Re: Excessive context switching on SMP Xeons

Michael Adler wrote:

>On Thu, Oct 07, 2004 at 11:48:41AM -0400, Bill Montgomery wrote:
>
>
>>Alan Stange wrote:
>>
>>The same test on a Dell PowerEdge 1750, Dual Xeon 3.2 GHz, 512k cache,
>>HT on, Linux 2.4.21-20.ELsmp (RHEL 3), 4GB memory, pg 7.4.5:
>>
>>Far less performance that the Dual Opterons with a low number of
>>clients, but the gap narrows as the number of clients goes up. Anyone
>>smarter than me care to explain?
>>
>>
>
>You'll have to wait for someone smarter than you, but I will posit
>this: Did you use a tmpfs filesystem like Alan? You didn't mention
>either way. Alan did that as an attempt remove IO as a variable.
>
>-Mike
>
>

Yes, I should have been more explicit. My goal was to replicate his
experiment as closely as possible in my environment, so I did run my
postgres data directory on a tmpfs.

-Bill Montgomery