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Date:      Mon, 2 Jul 2001 14:11:13 -0500
From:      Alfred Perlstein <bright@sneakerz.org>
To:        Julian Elischer <julian@elischer.org>
Cc:        "Michael C . Wu" <keichii@peorth.iteration.net>, "E.B. Dreger" <eddy+public+spam@noc.everquick.net>, smp@FreeBSD.ORG
Subject:   Re: per cpu runqueues, cpu affinity and cpu binding.
Message-ID:  <20010702141113.Q84523@sneakerz.org>
In-Reply-To: <Pine.BSF.4.21.0107021303460.13213-100000@InterJet.elischer.org>; from julian@elischer.org on Mon, Jul 02, 2001 at 01:19:04PM -0700
References:  <20010702115044.C99436@peorth.iteration.net> <Pine.BSF.4.21.0107021303460.13213-100000@InterJet.elischer.org>

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* Julian Elischer <julian@elischer.org> [010702 13:38] wrote:
> 
> At USENIX we decided to proceed with the KSE work.

yay!

> I have already re-implemented the proc-splitting patches from January and 
> have split the proc structure into parts to support threads. In this case
> teh processor affinity stuff that alfred has done are already in a
> per-thread (per kse) basis. Individual threads may migrate between KSEs
> but if teh program acts to implement KSEs (thread carriers) on multiple
> processors then they will try STAY on particular processors.
> 
> As a side issue I plan on NOT ALLOWING multiple KSEs (thread carriers?)
> from the same thread group in the same process to be on the same
> processor. SO load balancing and processor affinity will not
> apply to the thread-carrying entities (KSEs). Of course the userland
> thread scheduler has the ultimate say as to which processor
> a thread is scheduled on.

Actually, this may cause some performance problems, when you have
a shared address space you can avoid tlb shootdowns when a process's
address space changes, you also share the cache, lastly there's
some rumor about a new CPU archetecture that runs multple threads
on the same CPU at the same time.  Just food for thought.

-- 
-Alfred Perlstein [alfred@freebsd.org]
Ok, who wrote this damn function called '??'?
And why do my programs keep crashing in it?

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