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Date: Tue, 03 Jan 2006 13:18:26 -0700
From: Scott Long <scottl@samsco.org>
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To: Daniel Eischen <deischen@freebsd.org>
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Cc: freebsd-hackers@freebsd.org, prime <guomingyan@gmail.com>
Subject: Re: An idea of remove MUTEX_WAKE_ALL
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Daniel Eischen wrote:

> On Tue, 3 Jan 2006, Scott Long wrote:
> 
> 
>>>for a bit if the current lock owner is running on another CPU?
>>>Do we currently do that?
>>>
>>>(*) No, I am not referring to spin mutexes.
>>>
>>
>>Adaptive mutexes are enabled by default and have been for at least a
>>year.
> 
> 
> Ahh, then that's what they (Adaptive) do.
> 

Well, it's a bit different from Solaris, I believe.  They do not sleep
after a certain number of contested spins, and instead just continue to
spin.  As we reduce the coverage of large contested locks (like Giant)
this becomes much less of performance problem, though.

Scott