Messages in this thread | | | Date | Wed, 9 Mar 2005 12:04:58 -0800 | From | Andrew Morton <> | Subject | Re: Direct io on block device has performance regression on 2.6.x kernel |
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"Chen, Kenneth W" <kenneth.w.chen@intel.com> wrote: > > Andrew Morton wrote on Tuesday, March 08, 2005 10:28 PM > > But before doing anything else, please bench this on real hardware, > > see if it is worth pursuing. > > Let me answer the questions in reverse order. We started with running > industry standard transaction processing database benchmark on 2.6 kernel, > on real hardware (4P smp, 64 GB memory, 450 disks) running industry > standard db application. What we measured is that with best tuning done > to the system, 2.6 kernel has a huge performance regression relative to > its predecessor 2.4 kernel (a kernel from RHEL3, 2.4.21 based).
That's news to me. I thought we were doing OK with big database stuff. Surely lots of people have been testing such things.
> And yes, it is all worth pursuing, the two patches on raw device recuperate > 1/3 of the total benchmark performance regression.
On a real disk driver? hm, I'm wrong then.
Did you generate a kernel profile?
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