objects.c builtin/unpack-objects.c: show throughput progress 2019-11-20 10:30:18 +09:00
update-index.c Merge branch 'js/update-index-ignore-removal-for-skip-worktree' 2019-11-10 18:02:16 +09:00
update-ref.c
update-server-info.c parse-options: let OPT__FORCE take optional flags argument 2018-02-09 10:24:50 -08:00
upload-archive.c
upload-pack.c builtin: consistently pass cmd_* prefix to parse_options 2019-05-13 14:22:53 +09:00
var.c config: don't include config.h by default 2017-06-15 12:56:22 -07:00
verify-commit.c Merge branch 'jk/no-system-includes-in-dot-c' 2019-07-31 14:38:56 -07:00
verify-pack.c
verify-tag.c verify-tag: drop signal.h include 2019-06-19 08:19:21 -07:00
worktree.c Merge branch 'pb/no-recursive-reset-hard-in-worktree-add' 2019-12-01 09:04:31 -08:00
write-tree.c cmd_{read,write}_tree: rename "unused" variable that is used 2019-05-13 14:22:53 +09:00