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Re: [PATCH 3/3] Avoid doing extra 'lstat()'s for d_type if we have an up-to-date cache entry

From
Dmitry Potapov <dpotapov@gmail.com>
Date
Jul 9, 2009, 13:50 UTC
Message-ID
<20090709135010.GA19425@dpotapov.dyndns.org>
In-Reply-To
<alpine.LFD.2.01.0907081942380.3352@localhost.localdomain>
On Wed, Jul 08, 2009 at 07:43:50PM -0700, Linus Torvalds wrote:
Show 5 quoted lines
> 
> On filesystems without d_type, we can look at the cache entry first.
> Doing an lstat() can be expensive.
> 
> Reported by Dmitry Potapov for Cygwin.

I have tested it on Cygwin. The number of 'stat' for files is now 1, so it works fine :)

I still have the same large number of 'stat' calls for directories, but I suspect that due to that due to some Cygwin specific. I will investigate that issue later when I have more time.

Because the repositoty on which I did testing has too many directories (one directory per each 3.5 files) the effect was not as prominent as it would be otherwise. Yet, it is 24.9% decrease of the number of 'stat' or 14.8% descreased of the total number of syscalls. And my measurement shows 14% descrease of run-time. So, it appears that on Windows the run time almost directly proportional of the total number of syscalls...

BTW, I believe that this patch should help MinGW too, because AFAIK MinGW does not have d_type either.

Thanks, Dmitry

Previous: Dmitry Potapov
Message 39 of 39 in “Too many 'stat' calls by git-status on Windows”
  1. Dmitry PotapovJul 7, 2009
  2. Ramsay JonesJul 8, 2009
  3. Linus TorvaldsJul 9, 2009
  4. Linus TorvaldsJul 9, 2009
  5. 1/3 Add 'fill_directory()' helper function for directory traversalLinus Torvalds, Jul 9, 2009
  6. 2/3 Simplify read_directory[_recursive]() argumentsLinus Torvalds, Jul 9, 2009
  7. 3/3 Avoid doing extra 'lstat()'s for d_type if we have an up-to-date cache entryLinus Torvalds, Jul 9, 2009
  8. Junio C HamanoJul 9, 2009
  9. Linus TorvaldsJul 9, 2009
  10. Junio C HamanoJul 9, 2009
  11. Linus TorvaldsJul 9, 2009
  12. Junio C HamanoJul 9, 2009
  13. Linus TorvaldsJul 9, 2009
  14. Linus TorvaldsJul 9, 2009
  15. Junio C HamanoJul 9, 2009
  16. Linus TorvaldsJul 9, 2009
  17. 4/3 Avoid using 'lstat()' to figure out directoriesLinus Torvalds, Jul 9, 2009
  18. 5/3 Prepare symlink caching for thread-safetyLinus Torvalds, Jul 9, 2009
  19. 6/3 Export thread-safe version of 'has_symlink_leading_path()'Linus Torvalds, Jul 9, 2009
  20. 7/3 Make index preloading check the whole path to the fileLinus Torvalds, Jul 9, 2009
  21. Linus TorvaldsJul 9, 2009
  22. Junio C HamanoJul 10, 2009
  23. Linus TorvaldsJul 10, 2009
  24. Linus TorvaldsJul 10, 2009
  25. Junio C HamanoJul 11, 2009
  26. Linus TorvaldsJul 11, 2009
  27. Kjetil BarvikJul 12, 2009
  28. Junio C HamanoJul 12, 2009
  29. Paolo BonziniJul 9, 2009
  30. Linus TorvaldsJul 9, 2009
  31. Linus TorvaldsJul 9, 2009
  32. Linus TorvaldsJul 10, 2009
  33. Junio C HamanoJul 9, 2009
  34. Dmitry PotapovJul 9, 2009
  35. Eric BlakeJul 9, 2009
  36. Dmitry PotapovJul 9, 2009
  37. Dmitry PotapovJul 10, 2009
  38. Dmitry PotapovJul 9, 2009
  39. Dmitry PotapovJul 9, 2009

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