Re: [PATCH v2 00/25] AMDKFD kernel driver

From: Daniel Vetter
Date: Mon Jul 21 2014 - 14:22:28 EST


On Mon, Jul 21, 2014 at 7:28 PM, Oded Gabbay <oded.gabbay@xxxxxxx> wrote:
>> I'm not sure whether we can do the same trick with the hw scheduler. But
>> then unpinning hw contexts will drain the pipeline anyway, so I guess we
>> can just stop feeding the hw scheduler until it runs dry. And then unpin
>> and evict.
> So, I'm afraid but we can't do this for AMD Kaveri because:

Well as long as you can drain the hw scheduler queue (and you can do
that, worst case you have to unmap all the doorbells and other stuff
to intercept further submission from userspace) you can evict stuff.
And if we don't want compute to be a denial of service on the display
side of the driver we need this ability. Now if you go through an
ioctl instead of the doorbell (I agree with Jerome here, the doorbell
should be supported by benchmarks on linux) this gets a bit easier,
but it's not a requirement really.
-Daniel
--
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch
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