Date: Mon, 17 Aug 2015 18:01:00 +0300 From: Solar Designer <solar@...nwall.com> To: john-dev@...ts.openwall.com Subject: Re: FMT_OMP_BAD On Mon, Aug 17, 2015 at 10:53:06PM +0800, Kai Zhao wrote: > On my laptop and build with ./configure && make -sj8 > > $ OMP_NUM_THREADS=1 ../john -test -form=wpapsk > Warning: OpenMP is disabled; a non-OpenMP build may be faster > Benchmarking: wpapsk, WPA/WPA2 PSK [PBKDF2-SHA1 256/256 AVX2 8x]... DONE > Raw: 3232 c/s real, 3232 c/s virtual > > $ OMP_NUM_THREADS=10 ../john -test -form=wpapsk > Will run 10 OpenMP threads > Benchmarking: wpapsk, WPA/WPA2 PSK [PBKDF2-SHA1 256/256 AVX2 8x]... > (10xOMP) DONE > Raw: 9346 c/s real, 2038 c/s virtual > > So the wpapsk format should set FAST_FORMATS_OMP and > FMT_OMP_BAD ? No. You shouldn't be setting OMP_NUM_THREADS higher than your logical CPU count for any sort of benchmarking. (You may do so for a stress-test, when trying to trigger a bug.) Also, your laptop's CPU almost certainly does not have 8 physical cores (probably it has 4), and its clock rate likely reduces a lot when you use all 4 cores at once. wpapsk actually scales very well: http://www.openwall.com/lists/john-dev/2015/08/17/21 11560/1308 = 8.84 http://www.openwall.com/lists/john-dev/2015/08/16/23 Perfect for this test is 9.39. 8.84/9.39 = 94% of perfect Alexander
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