GPU lockup dumping

[Jerome Glisse]

On Wed, May 23, 2012 at 12:08 PM, Dave Airlie <airlied at gmail.com> wrote:
> On Wed, May 23, 2012 at 3:48 PM, Jerome Glisse <j.glisse at gmail.com> wrote:
>> On Wed, May 23, 2012 at 8:34 AM, Christian König
>> <deathsimple at vodafone.de> wrote:
>>> On 23.05.2012 11:27, Dave Airlie wrote:
>>>>
>>>> On Thu, May 17, 2012 at 7:28 PM,<j.glisse at gmail.com>  wrote:
>>>>>
>>>>> So here is improved patchset, where i splited ground work necessary
>>>>> for the dumping into their own patch. The debugfs improvement could
>>>>> probably be usefull to intel instead of having i915 have it's own
>>>>> debugfs file stuff.
>>>>>
>>>>> The lockup dumping public api have been move into radeon_drm.h
>>>>>
>>>>> Stressing the fact again that dump are self contained ie they have
>>>>> all the data needed to be replayed (vertex, indices, shader, texture,
>>>>> ...).
>>>>>
>>>>> Would really like to get this into 3.5, the new API is pretty much
>>>>> straightforward and userspace tools can easily be made to convert
>>>>> it to other format. The change to the driver is self contained.
>>>>
>>>> I really don't like introducing this at this stage into 3.5,
>>>>
>>>> I'd really like a good review of the API and what information we provide
>>>> along with how extensible it is.
>>>>
>>>> I'm still not convinced replay is what we want in the field, I know its
>>>> what
>>>> *you* want, but I think apitrace stuff in userspace pretty much covers
>>>> the replaying situation. So I'd have to look at this and see how easy
>>>> it makes disecting command streams etc.
>>>>
>>>> Dave.
>>>
>>>
>>> I agree that it might not be a good idea to push that into 3.5, since at
>>> least I (and I also think Alex) didn't had time to look into it yet. On the
>>> other hand the patches look quite reasonable.
>>>
>>> But I still wanted to throw in a requirement from my day to day work, maybe
>>> that helps finding a more general solution:
>>> When we start to work with more parts of the chip it might be necessary to
>>> dump everything that is currently "in the fly". For example I had a whole
>>> bunch of problems where copying data around with a 3D Blit and then missing
>>> a sync between this job and a job on another rings causes a "hiccup" in the
>>> hardware.
>>>
>>> I know that this isn't your focus and that is absolutely ok with me, cause
>>> the format you are introducing is just used in debugfs and so not part of
>>> any stable API (at least not in my understanding), but you should still keep
>>> in mind that we might need to extend it into that direction in the future.
>>>
>>> Christian.
>>
>> Note that my format is also done with that in mind, it can capture ib
>> from all rings. The only thing i don't think worth capturing are the
>> ring themself because there would be no way to replay them without
>> adding some new special API.
>
> I'd like to dump the rings as well, as I said I'd rather we didn't
> limit this to replay, but make it useful for getting as much info as
> possible out
>
> Dave.

Ring will contains very little, like ib schedule and fence, i don't
see how useful this can be.

Cheers,
Jerome