* 2.4.17 raid5 checksumming function selection wierdness @ 2002-01-11 12:12 Anders Vedmar 2002-01-11 12:17 ` David S. Miller 2002-01-11 12:26 ` Dave Jones 0 siblings, 2 replies; 3+ messages in thread From: Anders Vedmar @ 2002-01-11 12:12 UTC (permalink / raw) To: linux-kernel The raid5 code in 2.4.17 seems to select the slowest available checksumming function. Part of dmesg output follows: [...] raid5: measuring checksumming speed 8regs : 2148.000 MB/sec 32regs : 1900.400 MB/sec pIII_sse : 1272.000 MB/sec pII_mmx : 3291.200 MB/sec p5_mmx : 4212.400 MB/sec raid5: using function: pIII_sse (1272.000 MB/sec) [...] The machine is an Athlon XP 1400MHz on an MSI K7T266Pro2 board with 512 Mb of PC2100 DDR. -- /A ^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: 2.4.17 raid5 checksumming function selection wierdness 2002-01-11 12:12 2.4.17 raid5 checksumming function selection wierdness Anders Vedmar @ 2002-01-11 12:17 ` David S. Miller 2002-01-11 12:26 ` Dave Jones 1 sibling, 0 replies; 3+ messages in thread From: David S. Miller @ 2002-01-11 12:17 UTC (permalink / raw) To: anders.vedmar; +Cc: linux-kernel From: Anders Vedmar <anders.vedmar@interactiveinstitute.se> Date: Fri, 11 Jan 2002 13:12:53 +0100 The raid5 code in 2.4.17 seems to select the slowest available checksumming function. It does so because: 1) It performs better for the cache miss case and 2) it is more cache friendly ^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: 2.4.17 raid5 checksumming function selection wierdness 2002-01-11 12:12 2.4.17 raid5 checksumming function selection wierdness Anders Vedmar 2002-01-11 12:17 ` David S. Miller @ 2002-01-11 12:26 ` Dave Jones 1 sibling, 0 replies; 3+ messages in thread From: Dave Jones @ 2002-01-11 12:26 UTC (permalink / raw) To: Anders Vedmar; +Cc: linux-kernel On Fri, 11 Jan 2002, Anders Vedmar wrote: > The raid5 code in 2.4.17 seems to select the slowest available > checksumming function. > 8regs : 2148.000 MB/sec > pIII_sse : 1272.000 MB/sec > raid5: using function: pIII_sse (1272.000 MB/sec) SSE is favoured due to it avoiding trashing the cache contents. -- | Dave Jones. http://www.codemonkey.org.uk | SuSE Labs ^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2002-01-11 12:27 UTC | newest] Thread overview: 3+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2002-01-11 12:12 2.4.17 raid5 checksumming function selection wierdness Anders Vedmar 2002-01-11 12:17 ` David S. Miller 2002-01-11 12:26 ` Dave Jones
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