Date: Sat, 6 Jun 2015 19:38:18 +0800 From: Lei Zhang <zhanglei.april@...il.com> To: john-dev@...ts.openwall.com Subject: Re: Interleaving of intrinsics > On Jun 6, 2015, at 1:01 AM, magnum <john.magnum@...hmail.com <mailto:john.magnum@...hmail.com>> wrote: > > You should probably do much longer runs (eg --test=15 or more) to get things like cfg_get_section completely out of the way. > >> '__memcpy_sse2_unaligned' might imply some overhead incurred from >> unaligned memcpy, which is irrelevant to this topic though. > > If this is still seen on longer runs, we should look into it. Maybe we should try callgrind with very long test runs (--test=60 or much more) and see if it can sample enough for kcachegrind to show some info within the hash functions. This might even help see relations between the source and the resulting assembler. Same settings as the previous, except for longer run time (--test=20): x1 Function CPU Time __memcpy_sse2_unaligned 1.475s memcpy 0.975s pbkdf2_sha256_sse 0.383s SSESHA256body 0.224s _mm_xor_si128 0.088s [Others] 17.294s x2 Function CPU Time SSESHA256body 3.759s __memcpy_sse2_unaligned 0.735s pbkdf2_sha256_sse 0.280s _mm_xor_si128 0.108s _mm_srli_epi32 0.056s [Others] 15.929s x3 Function CPU Time SSESHA256body 4.155s __memcpy_sse2_unaligned 0.563s pbkdf2_sha256_sse 0.426s _mm_srli_epi32 0.108s _mm_add_epi32 0.076s [Others] 15.929s x4 Function CPU Time SSESHA256body 4.292s __memcpy_sse2_unaligned 0.559s pbkdf2_sha256_sse 0.340s _mm_srli_epi32 0.148s _mm_slli_epi32 0.083s [Others] 16.184s Use of intrinsics is counted as function calls, so their run time is included in the '[Others]' row, rather than in SSESHA256body. Yet '__memcpy_sse2_unaligned' is still there. It's likely used to accelerate memcpy by using SIMD instructions. I thinks it just implies the overhead of memcpys in JtR, which is normal. Lei Content of type "text/html" skipped
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