On Fri, Apr 02, 2010 at 10:55:53AM -0700, Learner Study wrote: > Hi Keld: > > Thanks for your email... > > 1. Can you pls point me to this benchmark (which shows 500MB/s)? I > would like to know which CPU, HDDs and kernel version used to achieve > this... http://home.comcast.net/~jpiszcz/20080329-raid/ 496843 KB/s for sequential input with 10 raptor drives There probably is an email in the archives with more info on the test. > 2. Secondly, I would like to understand how raid stack (md driver) > scales as we add more cores...if single core gives ~500MB/s, can two > core give ~1000MB/s? can four cores give ~2000MB/s? etc.... No, the performance is normally limited by the number of drives. I would not wsay that more cores woould do a little but it would be in the order of 1-2 % I think. This is also dependent on wheteher the code actually runs threaded. I doubt it.... best regard keld > > Thanks for your time. > > On Fri, Apr 2, 2010 at 4:05 AM, Keld Simonsen <keld@xxxxxxxxxx> wrote: > > On Thu, Apr 01, 2010 at 08:07:25PM -0700, Learner Study wrote: > >> Hi Keld: > >> > >> Do we have raid5/6 numbers for linux on any multi-core CPU? Most of > >> the benchmarks I have seen on wiki show raid5 perf to be ~150MB/s with > >> single core CPUs. How does that scale with multiple cores? Something > >> like intel's jasper forest??? > > > > I have not checked if the benchmarks were on multi core machines. > > It should not matter much if there were more than one CPU, but > > of cause it helps a little. bonnie++ test reports cpu usage, and this > > is not insignificant, say in the 20 -60 % range for some tests, > > but nowhere near a bottleneck. There was one with a raid5 performance > > seq read of about 500 MB/s with 36 % cpu utilization, so it is > > definitely possible to come beyound 150 MB/s. The speed is largely > > dependent on number of disk drives you employ. > > > > > >> If available, can u pls point me to numbers with multi-core CPU? > > > > I dont have such benchmarks AFAIK. But new benchmarks are always welcome, > > so please feel free to submit your findings. > > > > Best regards > > keld > > > >> Thanks! > >> > >> On Wed, Mar 31, 2010 at 1:15 PM, Keld Simonsen <keld@xxxxxxxxxx> wrote: > >> > On Wed, Mar 31, 2010 at 12:42:57PM -0700, Learner Study wrote: > >> >> Hi Linux Raid Experts: > >> >> > >> >> I was looking at following wiki on raid perf on linux: > >> >> > >> >> https://raid.wiki.kernel.org/index.php/Performance > >> >> > >> >> and notice that the performance numbers are with 2.6.12 kernel. > >> >> > >> >> Do we perf numbers for: > >> >> - latest kernel (something like 2.6.27 / 2.6.31) > >> >> - raid 5 and 6 > >> >> > >> >> Can someone please point me to appropriate link? > >> > > >> > The link mentioned above has a number of other performance reports, for other levels of the kernel. > >> > Anyway you should be able to get comparable results for newer kernels, the kernel has not become > >> > slower since 2.6.12 on RAID. > >> > > >> > best regards > >> > Keld > >> > > >> -- > >> 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 -- 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
