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Re: [PATCH] Avoid running lstat(2) on the same cache entry.

From
Linus Torvalds <torvalds@linux-foundation.org>
Date
Jan 20, 2008, 22:09 UTC
Message-ID
<alpine.LFD.1.00.0801201358280.2957@woody.linux-foundation.org>
In-Reply-To
<65FCA357-7F7E-4FE0-A423-2528A43B915D@zib.de>
On Sun, 20 Jan 2008, Steffen Prohaska wrote:
Show 7 quoted lines
> > 
> > fnmatch? It's certainly visible on Linux, I wonder if the Windows/OSX
> > version is more expensive due to trying to be case-insensitive or
> > something?
> 
> So roughly 50% of the running time is spent in getdirentries
> and fnmatch on the MacBook Pro I used to run these tests.

Ok. That seems to explain it (I have some trouble reading/comparing your profiles against mine, but yeah, fnmatch and getdirentries seem to be excessive from that "invert call tree" thing.

On Linux, the fnmatch and readdir overhead is way down in the noise both before and after the lstat removal. So removing the lstat's - which were fairly cheap, but there were _lots_ of them, made more of a relative difference on Linux.

I don't know what can be done about that on OS X. We really can't avoid reading the directory tree and matching it against ignore files. That's very integral for the status generation of "git commit", after all.

Maybe there are better fnmatch libraries for OS X? But getdirentries() was the bigger cost, and I don't see any alternative for that.

			Linus
Previous: Steffen ProhaskaNext: Johannes Schindelin
Message 25 of 26 in “Updated in-memory index cleanup”
  1. Linus TorvaldsJan 19, 2008
  2. index: be careful when handling long namesJunio C Hamano, Jan 19, 2008
  3. Avoid running lstat(2) on the same cache entry.Junio C Hamano, Jan 19, 2008
  4. Linus TorvaldsJan 19, 2008
  5. Linus TorvaldsJan 19, 2008
  6. Linus TorvaldsJan 20, 2008
  7. Linus TorvaldsJan 20, 2008
  8. Johannes SchindelinJan 20, 2008
  9. Linus TorvaldsJan 20, 2008
  10. Steffen ProhaskaJan 20, 2008
  11. Johannes SchindelinJan 20, 2008
  12. Junio C HamanoJan 21, 2008
  13. Steffen ProhaskaJan 20, 2008
  14. Johannes SchindelinJan 20, 2008
  15. Also use unpack_trees() in do_diff_cache()Johannes Schindelin, Jan 20, 2008
  16. Linus TorvaldsJan 20, 2008
  17. Linus TorvaldsJan 20, 2008
  18. Johannes SchindelinJan 20, 2008
  19. Linus TorvaldsJan 20, 2008
  20. Johannes SchindelinJan 21, 2008
  21. Try to resurrect the handling for 'diff-index -m'Johannes Schindelin, Jan 20, 2008
  22. Linus TorvaldsJan 20, 2008
  23. Brian DowningJan 20, 2008
  24. Steffen ProhaskaJan 20, 2008
  25. Linus TorvaldsJan 20, 2008
  26. Johannes SchindelinJan 20, 2008

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