Re: [Intel-gfx] [PATCH 1/1] Let userspace know if they can trust timeslicing by including it as part of the I915_PARAM_HAS_SCHEDULER::I915_SCHEDULER_CAP_TIMESLICING
+ dri-devel as per process
On 25/05/2021 14:55, Tejas Upadhyay wrote:
v2: Only declare timeslicing if we can safely preempt userspace.
Commit message got butchered up somehow so you'll need to fix that at some point.
Regards,
Tvrtko
Fixes: 8ee36e048c98 ("drm/i915/execlists: Minimalistic timeslicing") Signed-off-by: Chris Wilson chris@chris-wilson.co.uk Cc: Tvrtko Ursulin tvrtko.ursulin@intel.com Reviewed-by: Tvrtko Ursulin tvrtko.ursulin@intel.com
drivers/gpu/drm/i915/gt/intel_engine_user.c | 1 + include/uapi/drm/i915_drm.h | 1 + 2 files changed, 2 insertions(+)
diff --git a/drivers/gpu/drm/i915/gt/intel_engine_user.c b/drivers/gpu/drm/i915/gt/intel_engine_user.c index 3cca7ea2d6ea..12d165566ed2 100644 --- a/drivers/gpu/drm/i915/gt/intel_engine_user.c +++ b/drivers/gpu/drm/i915/gt/intel_engine_user.c @@ -98,6 +98,7 @@ static void set_scheduler_caps(struct drm_i915_private *i915) MAP(HAS_PREEMPTION, PREEMPTION), MAP(HAS_SEMAPHORES, SEMAPHORES), MAP(SUPPORTS_STATS, ENGINE_BUSY_STATS),
MAP(TIMESLICE_BIT, TIMESLICING),diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h index c2c7759b7d2e..af2212d6113c 100644 --- a/include/uapi/drm/i915_drm.h +++ b/include/uapi/drm/i915_drm.h @@ -572,6 +572,7 @@ typedef struct drm_i915_irq_wait { #define I915_SCHEDULER_CAP_PREEMPTION (1ul << 2) #define I915_SCHEDULER_CAP_SEMAPHORES (1ul << 3) #define I915_SCHEDULER_CAP_ENGINE_BUSY_STATS (1ul << 4) +#define I915_SCHEDULER_CAP_TIMESLICING (1ul << 5)
#define I915_PARAM_HUC_STATUS 42
On Tue, May 25, 2021 at 03:19:47PM +0100, Tvrtko Ursulin wrote:
- dri-devel as per process
On 25/05/2021 14:55, Tejas Upadhyay wrote:
v2: Only declare timeslicing if we can safely preempt userspace.
Commit message got butchered up somehow so you'll need to fix that at some point.
Regards,
Tvrtko
Fixes: 8ee36e048c98 ("drm/i915/execlists: Minimalistic timeslicing") Signed-off-by: Chris Wilson chris@chris-wilson.co.uk Cc: Tvrtko Ursulin tvrtko.ursulin@intel.com Reviewed-by: Tvrtko Ursulin tvrtko.ursulin@intel.com
drivers/gpu/drm/i915/gt/intel_engine_user.c | 1 + include/uapi/drm/i915_drm.h | 1 + 2 files changed, 2 insertions(+)
diff --git a/drivers/gpu/drm/i915/gt/intel_engine_user.c b/drivers/gpu/drm/i915/gt/intel_engine_user.c index 3cca7ea2d6ea..12d165566ed2 100644 --- a/drivers/gpu/drm/i915/gt/intel_engine_user.c +++ b/drivers/gpu/drm/i915/gt/intel_engine_user.c @@ -98,6 +98,7 @@ static void set_scheduler_caps(struct drm_i915_private *i915) MAP(HAS_PREEMPTION, PREEMPTION), MAP(HAS_SEMAPHORES, SEMAPHORES), MAP(SUPPORTS_STATS, ENGINE_BUSY_STATS),
MAP(TIMESLICE_BIT, TIMESLICING),diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h index c2c7759b7d2e..af2212d6113c 100644 --- a/include/uapi/drm/i915_drm.h +++ b/include/uapi/drm/i915_drm.h @@ -572,6 +572,7 @@ typedef struct drm_i915_irq_wait { #define I915_SCHEDULER_CAP_PREEMPTION (1ul << 2) #define I915_SCHEDULER_CAP_SEMAPHORES (1ul << 3) #define I915_SCHEDULER_CAP_ENGINE_BUSY_STATS (1ul << 4) +#define I915_SCHEDULER_CAP_TIMESLICING (1ul << 5)
Since this is uapi I think we should at least have some nice kerneldoc that explains what exactly this is, what for (link to userspace) and all that. Ideally also minimally filing in the gaps in our uapi docs for stuff this references. -Daniel
#define I915_PARAM_HUC_STATUS 42
Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx
On 25/05/2021 15:47, Daniel Vetter wrote:
On Tue, May 25, 2021 at 03:19:47PM +0100, Tvrtko Ursulin wrote:
- dri-devel as per process
On 25/05/2021 14:55, Tejas Upadhyay wrote:
v2: Only declare timeslicing if we can safely preempt userspace.
