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Date:      Mon, 16 Sep 2002 15:47:36 -0400 (EDT)
From:      John Baldwin <jhb@FreeBSD.org>
To:        Archie Cobbs <archie@dellroad.org>
Cc:        cvs-all@FreeBSD.org, cvs-committers@FreeBSD.org, "David O'Brien" <obrien@FreeBSD.org>, Josef Karthauser <joe@FreeBSD.org>, Bruce Evans <bde@zeta.org.au>, Poul-Henning Kamp <phk@critter.freebsd.dk>
Subject:   Re: cvs commit: src/sys/kern kern_timeout.c
Message-ID:  <XFMail.20020916154736.jhb@FreeBSD.org>
In-Reply-To: <200209161903.g8GJ3e687116@arch20m.dellroad.org>

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On 16-Sep-2002 Archie Cobbs wrote:
> Poul-Henning Kamp writes:
>> >> > Sep 15 19:40:26 kernel: Expensive timeout(9) function: 0xc65dfc80(0xc659f000) 0.008711721
>> >> > Sep 15 19:40:26 kernel: Expensive timeout(9) function: 0xc65dfc80(0xc659f000) 0.001068850
>> >
>> >This is hard to interpret without the function names (or a full stack
>> >trace).
>> 
>> Yes, but as far as I'm aware, we still don't have a print_backtrace(9) ?
>> 
>> >I get these on an old dual Celeron system mainly for fxp_tick()
>> >and uma_timeout().
>> 
>> uma_timeout() seems to trigger on practically all systems.
>> I've talked with Jeff about it already.
> 
> Would an option to timeout() like SPAWN_SEPARATE_THREAD be a practical
> solution for some of these cases? I.e., optionally spawn a separate
> thread to handle the timeout() event.
> 
> This may be expensive, but there may also be some timeout events that
> are rare, slow and expensive enough themselves to warrant using it.

You can have a timeout handler that just does a wakeup of a worker thread.
IWBN to include this type of functionality in the callout(9) API I suppose.

-- 

John Baldwin <jhb@FreeBSD.org>  <><  http://www.FreeBSD.org/~jhb/
"Power Users Use the Power to Serve!"  -  http://www.FreeBSD.org/

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