Re: Interesting analysis of linux kernel threading by IBM

From: Alan Cox (alan@lxorguk.ukuu.org.uk)
Date: Fri Jan 21 2000 - 18:18:51 EST


> The amount of time wasted on a bad scheduler is the following:
>
> O(Num of Times schedule is called * Number of running processes)
>
> When I run SPECWeb96 tests here, I see both a large number of running
> process and a huge number of context switches.

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.

Specweb99 which does at least pretend to be a credible benchmark you would
see more running because of your cgis, although in most real world cases your
cgi will be short lived, and if performance critical be a module in your
web server so not more threads.

Alan

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.rutgers.edu
Please read the FAQ at http://www.tux.org/lkml/



This archive was generated by hypermail 2b29 : Sun Jan 23 2000 - 21:00:26 EST