Date: Sat, 3 Oct 2009 04:59:22 +0200
From: Andi Kleen <andi@firstfloor.org>
To: Tejun Heo <tj@kernel.org>
Cc: Andi Kleen <andi@firstfloor.org>, jeff@garzik.org, mingo@elte.hu,
       linux-kernel@vger.kernel.org, akpm@linux-foundation.org,
       jens.axboe@oracle.com, rusty@rustcorp.com.au, cl@linux-foundation.org,
       dhowells@redhat.com, ar@firstfloor.org
Subject: Re: [PATCH 19/19] workqueue: implement concurrency managed workqueue
Message-ID: <20091003025922.GP1656@one.firstfloor.org>
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> One thing is that for userspace there's already pretty thick layer of
> abstraction in place and having this type of bare metal mechanism
> might not buy much.  In most cases, monitoring system parameters

That can be costly in terms of power/cpu cycles.

> periodically and supplying a bit of extra threads should be able to
> achieve about the same result.  Do you have anything specific on your
> mind?

I was thinking of a special file descriptor that could be polled on.
Register threads to be monitored and get a notification back this
way when they are busy above some threshold. Then a runtime could
start more threads upto the maximum number of cores. This would
be mainly useful with existing work distributing libraries 
like threadbuildingblocks.

-Andi
-- 
ak@linux.intel.com -- Speaking for myself only.
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