Date: Thu, 29 Aug 2013 02:55:25 +0100 From: Rafael Waldo Delgado Doblas <lord.rafa@...il.com> To: john-dev@...ts.openwall.com Subject: Re: Parallella: Litecoin mining Hello Alexander, 2013/8/29 Solar Designer <solar@...nwall.com> > Does this mean that replacing memcpy() improved the overall speed by as > much as 15% or so? If so, this suggests that the code wastes too much > time copying data, and needs to be revised at higher level (than memcpy() > itself), in addition to optimizing memcpy(). > > Also, I just took a look at your currently committed code - your > memcpy() replacement, at least at source code level, copies data byte by > byte. This is very slow, unless the compiler optimizes this into 32-bit > or 64-bit loads and stores somehow. I doubt that replacing memcpy() > with this implementation of blkcpy() provided any speedup (but I could > be wrong - weird things happen). > > Ideally, your blkcpy() should be a partially unrolled loop with LDRD and > STRD instructions in it, and all of the data needs to be 8 byte aligned. > Maybe is because the memcpy it's stored in the external memory (as the rest of libc), but I can do some test to check if it's a real improvement. > > I'm checking the bug in the host code > > Do you mean the occasional segfault? How are you debugging it, exactly? > (I asked you this question a few days ago, but you did not answer.) > Sorry I didn't see it. Yes I mean the occasional segfault and yes it was produced when a share is find, I think that I fixed it, but I'm testing it right now. > and I will move to asm ASAP > > OK, although there's more we can do at C level as well. > > What portions of code will you be rewriting in asm? Are you starting > with inline asm or with a separate assembly source file? > I was thinking in replace the rotates by IMADD and LSR as you said before,using inline asm. Regards, Rafael. Content of type "text/html" skipped
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