Am 12.10.2017 um 13:37 schrieb Liu, Monk:
> Hi team
> Very good, many policy and implement are agreed, looks we only have
> some arguments in amdgpu_ctx_query(), well I also confused with the
> current implement of it, â?¹
> First, I want to know if you guys agree that we*don't update
> ctx->reset_counter in amdgpu_ctx_query() *? because I want to make the
> query result always consistent upon a given context,
That sounds like a good idea to me, but I'm not sure if it won't break
userspace (I don't think so). Nicolai or Marek need to comment.
> Second, I want to say that for KERNEL, it shouldn't use the term from
> MESA or OGL or VULKAN, e.g. kernel shouldn't use AMDGPU_INNOCENT_RESET
> to map to GL_INNOCENT_RESET_ARB, etc...
> Because that way kernel will be very limited to certain UMD, so I
> suggest we totally re-name the context status, and each UMD has its
> own way to map the kernel context's result to gl-context/vk-context/etcâ?¦
Yes, completely agree.
> Kernel should only provide below **FLAG bits** on a given context:
>
> * Define AMDGPU_CTX_STATE_GUILTY 0x1 //as long as TDR
> detects a job hang, KMD set the context behind this context as
> "guilty"
> * Define AMDGPU_CTX_STATE_VRAMLOST 0x2 //as long as
> there is a VRAM lost event hit after this context created, we mark
> this context "VRAM_LOST", so UMD can say that all BO under this
> context may lost their content, since kernel have no relationship
> between context and BO so this is UMD's call to judge if a BO
> considered "VRAM lost" or not.
> * Define AMDGPU_CTX_STATE_RESET 0x3 //as long as there is a
> gpu reset occurred after context creation, this flag shall be set
>
That sounds sane, but unfortunately might not be possible with the
existing IOCTL. Keep in mind that we need to keep backward compatibility
here.
> Sample code:
> Int amdgpu_ctx_query(struct amdgpu_ctx_query_parm * out, â?¦..) {
> if (ctx- >vram_lost_counter != adev->vram_lost_counter)
> out- >status |= AMDGPU_CTX_STATE_VRAM_LOST;
> if (ctx- >reset_counter != adevâ??reset_counter){
> out- >status |= AMDGPU_CTX_STATE_RESET;
> if (ctx- >guilty == TRUE)
> out- >status |= AMDGPU_CTX_STATE_GUILTY;
> }
> return 0;
> }
> For UMD if it found "out.status == 0" means there is no gpu reset even
> occurred, the context is totally regular,
>
> * *A****new IOCTL added for context:*
>
> Void amdgpu_ctx_reinit(){
> Ctxâ??vram_lost_counter = adevâ??vram_lost_counter;
> Ctxâ??reset_counter = adevâ??reset_counter;
> }
Mhm, is there any advantage to just creating a new context?
Regards,
Christian.
> *if**UMD decide *not* to release the "guilty" context but continue
> using it **after**UMD acknowledged GPU hang **on certain job/context,
> I suggest **UMD call "amdgpu_ctx_reinit()":*
> That way after you re-init() this context, you can get updated result
> from "amdgpu_ctx_query", which will probably give you "out.status ==
> 0" as long as no gpu reset/vram lost hit after re-init().
> BR Monk
> -----Original Message-----
> From: Koenig, Christian
> Sent: 2017å¹´10æ??12æ?¥ 18:13
> To: Haehnle, Nicolai <Nicolai.Haehnle at amd.com>; Michel Dänzer
> <michel at daenzer.net>; Liu, Monk <Monk.Liu at amd.com>; Olsak, Marek
> <Marek.Olsak at amd.com>; Deucher, Alexander <Alexander.Deucher at amd.com>;
> Zhou, David(ChunMing) <David1.Zhou at amd.com>; Mao, David
> <David.Mao at amd.com>
> Cc: Ramirez, Alejandro <Alejandro.Ramirez at amd.com>;
> amd-gfx at lists.freedesktop.org; Filipas, Mario <Mario.Filipas at amd.com>;
> Ding, Pixel <Pixel.Ding at amd.com>; Li, Bingley <Bingley.Li at amd.com>;
> Jiang, Jerry (SW) <Jerry.Jiang at amd.com>
> Subject: Re: TDR and VRAM lost handling in KMD (v2)
> Am 12.10.2017 um 11:44 schrieb Nicolai Hähnle:
> > On 12.10.2017 11:35, Michel Dänzer wrote:
> >> On 12/10/17 11:23 AM, Christian König wrote:
> >>> Am 12.10.2017 um 11:10 schrieb Nicolai Hähnle:
> >>>> On 12.10.2017 10:49, Christian König wrote:
> >>>>>> However, !guilty && ctx->reset_counter != adev->reset_counter
> >>>>>> does not imply that the context was lost.
