Messages in this thread | | | Date | Tue, 20 May 2008 18:39:12 +0200 | From | Benoit Boissinot <> | Subject | Re: [PATCH 1/2] bitreversal program |
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On Tue, May 20, 2008 at 05:57:37PM +0200, Soumyadip Das Mahapatra wrote: > On Tue, 20 May 2008, Benoit Boissinot wrote: >> On Tue, May 20, 2008 at 5:25 PM, Soumyadip Das Mahapatra >> <kernelhacker@visualserver.org> wrote: >>> I know that my bitrev8() takes more instructions than that >>> of yours. But we have to think about faster access of cpu cache over that >>> of memory cache(which your bit_rev_table uses). >> >> I didn't review your patch, sorry. >> But I'm pretty sure that your patch won't be considered unless you >> provide benchmarks >> with numbers for different CPU/architecture. >> Ideally you should provide a script to test the correctness and the >> performance of your >> change that anyone could run on his computer. > > Thanks Benoit for giving me such a precious advice. But sorry, I dont > have any benchmarking system in my hand(how can i have? i am just a > student, not a professional). > So if you do me a favour and kindly do it for me, please :-)
A quick benchmarking (that you should have done at least one your computer gives for 100000000 iterations): old: real 0m1.631s user 0m1.628s sys 0m0.004s
new: real 0m5.553s user 0m5.540s sys 0m0.004s
So I guess there's no need to discuss this further.
regards,
Benoit
-- :wq
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