Re: pthread_create() slow for many threads; also time to revisit64b context switch optimization?

From: Arjan van de Ven
Date: Wed Aug 13 2008 - 14:17:06 EST


On Wed, 13 Aug 2008 11:04:29 -0700
Ulrich Drepper <drepper@xxxxxxxxxx> wrote:

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> Linus Torvalds wrote:
> > Ulrich, I don't understand why you worry more about a _potential_
> > (and fairly unlikely) complaint, than about a real one today.
>
> Of course I care. All I try to do is to prevent going from one
> extreme (all focus on P4s) to the other (ignore P4s completely).

(fwiw as far as I know this is only about early 64 bit P4s, not later
generations)
>
> Even ignoring this one case here, I think it's in any case useful for
> userlevel to tell the kernel that an anonymous memory region is needed
> for a stack. This might allow better optimizations and/or security
> implementations.

yeah maybe we should also tell it we expect it to be used downwards.
Oh wait.. MAP_GROWSDOWN ?

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