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From Colm MacCarthaigh <>
Subject Re: [PATCH] raise MAX_SERVER_LIMIT
Date Thu, 15 Jan 2004 16:04:38 GMT
On Thu, Jan 15, 2004 at 10:49:43AM -0500, wrote:
> >-#define MAX_SERVER_LIMIT 20000
> >+#define MAX_SERVER_LIMIT 100000
> dang!
> Committed a limit of 200000.
> A couple of observations:
> * I don't think you could do this with an early 2.4 kernel on i386 because 
> of eating up kernel memory with LDTs, assuming APR thinks it can support 
> threads. Not sure about current kernels from popular distros.

I'm running 2.6.1-mm2 now, and things are much much better, we got away
with it - just about with 2.6.1 vanilla, but -mm2 has improved the
stability a lot. Peaked at just over 18,000 with 2.6.1-mm2 so far and
it was a lot more bearable.

We were having major stability problems with 2.4, and as soon as we
went to 2.6 we found out why - we were getting a lot more client
requests than we thought, but they were queuing. We hit 20,000 within
2 days of going to 2.6.1-rc2. 

There were other changes co-incidental to that, like going to 12Gb
of RAM, which certainly helped, so it's hard to narrow it down too

> * Should I assume you tried worker but it uses too much CPU?  If so, is it 
> a small percentage more or really really bad?

I don't use worker because it still dumps an un-backtracable corefile
within about 5 minutes for me. I still have no idea why, though plenty
of corefiles. I havn't tried a serious analysis yet, becasue I've been
moving house, but I hope to get to it soon. Moving to worker would be
a good thing :)

If I get time, I'll compile the forensic logging module and see if
I can find if it has a  request-specific trigger I can replicate for
testing. I have worker running for months on end on the exact same
platform with much lower yield rates, so I suspect the problem is
only being triggered by the sheer volume of requests.

Colm MacCárthaigh                        Public Key:

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