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Re: [PATCH 0/7] block-sha1: improved SHA1 hashing

From
ASArtur Skawina <art.08.09@gmail.com>
Date
Aug 6, 2009, 21:39 UTC
Message-ID
<4A7B4D84.80906@gmail.com>
In-Reply-To
<alpine.LFD.2.01.0908061329320.3390@localhost.localdomain>
Linus Torvalds wrote:
Show 6 quoted lines
> 
> with it, so it is faster for me. So your slowdown seems to be yet another 
> P4 thing. Dang crazy micro-architecture.
> 
> Of course, it might be a compiler version difference too. I'm using 
> gcc-4.4.0.
gcc version 4.4.1 20090603 (prerelease)
Show 14 quoted lines
> Oh, I did make a small change, but I doubt it matters. Instead of doing
> 
> 	TEMP += E + SHA_ROL(A,5) + (fn) + (constant); \
> 	B = SHA_ROR(B, 2); E = TEMP; } while (0)
> 
> I now do
> 
> 	E += TEMP + SHA_ROL(A,5) + (fn) + (constant); \
> 	B = SHA_ROR(B, 2); } while (0)
> 
> which is a bit more logical (the old TEMP usage was just due to a fairly 
> mindless conversion). That _might_ have lower register pressure if the 
> compiler is silly enough to not notice that it can do it. Maybe that 
> matters.

before: linus 0.6622 92.17 after: linus 0.6631 92.05 after: linus 0.6601 92.46 after: linus 0.6624 92.14

IOW, no difference, just noise.
Previous: Linus TorvaldsNext: Artur Skawina
Message 17 of 37 in “block-sha1: improved SHA1 hashing”
  1. 0/7 block-sha1: improved SHA1 hashingLinus Torvalds, Aug 6, 2009
  2. 1/7 block-sha1: add new optimized C 'block-sha1' routinesLinus Torvalds, Aug 6, 2009
  3. 2/7 block-sha1: try to use rol/ror appropriatelyLinus Torvalds, Aug 6, 2009
  4. 3/7 block-sha1: make the 'ntohl()' part of the first SHA1 loopLinus Torvalds, Aug 6, 2009
  5. 4/7 block-sha1: re-use the temporary array as we calculate the SHA1Linus Torvalds, Aug 6, 2009
  6. 5/7 block-sha1: macroize the rounds a bit furtherLinus Torvalds, Aug 6, 2009
  7. 6/7 block-sha1: Use '(B&C)+(D&(B^C))' instead of '(B&C)|(D&(B|C))' in round 3Linus Torvalds, Aug 6, 2009
  8. 7/7 block-sha1: get rid of redundant 'lenW' contextLinus Torvalds, Aug 6, 2009
  9. Bert WesargAug 6, 2009
  10. Artur SkawinaAug 6, 2009
  11. Linus TorvaldsAug 6, 2009
  12. Artur SkawinaAug 6, 2009
  13. Linus TorvaldsAug 6, 2009
  14. Artur SkawinaAug 6, 2009
  15. Linus TorvaldsAug 6, 2009
  16. Linus TorvaldsAug 6, 2009
  17. Artur SkawinaAug 6, 2009
  18. Artur SkawinaAug 6, 2009
  19. Linus TorvaldsAug 6, 2009
  20. Linus TorvaldsAug 6, 2009
  21. Artur SkawinaAug 6, 2009
  22. Linus TorvaldsAug 6, 2009
  23. Artur SkawinaAug 6, 2009
  24. Linus TorvaldsAug 6, 2009
  25. Linus TorvaldsAug 6, 2009
  26. Linus TorvaldsAug 7, 2009
  27. Artur SkawinaAug 7, 2009
  28. Linus TorvaldsAug 7, 2009
  29. Artur SkawinaAug 7, 2009
  30. Linus TorvaldsAug 7, 2009
  31. Artur SkawinaAug 7, 2009
  32. Linus TorvaldsAug 8, 2009
  33. Artur SkawinaAug 8, 2009
  34. Linus TorvaldsAug 8, 2009
  35. Artur SkawinaAug 8, 2009
  36. Artur SkawinaAug 8, 2009
  37. Artur SkawinaAug 8, 2009

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