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Date: Mon, 25 Mar 2013 02:38:25 +0400
From: "Alexander V. Chernikov" <melifaro@FreeBSD.org>
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To: Eric van Gyzen <eric@vangyzen.net>
Subject: Re: [patch] IPMI KCS can drop the lock while servicing a request
References: <514E6ED8.9040305@vangyzen.net>
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On 24.03.2013 07:11, Eric van Gyzen wrote:
> At work, we discovered that our application's IPMI thread would often
> use a lot of CPU time. The KCS thread uses DELAY to wait for the BMC, so
> it can run without sleeping for a "long" time with a slow BMC. It also
> holds the ipmi_softc.ipmi_lock during this time. When using adaptive
> mutexes, an application thread that wants to operate on the
> ipmi_pending_requests list will also spin during this same time.
We suffer from the same problem, too.
>
> We see no reason that the KCS thread needs to hold the lock while
> servicing a request. We've been running with the attached patch for a
Well, this seems to be true. I'll try to commit something like this 
patch in several days.

> few months, with no ill effects.
>
> Eric
>
>
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