git/list[1] front-page[2] threads[3] people[4] search[5] about
 

[PATCH v2 4/4] t/perf: add fsmonitor perf test for git diff

From
Nipunn Koorapati via GitGitGadget <gitgitgadget@gmail.com>
Date
Oct 19, 2020, 21:35 UTC
Message-ID
<f572e226bb5e4b67cc57f8d9d4732086f01190a2.1603143316.git.gitgitgadget@gmail.com>
In-Reply-To
<pull.756.v2.git.1603143316.gitgitgadget@gmail.com>
From: Nipunn Koorapati <nipunn@dropbox.com>

Results for the git-diff fsmonitor optimization in patch in the parent-rev (using a 400k file repo to test)

As you can see here - git diff with fsmonitor running is significantly better with this patch series (80% faster on my workload)!

GIT_PERF_LARGE_REPO=~/src/server ./run v2.29.0-rc1 . -- p7519-fsmonitor.sh

Test v2.29.0-rc1 this tree ----------------------------------------------------------------------------------------------------------------- 7519.2: status (fsmonitor=.git/hooks/fsmonitor-watchman) 1.46(0.82+0.64) 1.47(0.83+0.62) +0.7% 7519.3: status -uno (fsmonitor=.git/hooks/fsmonitor-watchman) 0.16(0.12+0.04) 0.17(0.12+0.05) +6.3% 7519.4: status -uall (fsmonitor=.git/hooks/fsmonitor-watchman) 1.36(0.73+0.62) 1.37(0.76+0.60) +0.7% 7519.5: diff (fsmonitor=.git/hooks/fsmonitor-watchman) 0.85(0.22+0.63) 0.14(0.10+0.05) -83.5% 7519.6: diff -- 0_files (fsmonitor=.git/hooks/fsmonitor-watchman) 0.12(0.08+0.05) 0.13(0.11+0.02) +8.3% 7519.7: diff -- 10_files (fsmonitor=.git/hooks/fsmonitor-watchman) 0.12(0.08+0.04) 0.13(0.09+0.04) +8.3% 7519.8: diff -- 100_files (fsmonitor=.git/hooks/fsmonitor-watchman) 0.12(0.07+0.05) 0.13(0.07+0.06) +8.3% 7519.9: diff -- 1000_files (fsmonitor=.git/hooks/fsmonitor-watchman) 0.12(0.09+0.04) 0.13(0.08+0.05) +8.3% 7519.10: diff -- 10000_files (fsmonitor=.git/hooks/fsmonitor-watchman) 0.14(0.09+0.05) 0.13(0.10+0.03) -7.1% 7519.12: status (fsmonitor=) 1.67(0.93+1.49) 1.67(0.99+1.42) +0.0% 7519.13: status -uno (fsmonitor=) 0.37(0.30+0.82) 0.37(0.33+0.79) +0.0% 7519.14: status -uall (fsmonitor=) 1.58(0.97+1.35) 1.57(0.86+1.45) -0.6% 7519.15: diff (fsmonitor=) 0.34(0.28+0.83) 0.34(0.27+0.83) +0.0% 7519.16: diff -- 0_files (fsmonitor=) 0.09(0.06+0.04) 0.09(0.08+0.02) +0.0% 7519.17: diff -- 10_files (fsmonitor=) 0.09(0.07+0.03) 0.09(0.06+0.05) +0.0% 7519.18: diff -- 100_files (fsmonitor=) 0.09(0.06+0.04) 0.09(0.06+0.04) +0.0% 7519.19: diff -- 1000_files (fsmonitor=) 0.09(0.06+0.04) 0.09(0.05+0.05) +0.0% 7519.20: diff -- 10000_files (fsmonitor=) 0.10(0.08+0.04) 0.10(0.06+0.05) +0.0%

I also added a benchmark for a tiny git diff workload w/ a pathspec. I see an approximately .02 second overhead added w/ and w/o fsmonitor

From looking at these results, I suspected that refresh_fsmonitor is already happening during git diff - independent of this patch series' optimization. Confirmed that suspicion by breaking on refresh_fsmonitor.

