On 27 Aug 2003 at 19:00, Neil Conway wrote: > On Wed, Aug 27, 2003 at 09:02:25PM +0530, Shridhar Daithankar wrote: > > IIRC in a kernel release note recently, it was commented that IO scheduler is > > still being worked on and does not perform as much for random seeks, which > > exaclty what database needs. > > Yeah, I've read that as well. It would be interesting to see how 2.6 > performs with the traditional (non-anticipatory) scheduler -- I believe > you can switch from one I/O scheduler to another via a sysctl.
I will repeat the tests after get that setting. Will google for it.. > > > pgbench -c10 -t100 test1 > > tps = 64.917044 (including connections establishing) > > tps = 65.438067 (excluding connections establishing) > > Interesting that the performance of 2.4.20 for this particular > benchmark is a little less than 3 times faster than 2.6 Yeah but 2.4 drops like anything.. > > 4) noatime enabled Shared buffers 3000 > > > > pgbench -c5 -t100 test > > tps = 90.850600 (including connections establishing) > > tps = 92.053686 (excluding connections establishing) > > > > pgbench -c5 -t1000 test > > tps = 92.209724 (including connections establishing) > > tps = 92.329682 (excluding connections establishing) > > > > pgbench -c10 -t100 test > > tps = 79.264231 (including connections establishing) > > tps = 80.145448 (excluding connections establishing) > > I'm a little skeptical of the consistency of these numbers > (several people have observed in the past that it's difficult > to get pgbench to produce reliable results) -- how is it > possible that using noatime can possibly *reduce* performance > by 50%, in the case of the first and third benchmarks? I know. I am puzzled too. Probably I didn't put noatime properly in /etc/fstab. Unfortunately I have only one linux partition. So I prefer to boot rather than remounting root. I will redo the bechmarks and post the results.. Bye Shridhar -- Law of Communications: The inevitable result of improved and enlarged communications between different levels in a hierarchy is a vastly increased area of misunderstanding. ---------------------------(end of broadcast)--------------------------- TIP 1: subscribe and unsubscribe commands go to [EMAIL PROTECTED]