Commit message got butchered up somehow so you'll need to fix that at some point.
Regards,
Tvrtko
Fixes: 8ee36e048c98 ("drm/i915/execlists: Minimalistic timeslicing") Signed-off-by: Chris Wilson chris@chris-wilson.co.uk Cc: Tvrtko Ursulin tvrtko.ursulin@intel.com Reviewed-by: Tvrtko Ursulin tvrtko.ursulin@intel.com
drivers/gpu/drm/i915/gt/intel_engine_user.c | 1 + include/uapi/drm/i915_drm.h | 1 + 2 files changed, 2 insertions(+)
diff --git a/drivers/gpu/drm/i915/gt/intel_engine_user.c b/drivers/gpu/drm/i915/gt/intel_engine_user.c index 3cca7ea2d6ea..12d165566ed2 100644 --- a/drivers/gpu/drm/i915/gt/intel_engine_user.c +++ b/drivers/gpu/drm/i915/gt/intel_engine_user.c @@ -98,6 +98,7 @@ static void set_scheduler_caps(struct drm_i915_private *i915) MAP(HAS_PREEMPTION, PREEMPTION), MAP(HAS_SEMAPHORES, SEMAPHORES), MAP(SUPPORTS_STATS, ENGINE_BUSY_STATS),
MAP(TIMESLICE_BIT, TIMESLICING),diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h index c2c7759b7d2e..af2212d6113c 100644 --- a/include/uapi/drm/i915_drm.h +++ b/include/uapi/drm/i915_drm.h @@ -572,6 +572,7 @@ typedef struct drm_i915_irq_wait { #define I915_SCHEDULER_CAP_PREEMPTION (1ul << 2) #define I915_SCHEDULER_CAP_SEMAPHORES (1ul << 3) #define I915_SCHEDULER_CAP_ENGINE_BUSY_STATS (1ul << 4) +#define I915_SCHEDULER_CAP_TIMESLICING (1ul << 5)
Since this is uapi I think we should at least have some nice kerneldoc that explains what exactly this is, what for (link to userspace) and all that. Ideally also minimally filing in the gaps in our uapi docs for stuff this references.
IIUC there is no userspace apart from IGT needing it not to fail scheduling tests on ADL.
Current tests use "has preemption + has semaphores" as a proxy to answer the "does the kernel support timeslicing" question. This stops working with the Guc backend because GuC decided not to support semaphores (for reasons yet unknown, see other thread), so explicit "has timeslicing" flag is needed in order for tests to know that GuC is supposed to support timeslicing, even if it doesn't use semaphores for inter-ring synchronisation.
Regards,
Tvrtko
On Wed, May 26, 2021 at 11:20:13AM +0100, Tvrtko Ursulin wrote:
On 25/05/2021 15:47, Daniel Vetter wrote:
On Tue, May 25, 2021 at 03:19:47PM +0100, Tvrtko Ursulin wrote:
- dri-devel as per process
On 25/05/2021 14:55, Tejas Upadhyay wrote:
v2: Only declare timeslicing if we can safely preempt userspace.
Commit message got butchered up somehow so you'll need to fix that at some point.