(gdb) bt [simplified] 0 refresh_fsmonitor at fsmonitor.c:176 1 ie_match_stat at read-cache.c:375 2 match_stat_with_submodule at diff-lib.c:237 4 builtin_diff_files at builtin/diff.c:260 5 cmd_diff at builtin/diff.c:541 6 run_builtin at git.c:450 7 handle_builtin at git.c:700 8 run_argv at git.c:767 9 cmd_main at git.c:898 10 main at common-main.c:52

Signed-off-by: Nipunn Koorapati <nipunn@dropbox.com>
---
 t/perf/p7519-fsmonitor.sh | 71 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 71 insertions(+)
diff --git a/t/perf/p7519-fsmonitor.sh b/t/perf/p7519-fsmonitor.sh
index 9313d4a51d..2b4803707f 100755
--- a/t/perf/p7519-fsmonitor.sh
+++ b/t/perf/p7519-fsmonitor.sh
@@ -115,6 +115,13 @@ test_expect_success "setup for fsmonitor" '
 
 	git config core.fsmonitor "$INTEGRATION_SCRIPT" &&
 	git update-index --fsmonitor &&
+	mkdir 1_file 10_files 100_files 1000_files 10000_files &&
+	for i in `seq 1 10`; do touch 10_files/$i; done &&
+	for i in `seq 1 100`; do touch 100_files/$i; done &&
+	for i in `seq 1 1000`; do touch 1000_files/$i; done &&
+	for i in `seq 1 10000`; do touch 10000_files/$i; done &&
+	git add 1_file 10_files 100_files 1000_files 10000_files &&
+	git commit -m "Add files" &&
 	git status  # Warm caches
 '
 
@@ -142,6 +149,38 @@ test_perf "status -uall (fsmonitor=$INTEGRATION_SCRIPT)" '
 	git status -uall
 '
 
+if test -n "$GIT_PERF_7519_DROP_CACHE"; then
+	test-tool drop-caches
+fi
+
+test_perf "diff (fsmonitor=$INTEGRATION_SCRIPT)" '
+	git diff
+'
+
+if test -n "$GIT_PERF_7519_DROP_CACHE"; then
+	test-tool drop-caches
+fi
+
+test_perf "diff -- 0_files (fsmonitor=$INTEGRATION_SCRIPT)" '
+	git diff -- 1_file
+'
+
+test_perf "diff -- 10_files (fsmonitor=$INTEGRATION_SCRIPT)" '
+	git diff -- 10_files
+'
+
+test_perf "diff -- 100_files (fsmonitor=$INTEGRATION_SCRIPT)" '
+	git diff -- 100_files
+'
+
+test_perf "diff -- 1000_files (fsmonitor=$INTEGRATION_SCRIPT)" '
+	git diff -- 1000_files
+'
+
+test_perf "diff -- 10000_files (fsmonitor=$INTEGRATION_SCRIPT)" '
+	git diff -- 10000_files
+'
+
 test_expect_success "setup without fsmonitor" '
 	unset INTEGRATION_SCRIPT &&
 	git config --unset core.fsmonitor &&
@@ -172,6 +211,38 @@ test_perf "status -uall (fsmonitor=$INTEGRATION_SCRIPT)" '
 	git status -uall
 '
 
