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Re: gcc: poor log() performance on Intel x86_64


Torsten Rohlfing writes:
 > Andrew Haley wrote:
 > 
 > > > When I run the two binaries on the exact same box and time them, I get 
 > > > the following outputs:
 > > > 
 > > > time ./testlog64
 > > > 13.264u 0.000s 0:13.26 100.0%   0+0k 0+0io 0pf+0w
 > > > 
 > > > time ./testlog32
 > > > 6.960u 0.004s 0:06.96 100.0%    0+0k 0+0io 0pf+0w
 > >
 > >You have weird hardware.
 > >
 > >[aph@zorro ~]$ time ./testlog64
 > >
 > >real    0m7.330s
 > >user    0m7.328s
 > >sys     0m0.004s
 > >[aph@zorro ~]$ time ./testlog32
 > >
 > >real    0m7.538s
 > >user    0m7.528s
 > >sys     0m0.000s
 > 
 > So it's not a big brand box, but I didn't think of it as totally obscure 
 > either.

Mm yes, but the fact that I can't duplicate your problem suggests that
it might be localized to a particular CPU design of a perticular
library build.  It's hard to be sure, but it's not a generic gcc
problem.

Andrew.


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