Messages in this thread | | | Date | Tue, 29 Jul 1997 09:17:36 +0200 (MET DST) | From | Ingo Molnar <> | Subject | Re: Interesting pentium-memcpy results |
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On Mon, 28 Jul 1997, Benjamin Saller Bender wrote:
> Chris Evans <mailto:chris@ferret.lmh.ox.ac.uk> writes: > >I just compared 2.1.46 vs. 2.1.46+pentium memcpy patch, and interestingly > >enough found that the UNIX byte benchmarks tended to _drop_ a fair bit ,
> I haven't done the research to verify how well this will work under > Linux, but for large a memcpy on the P5 we may wanna consider using the FP > unit using double precision read and writes. I have sample code if anyone is > interested.
sigh, this FPU trick is exactly what the 'pentium-memcpy' patch does:
+ "fildq 0x0(%2)\n\t" + "fildq 0x20(%2)\n\t" + "fildq 0x40(%2)\n\t" + "fildq 0x60(%2)\n\t" + "fildq 0x80(%2)\n\t" + "fildq 0xa0(%2)\n\t" + "fildq 0xc0(%2)\n\t" + "fildq 0xe0(%2)\n\t" + "fxch\n\t" + "fistpq 0xc0(%1)\n\t" + "fistpq 0xe0(%1)\n\t" + "fistpq 0xa0(%1)\n\t" + "fistpq 0x80(%1)\n\t" + "fistpq 0x60(%1)\n\t" + "fistpq 0x40(%1)\n\t" + "fistpq 0x20(%1)\n\t" + "fistpq 0x0(%1)\n\t" + + "addl $8, %2\n\t" + "addl $8, %1\n\t"
-- mingo
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