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Re: [PATCH 5/5] tree-walk: match_entry microoptimization

From
Dan McGee <dpmcgee@gmail.com>
Date
Apr 2, 2011, 17:54 UTC
Message-ID
<BANLkTinMoSBhG2d=JDhR5homsgn=_HB87w@mail.gmail.com>
In-Reply-To
<BANLkTikZ=eH-Jdd-kdvw4JKPbqCr7kviZg@mail.gmail.com>
On Sat, Apr 2, 2011 at 4:06 AM, Nguyen Thai Ngoc Duy <pclouds@gmail.com> wrote:
Show 8 quoted lines
> On Thu, Mar 31, 2011 at 8:38 AM, Dan McGee <dpmcgee@gmail.com> wrote:
>> Before calling strncmp(), see if we can get away with checking only the
>> first character of the passed path components instead.
>>
>> Signed-off-by: Dan McGee <dpmcgee@gmail.com>
>
> I wonder if inlining strcmp() would be better (at least cleaner code).
> It seems like you try to avoid the function call cost here.

100% agree with you, but I have no idea how to do that. Realize also you can use memcmp() here; I tried that and got no noticeable gain (likely due to how short these strings are). However, it is what we use in most other functions in this file. I assume the compiler would inline versions with a static length, but if you have suggestions as to how to inline a non-trivial version here I'm all ears.

-Dan
Previous: Nguyen Thai Ngoc DuyNext: Nguyen Thai Ngoc Duy
Message 21 of 30 in “diff_tree_sha1: skip diff_tree if old == new”
  1. 1/5 diff_tree_sha1: skip diff_tree if old == newDan McGee, Mar 31, 2011
  2. 2/5 tree-walk: drop unused parameter from match_dir_prefixDan McGee, Mar 31, 2011
  3. Dan McGeeAug 30, 2011
  4. 3/5 tree-walk: micro-optimization in tree_entry_interestingDan McGee, Mar 31, 2011
  5. Nguyen Thai Ngoc DuyApr 3, 2011
  6. Junio C HamanoApr 3, 2011
  7. Dan McGeeApr 5, 2011
  8. tree_entry_interesting: inline strncmp()Nguyễn Thái Ngọc Duy, Apr 4, 2011
  9. 4/5 tree-walk: unroll get_mode since loop boundaries are well-knownDan McGee, Mar 31, 2011
  10. Nguyen Thai Ngoc DuyApr 2, 2011
  11. Dan McGeeApr 2, 2011
  12. Nguyen Thai Ngoc DuyApr 3, 2011
  13. Erik Faye-LundApr 4, 2011
  14. Andreas EricssonApr 4, 2011
  15. Junio C HamanoApr 4, 2011
  16. Dan McGeeApr 5, 2011
  17. Antriksh PanyApr 5, 2011
  18. Dan McGeeApr 6, 2011
  19. 5/5 tree-walk: match_entry microoptimizationDan McGee, Mar 31, 2011
  20. Nguyen Thai Ngoc DuyApr 2, 2011
  21. Dan McGeeApr 2, 2011
  22. Nguyen Thai Ngoc DuyMar 31, 2011
  23. Dan McGeeMar 31, 2011
  24. Junio C HamanoApr 1, 2011
  25. Nguyen Thai Ngoc DuyMay 3, 2011
  26. Fwd: [PATCH 1/5] diff_tree_sha1: skip diff_tree if old == newDan McGee, Apr 2, 2011
  27. Dan McGeeAug 30, 2011
  28. Junio C HamanoAug 30, 2011
  29. 1/2 tree-walk: drop unused parameter from match_dir_prefixDan McGee, Sep 9, 2011
  30. 2/2 tree-walk: micro-optimization in tree_entry_interestingDan McGee, Sep 9, 2011

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