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Date: Thu, 06 Jan 2005 16:56:15 +0800
From: David Xu <davidxu@freebsd.org>
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To: Petri Helenius <pete@he.iki.fi>
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Subject: Re: higher speed mutexes
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I will have low overhead pthread library available soon, for
simple mutex, it is only an atomic_cmpset_long() plus a function
call (pthread_mutex_lock) overhead.

David Xu

Petri Helenius wrote:

> 
> Hi,
> 
> I have some low-contention mutexes which I'm trying to make perform 
> better and I'm wondering if the current threading library does have some 
> primitives I could use or if I'm better off using atomic_cmpset_* and 
> pthread_yield() if the thread hit's contention (which should be about 
> 1:10000 of the lock/unlock operation).
> 
> Any scheduling caveats from above, except obviously it would spin while 
> waiting for the lock. Most systems I plan on running this on have 
> dual-hypethreading CPU's.
> 
> I remember there were some discussion about dropping i386 compatible 
> support for mutexes and using atomic operations instead. Is there 
> code/compile time options for this on a branch I could check out and 
> give it a spin?
> 
> Pete
> 
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