+if test -n "$GIT_PERF_7519_DROP_CACHE"; then
+	test-tool drop-caches
+fi
+
+test_perf "diff (fsmonitor=$INTEGRATION_SCRIPT)" '
+	git diff
+'
+
+if test -n "$GIT_PERF_7519_DROP_CACHE"; then
+	test-tool drop-caches
+fi
+
+test_perf "diff -- 0_files (fsmonitor=$INTEGRATION_SCRIPT)" '
+	git diff -- 1_file
+'
+
+test_perf "diff -- 10_files (fsmonitor=$INTEGRATION_SCRIPT)" '
+	git diff -- 10_files
+'
+
+test_perf "diff -- 100_files (fsmonitor=$INTEGRATION_SCRIPT)" '
+	git diff -- 100_files
+'
+
+test_perf "diff -- 1000_files (fsmonitor=$INTEGRATION_SCRIPT)" '
+	git diff -- 1000_files
+'
+
+test_perf "diff -- 10000_files (fsmonitor=$INTEGRATION_SCRIPT)" '
+	git diff -- 10000_files
+'
+
 if test_have_prereq WATCHMAN
 then
 	watchman watch-del "$GIT_WORK_TREE" >/dev/null 2>&1 &&
-- 
gitgitgadget
Previous: Nipunn Koorapati via GitGitGadgetNext: Taylor Blau
Message 20 of 52 in “use fsmonitor data in git diff eliminating O(num_files) calls to lstat”
  1. 0/4 use fsmonitor data in git diff eliminating O(num_files) calls to lstatNipunn Koorapati via GitGitGadget, Oct 17, 2020
  2. 1/4 fsmonitor: use fsmonitor data in `git diff`Alex Vandiver via GitGitGadget, Oct 17, 2020
  3. Junio C HamanoOct 17, 2020
  4. Nipunn KoorapatiOct 18, 2020
  5. Taylor BlauOct 18, 2020
  6. Junio C HamanoOct 18, 2020
  7. Taylor BlauOct 18, 2020
  8. Junio C HamanoOct 19, 2020
  9. Taylor BlauOct 19, 2020
  10. Nipunn KoorapatiOct 19, 2020
  11. 2/4 t/perf/README: elaborate on output formatNipunn Koorapati via GitGitGadget, Oct 17, 2020
  12. 4/4 t/perf: add fsmonitor perf test for git diffNipunn Koorapati via GitGitGadget, Oct 17, 2020
  13. Junio C HamanoOct 17, 2020
  14. 3/4 t/perf/p7519-fsmonitor.sh: warm cache on first git statusNipunn Koorapati via GitGitGadget, Oct 17, 2020
  15. Taylor BlauOct 18, 2020
  16. 0/4 use fsmonitor data in git diff eliminating O(num_files) calls to lstatNipunn Koorapati via GitGitGadget, Oct 19, 2020
  17. 1/4 fsmonitor: use fsmonitor data in `git diff`Alex Vandiver via GitGitGadget, Oct 19, 2020
  18. 2/4 t/perf/README: elaborate on output formatNipunn Koorapati via GitGitGadget, Oct 19, 2020
  19. 3/4 t/perf/p7519-fsmonitor.sh: warm cache on first git statusNipunn Koorapati via GitGitGadget, Oct 19, 2020
  20. 4/4 t/perf: add fsmonitor perf test for git diffNipunn Koorapati via GitGitGadget, Oct 19, 2020
  21. Taylor BlauOct 19, 2020
  22. Taylor BlauOct 19, 2020
  23. Nipunn KoorapatiOct 19, 2020
  24. Taylor BlauOct 19, 2020
  25. Nipunn KoorapatiOct 19, 2020
  26. 0/7 use fsmonitor data in git diff eliminating O(num_files) calls to lstatNipunn Koorapati via GitGitGadget, Oct 19, 2020
  27. 3/7 t/perf/p7519-fsmonitor.sh: warm cache on first git statusNipunn Koorapati via GitGitGadget, Oct 19, 2020
  28. 1/7 fsmonitor: use fsmonitor data in `git diff`Alex Vandiver via GitGitGadget, Oct 19, 2020
  29. 2/7 t/perf/README: elaborate on output formatNipunn Koorapati via GitGitGadget, Oct 19, 2020
  30. 5/7 perf lint: check test-lint-shell-syntax in perf testsNipunn Koorapati via GitGitGadget, Oct 19, 2020
  31. Taylor BlauOct 20, 2020
  32. Junio C HamanoOct 20, 2020
  33. Taylor BlauOct 20, 2020
  34. Nipunn KoorapatiOct 20, 2020
  35. Nipunn KoorapatiOct 20, 2020
  36. 7/7 p7519-fsmonitor: add a git add benchmarkNipunn Koorapati via GitGitGadget, Oct 19, 2020
  37. Nipunn KoorapatiOct 19, 2020
  38. Taylor BlauOct 20, 2020
  39. 4/7 t/perf: add fsmonitor perf test for git diffNipunn Koorapati via GitGitGadget, Oct 19, 2020
  40. 6/7 p7519-fsmonitor: refactor to avoid code duplicationNipunn Koorapati via GitGitGadget, Oct 19, 2020
  41. Taylor BlauOct 20, 2020
  42. 0/7 use fsmonitor data in git diff eliminating O(num_files) calls to lstatNipunn Koorapati via GitGitGadget, Oct 20, 2020
  43. 1/7 fsmonitor: use fsmonitor data in `git diff`Alex Vandiver via GitGitGadget, Oct 20, 2020
  44. 2/7 t/perf/README: elaborate on output formatNipunn Koorapati via GitGitGadget, Oct 20, 2020
  45. 6/7 p7519-fsmonitor: refactor to avoid code duplicationNipunn Koorapati via GitGitGadget, Oct 20, 2020
  46. 3/7 t/perf/p7519-fsmonitor.sh: warm cache on first git statusNipunn Koorapati via GitGitGadget, Oct 20, 2020
  47. 5/7 perf lint: add make test-lint to perf testsNipunn Koorapati via GitGitGadget, Oct 20, 2020
  48. Taylor BlauOct 20, 2020
  49. Nipunn KoorapatiOct 20, 2020
  50. Taylor BlauOct 20, 2020
  51. 4/7 t/perf: add fsmonitor perf test for git diffNipunn Koorapati via GitGitGadget, Oct 20, 2020
  52. 7/7 p7519-fsmonitor: add a git add benchmarkNipunn Koorapati via GitGitGadget, Oct 20, 2020

Read the whole thread, see it on lore, or plain text.

$ cat FOOTERMessages come from the public archive at lore.kernel.org/git, fetched every hour. The front page is chosen and written each morning by an AI editor and can be wrong; the threads themselves are the record. About and API. For agents: an MCP server at https://gitlist.dev/mcp, and any thread, story or person page as Markdown by adding .md to its URL (or sending Accept: text/markdown). Details in /llms.txt.