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Date:      Thu, 21 Oct 2004 09:56:43 -0400
From:      Lucas Holt <luke@foolishgames.com>
To:        Jason Stone <freebsd-performance@dfmm.org>
Cc:        freebsd-performance@freebsd.org
Subject:   Re: decreasing interrupt CPU load
Message-ID:  <0A85B89D-2369-11D9-BD7C-000A95EFF4CA@foolishgames.com>
In-Reply-To: <20041020133406.V79820@walter>
References:  <20041020133406.V79820@walter>

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On Oct 20, 2004, at 4:34 PM, Jason Stone wrote:

> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
>
>
> I read somewhere that there wasn't a specific reason for not allowing
> device polling and smp to be used at the same time, and that it was 
> fairly
> safe to remove the #ifdef SMP/#error block in sys/kern/kern_poll.c and
> compile in both smp and device polling.
>
> I haven't done this in a production environment, but I've done it on my
> smp desktop box, and it seems to work okay.
>
>
>  -Jason
>

If you look at http://info.iet.unipi.it/~luigi/polling, the last Q & A 
question suggests why it is disabled for SMP.  It seems that polling 
only runs on one thread whereas an smp box might handle concurrently 
interupts from different devices.

Can the scheduler move the thread to another cpu or is it locked on a 
particular cpu?


Lucas Holt
Luke@FoolishGames.com
________________________________________________________
FoolishGames.com  (Jewel Fan Site)
JustJournal.com (Free blogging)



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