On Thu, 20 Nov 2003, Mikael Johansson wrote: > > Hello All! > > Has anyone else experienced a drastic drop in read performance on software > RAID-0 with post 2.4.20 kernels? We have a few Athlon XP's here at our > lab with double IDE disks on different channels set up as RAID-0. Some > bonnie++ benchmark results with various kernels, on the same machine > (Athlon XP 2400+, 2 GHz, 1.5 GB RAM, VIA chipset, 2*Maxtor 120 GB > 6Y060L0): > write read > 2.4.20-ac1: 88,000 135,000 K/sec > 2.4.21-pre7: 93,000 75,000 > 2.4.22-ac4: 94,000 82,000 > > So the write speed has gone up a bit, but the read speed performance has > plunged. Any ideas on what happened between 2.4.20 and 2.4.21 and what to > do about it? I'm eagerly awaiting suggestions, good read speed is quite > critical for many of our calculations :-) I will of course provide more > details if necessary. There have been no significant changes in the RAID driver in 2.4.21, so I suspect the cause for the slowdowns might the changes to the IO scheduler (ll_rw_blk.c) or VM changes. Isolating the -pre which the slowdown starts helps a lot. - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
