j"1LAnZuoQdcKCkpDBKQMCgziGMoPC4VQUckMm<div class="post"><div class="quoteheader"><a href="https://bitcointalk.org/index.php?topic=820.msg9617#msg9617">Quote from: tcatm on August 16, 2010, 12:43:39 AM</a></div><div class="quote">I propose to compile sha256.cpp with -O3 -march=amdfamk10 (will work on 32bit and 64bit) as only CPUs supporting this instruction set (AMD Phenom, Intel i5 and newer) benefit from -4way and it'll improve performance by ~9%.<br/></div>GCC 4.3.3 doesn't support -march=amdfamk10. I get:<br/>sha256.cpp:1: error: bad value (amdfamk10) for -march= switch<br/><br/><br/><div class="quoteheader"><a href="https://bitcointalk.org/index.php?topic=820.msg9630#msg9630">Quote from: NewLibertyStandard on August 16, 2010, 01:49:01 AM</a></div><div class="quote">With 4way, I get significantly better performance when I have all my virtual cores enabled. I think I get about the same amount of hashes when hyper threading is turned off with or without 4way.<br/></div>Hey, you may be onto something!<br/><br/>hyperthreading didn't help before because all the work was in the arithmetic and logic units, which the hyperthreads share.<br/><br/>tcatm's SSE2 code must be a mix of normal x86 instructions and SSE2 instructions, so while one is doing x86 code, the other can do SSE2.<br/><br/>How much of an improvement do you get with hyperthreading?<br/><br/>Some numbers? What CPU is that?<br/></div> text/html
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