Date: Wed, 16 Sep 2015 04:28:42 +0300 From: Solar Designer <solar@...nwall.com> To: john-dev@...ts.openwall.com Subject: Re: Judy array On Wed, Sep 16, 2015 at 02:29:17AM +0300, Solar Designer wrote: > real 0m57.785s > user 4m21.243s > sys 0m15.629s > > Oops. Almost same speed without actual prefetching. So maybe the > re-arranged code is somehow faster in this case, even when I don't > prefetch. Or maybe the CPU does speculative execution and thus > prefetches anyway, using those pointers that the following few loop > iterations would use (especially as the compiler unrolls the loop). Implemented better prefetching, patch attached. New speed: real 0m56.260s user 4m9.024s sys 0m16.240s Best of several runs: real 0m55.987s user 4m7.024s sys 0m16.082s I think this should be committed, and I might get it into core tree later. Even though we'll probably replace this with Fred's code soon. I guess what I am doing is providing another baseline for comparison. Alexander View attachment "john-huge-prefetch.diff" of type "text/plain" (4518 bytes)
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