On Sat, Mar 31, 2012 at 12:38:56PM +0100, John Robinson wrote: > On 29/03/2012 22:44, Jim Kukunas wrote: > > Based on xor_speed, the AVX implementation appears to be ~32% faster than the > > SSE implementation on my i7 2600: > > > > generic_sse: 15088.000 MB/sec > > avx: 19936.000 MB/sec > > I just noticed in my logs the other day (recent el5 kernel on a Core 2): > > raid5: automatically using best checksumming function: generic_sse > generic_sse: 7805.000 MB/sec > raid5: using function: generic_sse (7805.000 MB/sec) > raid6: int64x1 2635 MB/s > raid6: int64x2 3208 MB/s > raid6: int64x4 3020 MB/s > raid6: int64x8 2519 MB/s > raid6: sse2x1 5099 MB/s > raid6: sse2x2 5742 MB/s > raid6: sse2x4 8237 MB/s > raid6: using algorithm sse2x4 (8237 MB/s) > > I was just wondering how it's possible to do the RAID6 Q calculation > faster than the RAID5 XOR calculation - or am I reading this log excerpt > wrongly? Out of curiosity, are you running with CONFIG_PREEMPT=y? Thanks. > > It's probably academic, since the machine this is running on only has a > maximum of about 4500 MB/s of memory throughput, and a lot of that would > be consumed sending data to disc in amongst the calculations being done. > > Cheers, > > John. > > -- > To unsubscribe from this list: send the line "unsubscribe linux-raid" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- Jim Kukunas Intel Open Source Technology Center -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
