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From "William A. Rowe Jr." <wr...@rowe-clan.net>
Subject Re: mod_authn_file + low ThreadStackSize = oops
Date Wed, 27 Oct 2010 19:03:27 GMT
On 10/27/2010 12:53 PM, Eric Covener wrote:
>> I'd set my ThreadStackSize really low, to 64 KB, and while that usually lets you
run without trouble
> 
> I was just about to document that _lowering_ the stack size with
> ThreadStackSize is unreliable since the underlying call used only sets
> a _minimum_ stack size, not an actual one.

It's not a pre-allocation, AIUI.  It is the ceiling to which the stack may
grow, at which point it's probably bumping up against the next thread's
own stack.  Especially with 32-bit execution, this becomes critical for
worker/event etc, because 1024mb reservations would allow only 1024 stacks
(or threads) to sit within a typical 1GB window of potential stack allocations.

Dropping it to 64kb (which probably would not work!) provides 16k stacks.

> Did you have any extenuating circumstances (old linux, alternate
> thread library, ulimit -s already set below 128?)

Always a good question.

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