Messages in this thread | | | Date | Fri, 21 Jan 2000 20:03:34 -0800 | From | "David S. Miller" <> | Subject | Re: Interesting analysis of linux kernel threading by IBM |
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Date: Fri, 21 Jan 2000 23:18:51 +0000 (GMT) From: Alan Cox <alan@lxorguk.ukuu.org.uk>
> When I run SPECWeb96 tests here, I see both a large number of running > process and a huge number of context switches.
Running 2.2.x I imagine as well, right?
Specweb96 is about as relevant to real world web performance as the colour of car you own. And in this case massively so. Run your test with thttpd. Your run queue length will be _one_. Always one, never more and under load never less. Its an architectural issue in your web server.
Only partly true Alan, only 2.3.x has the "dumb wakeups" issue with TCP accept fixed (2.2.x will cause ~3 wakeups for each new connection when only 1 should be made). That plays a big factor as well, remember the same exact thread about all of this "run queue scalability" bogosity we had nearly a year ago?
So to the original specweb96 tester, divide your context switch number by 3, does it look more sane now? :-)
However Alan is right, web server architecture has a lot to do with bad "benchmark" performance.
Later, David S. Miller davem@redhat.com
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