> -----Original Message----- > From: linux-raid-owner@xxxxxxxxxxxxxxx [mailto:linux-raid- > owner@xxxxxxxxxxxxxxx] On Behalf Of Bill Davidsen > Sent: Wednesday, September 28, 2005 4:05 PM > To: Guy > Cc: 'Holger Kiehl'; 'Mark Hahn'; 'linux-raid'; 'linux-kernel' > Subject: Re: Where is the performance bottleneck? > > Guy wrote: > > >In most of your results, your CPU usage is very high. Once you get to > about > >90% usage, you really can't do much else, unless you can improve the CPU > >usage. > > > That seems one of the problems with software RAID, the calculations are > done in the CPU and not dedicated hardware. As you move to the top end > drive hardware the CPU gets to be a limit. I don't remember off the top > of my head how threaded this code is, and if more CPUs will help. My old 500MHz P3 can xor at 1GB/sec. I don't think the RAID5 logic is the issue! Also, I have not seen hardware that fast! Or even half as fast. But I must admit, I have not seen a hardware RAID5 in a few years. :( 8regs : 918.000 MB/sec 32regs : 469.600 MB/sec pIII_sse : 994.800 MB/sec pII_mmx : 1102.400 MB/sec p5_mmx : 1152.800 MB/sec raid5: using function: pIII_sse (994.800 MB/sec) Humm.. It did not select the fastest? Guy > > I see you are using RAID-1 for your system stuff, did one of the tests > use RAID-0 over all the drives? Mirroring or XOR redundancy help > stability but hurt performance. Was the 270MB/s with RAID-0 or ??? > > -- > bill davidsen <davidsen@xxxxxxx> > CTO TMR Associates, Inc > Doing interesting things with small computers since 1979 > > - > 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 - 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
