Messages in this thread | | | Date | Thu, 19 Jan 2006 21:18:19 +0800 | From | Max Waterman <> | Subject | Re: io performance... |
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Unfortunately, they don't want me to spend time doing this sort of thing, so I'm out of luck.
They're going to stick with 2.6.8-smp, which seems to give the best performance (which rules out your second case below, I suppose).
:|
Max.
Adrian Bunk wrote: > On Mon, Jan 16, 2006 at 03:35:31PM +0800, Max Waterman wrote: >> Hi, >> >> I've been referred to this list from the linux-raid list. >> >> I've been playing with a RAID system, trying to obtain best bandwidth >> from it. >> >> I've noticed that I consistently get better (read) numbers from kernel 2.6.8 >> than from later kernels. >> >> For example, I get 135MB/s on 2.6.8, but I typically get ~90MB/s on later >> kernels. >> >> I'm using this : >> >> <http://www.sharcnet.ca/~hahn/iorate.c> >> >> to measure the iorate. I'm using the debian distribution. The h/w is a >> MegaRAID >> 320-2. The array I'm measuring is a RAID0 of 4 Fujitsu Max3073NC 15Krpm >> drives. >> >> The later kernels I've been using are : >> >> 2.6.12-1-686-smp >> 2.6.14-2-686-smp >> 2.6.15-1-686-smp >> >> The kernel which gives us the best results is : >> >> 2.6.8-2-386 >> >> (note that it's not an smp kernel) >> >> I'm testing on an otherwise idle system. >> >> Any ideas to why this might be? Any other advice/help? > > You should try to narrow the problem a bit down. > > Possible causes are: > - kernel regression between 2.6.8 and 2.6.12 > - SMP <-> !SMP support > - patches and/or configuration changes in the Debian kernels > > You should try self-compiled unmodified 2.6.8 and 2.6.12 ftp.kernel.org > kernels with the same .config (modulo differences by "make oldconfig"). > > After this test, you know whether you are in the first case. > If yes, you could do a bisect search for finding the point where the > regression started. > >> Thanks! >> >> Max. > > cu > Adrian >
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