> >>>>>>
> >>>>>> The way I understand it, we should return
> >>>>>> AMDGPU_CTX_INNOCENT_RESET if !guilty && ctx->vram_lost_counter != adev->vram_lost_counter.
> >>>>>>
> >>>>>> As far as I understand it, the case of !guilty &&
> >>>>>> ctx->reset_counter != adev->reset_counter &&
> >>>>>> ctx->vram_lost_counter ==
> >>>>>> adev->vram_lost_counter should return AMDGPU_CTX_NO_RESET,
> >>>>>> adev->because a
> >>>>>> GPU reset occurred, but it didn't affect our context.
> >>>>> I disagree on that.
> >>>>>
> >>>>> AMDGPU_CTX_INNOCENT_RESET just means what it does currently, there
> >>>>> was a reset but we haven't been causing it.
> >>>>>
> >>>>> That the OpenGL extension is specified otherwise is unfortunate,
> >>>>> but I think we shouldn't use that for the kernel interface here.
> >>>> Two counterpoints:
> >>>>
> >>>> 1. Why should any application care that there was a reset while it
> >>>> was idle? The OpenGL behavior is what makes sense.
> >>>
> >>> The application is certainly not interest if a reset happened or
> >>> not, but I though that the driver stack might be.
> >>>
> >>>>
> >>>> 2. AMDGPU_CTX_INNOCENT_RESET doesn't actually mean anything today
> >>>> because we never return it :)
> >>>>
> >>>
> >>> Good point.
> >>>
> >>>> amdgpu_ctx_query only ever returns AMDGPU_CTX_UNKNOWN_RESET, which
> >>>> is in line with the OpenGL spec: we're conservatively returning
> >>>> that a reset happened because we don't know whether the context was
> >>>> affected, and we return UNKNOWN because we also don't know whether
> >>>> the context was guilty or not.
> >>>>
> >>>> Returning AMDGPU_CTX_NO_RESET in the case of !guilty &&
> >>>> ctx->vram_lost_counter == adev->vram_lost_counter is simply a
> >>>> refinement and improvement of the current, overly conservative
> >>>> behavior.
> >>>
> >>> Ok let's reenumerate what I think the different return values should
> >>> mean:
> >>>
> >>> * AMDGPU_CTX_GUILTY_RESET
> >>>
> >>> guilty is set to true for this context.
> >>>
> >>> * AMDGPU_CTX_INNOCENT_RESET
> >>>
> >>> guilty is not set and vram_lost_counter has changed.
> >>>
> >>> * AMDGPU_CTX_UNKNOWN_RESET
> >>>
> >>> guilty is not set and vram_lost_counter has not changed, but
> >>> gpu_reset_counter has changed.
> >>
> >> I don't understand the distinction you're proposing between
> >> AMDGPU_CTX_INNOCENT_RESET and AMDGPU_CTX_UNKNOWN_RESET. I think both
> >> cases you're describing should return either
> >> AMDGPU_CTX_INNOCENT_RESET, if the value of guilty is reliable, or
> >> AMDGPU_CTX_UNKNOWN_RESET if it's not.
> >
> > I think it'd make more sense if it was called
> > "AMDGPU_CTX_UNAFFECTED_RESET".
> >
> > So:
> > - AMDGPU_CTX_GUILTY_RESET --> the context was affected by a reset, and
> > we know that it's the context's fault
> > - AMDGPU_CTX_INNOCENT_RESET --> the context was affected by a reset,
> > and we know that it *wasn't* the context's fault (no context job
> > active)
> > - AMDGPU_CTX_UNKNOWN_RESET --> the context was affected by a reset,
> > and we don't know who's responsible (this could be returned in the
> > unlikely case where context A's gfx job has not yet finished, but
> > context B's gfx job has already started; it could be the fault of A,
> > it could be the fault of B -- which somehow manages to hang a part of
> > the hardware that then prevents A's job from finishing -- or it could
> > be both; but it's a bit academic)
> > - AMDGPU_CTX_UNAFFECTED_RESET --> there was a reset, but this context
> > wasn't affected
> >
> > This last value would currently just be discarded by Mesa (because we
> > should only disturb applications when we have to), but perhaps
> > somebody else could find it useful?
> Yes, that's what I had in mind as well.
> Cause otherwise we would return AMDGPU_CTX_NO_RESET while there
> actually was a reset and that certainly doesn't sound correct to me.
> Regards,
> Christian.
> >
> > Cheers,
> > Nicolai
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