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Date: Mon, 10 Jan 2005 09:05:46 +0200
To: "M. Warner Losh" <imp@bsdimp.com>
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 <20050109.125213.02300240.imp@bsdimp.com>
 <41E1C8C5.4070605@elischer.org>
 <20050109.200910.28786915.imp@bsdimp.com>
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From: Boris Dinkevich <dinkevich@gmail.com>
cc: freebsd-usb@hub.freebsd.org
cc: dinkevich@gmail.com
cc: julian@elischer.org
Subject: Re: stack synchronization
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Hello everyone,

I see no reference to giant locking in 5.3 (except in event/task threads)

Does this not affect performance when multiple devices are connected to the 
host ?


Also, I have seen a modification to the bsd stack by Hans Petter Selasky, 
where he uses per bus mtxes for locking,
is this not the better approach to the problem ?

Interrupt is synced via Giant ?

Best Regards
Boris Dinkevich


At 05:09 AM 10/1/2005, M. Warner Losh wrote:
>In message: <41E1C8C5.4070605@elischer.org>
>             Julian Elischer <julian@elischer.org> writes:
>: M. Warner Losh wrote:
>: > In message: <6.1.2.0.2.20050109174427.0802c640@pop3>
>: >             Boris Dinkevich <dinkevich@gmail.com> writes:
>: > : Hello everyone,
>: > :
>: > : When going over the usb-host stack, it appears that synchronization 
>is done
>: > : via splusb/x.
>: > : But in the 5.3 release, these functions are implemented at stubs.
>: > :
>: > : How is the sync done then ?
>: > :
>: > : Also, with soft_interrupts, it appears there is no need for spls, am I
>: > : correct ?
>: >
>: > Giant locking.
>: >
>: > I have patches to move the interrupt outside of giant, but the rest of
>: > the stack is still under giant locking.
>:
>: it may be worth just adding a single "usb system" lock..
>
>well duh!  However, there's a lot of things that can trivially be done
>with giant.  Locking with a usb subsystem lock takes a lot more
>effort...
>
>Warner