Skip site navigation (1)Skip section navigation (2)
Date:      Tue, 31 May 2005 11:39:47 +1000 (EST)
From:      Bruce Evans <>
To:        Robert Watson <>
Subject:   Re: MPSAFE CAM?
Message-ID:  <>
In-Reply-To: <>

Next in thread | Previous in thread | Raw E-Mail | Index | Archive | Help
On Mon, 30 May 2005, Robert Watson wrote:

> On Mon, 30 May 2005, M. Warner Losh wrote:
>> In message: <>
>>            Robert Watson <> writes:
>> : driver, we've gained many of the benefits of making MPSAFE.  Especially 
>> if
>> : we can knock Giant off a lot of the remaining non-CAM device drivers that
>> : it's still stuck over.
>> usb, psm and atkbd are important ones for interactive performance...
> And the tty subsystem becomes an immediate dependency for several of these.

Interactive performance is irrelevant here.  You can can lose efficiency
by competing for Giant a few hundred thousand times in the time that
it takes an interactive user to notice.  The problem is that non-interactive
performance is impaired by using Giant locking anywhere.  Using it for
interactive devices is only a problem if the interaction often requires
holding Giant for a long time.  It doesn't for most input devices
including keyboards, but it might for slow bulk output devices like
syscons consoles.


Want to link to this message? Use this URL: <>