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Re: [PATCH 1/4] fsmonitor: use fsmonitor data in `git diff`

From
Junio C Hamano <gitster@pobox.com>
Date
Oct 19, 2020, 17:23 UTC
Message-ID
<xmqqr1puuo35.fsf@gitster.c.googlers.com>
In-Reply-To
<20201018234344.GC4204@nand.local>
Taylor Blau <me@ttaylorr.com> writes:
Show 8 quoted lines
>> > There is some overhead to invoke the hook and talk to watchman, but
>> > I'd expect that to be dwarfed by not having to issue O(# files)
>> > syscalls.
>>
>> "invoke the hook"---is that a pipe+fork+exec, or something else that
>> is far lighter-weight?
>
> The former; see 'fsmonitor.c:query_fsmonitor()'.

It brings us back to the "overhead of how many lstat(2) takes us closer to the overhead of a single pipe+fork+exec plus reading from the pipe", doesn't it?

Previous: Taylor BlauNext: Taylor Blau
Message 8 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

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