Re: [RFC 03/11] drm/i915: Add reset stats entry point for per-engine reset.

Tomas Elf
2015-06-09T11:06:49Z

On 08/06/2015 18:33, Chris Wilson wrote:
> On Mon, Jun 08, 2015 at 06:03:21PM +0100, Tomas Elf wrote:
>> In preparation for per-engine reset add way for setting context reset stats.
>>
>> OPEN QUESTIONS:
>> 1. How do we deal with get_reset_stats and the GL robustness interface when
>> introducing per-engine resets?
>>
>> a. Do we set context that cause per-engine resets as guilty? If so, how
>> does this affect context banning?
>
> Yes. If the reset works quicker, then we can set a higher threshold for
> DoS detection, but we still do need Dos detection?

Cool, as long as we make sure to set the context banning period such
that we allow at least one per-engine recovery attempt and one full GPU
reset attempt to be made. Or set it any way that would not effectively
disable any initial hang recovery attempt.

I'll replicate the behavior from the legacy full GPU reset path in the
engine reset path then.

Thanks,
Tomas

>
>> b. Do we extend the publically available reset stats to also contain
>> per-engine reset statistics? If so, would this break the ABI?
>
> No. The get_reset_stats is targetted at the GL API and describing it in
> terms of whether my context is guilty or has been affected. That is
> orthogonal to whether the reset was on a single ring or the entire GPU -
> the question is how broad do want the "affected" to be. Ideally a
> per-context reset wouldn't necessarily impact others, except for the
> surfaces shared between them...
> -Chris