Date: Mon, 12 Aug 2013 02:06:31 +0100 From: Rafael Waldo Delgado Doblas <lord.rafa@...il.com> To: john-dev@...ts.openwall.com Subject: Re: Parallella: Litecoin mining Hello, 2013/8/10 Solar Designer <solar@...nwall.com> > This is good news, although the target performance is much higher - I'd > guesstimate 3 kh/s with pure C and 4-5 kh/s with asm code. (We had a > smaller difference between pure C and asm for Katja's bcrypt code - with > best asm speed being about 20% higher than best C speed - but for scrypt > I'd expect a bigger difference due to potential use of IMADD for bit > rotates, and due to Salsa20 containing relatively more ADDs than XORs, > as compared to Blowfish.) > > OK. At a later time, you could even try 4.5, if you make your code > really compact. (Of course, supporting a TMTO factor that is not a > whole number requires slightly different code.) > > I think at this time your priority should be to find out why you're not > getting more than 1.15 kh/s at TMTO factor 6. You could get something > like 2+ kh/s with pure C code with it, with more optimal code (this is > just my gut feeling, though). > > Is the code based off scrypt's -ref or -nosse? Anyhow, even -nosse > performed a lot of unnecessary data copying. This is something I > optimized in escrypt, but only in -sse code. If the problem is indeed > still present in the code you're using, you could compare escrypt's > crypto_scrypt-sse.c against the original in scrypt-1.1.6.tgz and > implement similar optimizations (I mean removing blkxor and blkcpy) for > whatever code revision you have. > > Ok I working on it right now. It looks reasonable to me, except that I did not expect you'd have this > much pre-initialized data (2.5 KB). What is it? > Mmm almost 1.4K is "volatile shared_buf_t M SECTION("shared_dram");" Actually I don’t know why because is not pre-initialized. The rest is weird because even if only have the main function without anything more, I got 1128B of pre-initialized data. > > Why the only information is about text, data and bss sections?. > > What else did you expect to see there? Your scratch space that you use > for scrypt's V? How do you allocate it? > There other sections defined in the linker scrypt: .shared_dram for example. The scratch space is defined as static memory "char scratchpad[SCRATCHBUF_SIZE];" Regards, Rafael. Content of type "text/html" skipped
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