Regards,
Tvrtko
Fixes: 8ee36e048c98 ("drm/i915/execlists: Minimalistic timeslicing") Signed-off-by: Chris Wilson chris@chris-wilson.co.uk Cc: Tvrtko Ursulin tvrtko.ursulin@intel.com Reviewed-by: Tvrtko Ursulin tvrtko.ursulin@intel.com
drivers/gpu/drm/i915/gt/intel_engine_user.c | 1 + include/uapi/drm/i915_drm.h | 1 + 2 files changed, 2 insertions(+)
diff --git a/drivers/gpu/drm/i915/gt/intel_engine_user.c b/drivers/gpu/drm/i915/gt/intel_engine_user.c index 3cca7ea2d6ea..12d165566ed2 100644 --- a/drivers/gpu/drm/i915/gt/intel_engine_user.c +++ b/drivers/gpu/drm/i915/gt/intel_engine_user.c @@ -98,6 +98,7 @@ static void set_scheduler_caps(struct drm_i915_private *i915) MAP(HAS_PREEMPTION, PREEMPTION), MAP(HAS_SEMAPHORES, SEMAPHORES), MAP(SUPPORTS_STATS, ENGINE_BUSY_STATS),
MAP(TIMESLICE_BIT, TIMESLICING),diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h index c2c7759b7d2e..af2212d6113c 100644 --- a/include/uapi/drm/i915_drm.h +++ b/include/uapi/drm/i915_drm.h @@ -572,6 +572,7 @@ typedef struct drm_i915_irq_wait { #define I915_SCHEDULER_CAP_PREEMPTION (1ul << 2) #define I915_SCHEDULER_CAP_SEMAPHORES (1ul << 3) #define I915_SCHEDULER_CAP_ENGINE_BUSY_STATS (1ul << 4) +#define I915_SCHEDULER_CAP_TIMESLICING (1ul << 5)
Since this is uapi I think we should at least have some nice kerneldoc that explains what exactly this is, what for (link to userspace) and all that. Ideally also minimally filing in the gaps in our uapi docs for stuff this references.
IIUC there is no userspace apart from IGT needing it not to fail scheduling tests on ADL.
Current tests use "has preemption + has semaphores" as a proxy to answer the "does the kernel support timeslicing" question. This stops working with the Guc backend because GuC decided not to support semaphores (for reasons yet unknown, see other thread), so explicit "has timeslicing" flag is needed in order for tests to know that GuC is supposed to support timeslicing, even if it doesn't use semaphores for inter-ring synchronisation.
Since this if for igt only: Cant we do just extend the check in igt with an || GEN >= 12? I really hope that our future hw will continue to support timeslicing ...
Also if it's not there yet, a shared helper to check for that (like we're adding for relocations and stuff like that right now). -Daniel
On 27/05/2021 11:13, Daniel Vetter wrote:
On Wed, May 26, 2021 at 11:20:13AM +0100, Tvrtko Ursulin wrote:
On 25/05/2021 15:47, Daniel Vetter wrote:
On Tue, May 25, 2021 at 03:19:47PM +0100, Tvrtko Ursulin wrote:
- dri-devel as per process
On 25/05/2021 14:55, Tejas Upadhyay wrote:
v2: Only declare timeslicing if we can safely preempt userspace.
Commit message got butchered up somehow so you'll need to fix that at some point.
Regards,
Tvrtko
Fixes: 8ee36e048c98 ("drm/i915/execlists: Minimalistic timeslicing") Signed-off-by: Chris Wilson chris@chris-wilson.co.uk Cc: Tvrtko Ursulin tvrtko.ursulin@intel.com Reviewed-by: Tvrtko Ursulin tvrtko.ursulin@intel.com
drivers/gpu/drm/i915/gt/intel_engine_user.c | 1 + include/uapi/drm/i915_drm.h | 1 + 2 files changed, 2 insertions(+)diff --git a/drivers/gpu/drm/i915/gt/intel_engine_user.c b/drivers/gpu/drm/i915/gt/intel_engine_user.c index 3cca7ea2d6ea..12d165566ed2 100644 --- a/drivers/gpu/drm/i915/gt/intel_engine_user.c +++ b/drivers/gpu/drm/i915/gt/intel_engine_user.c @@ -98,6 +98,7 @@ static void set_scheduler_caps(struct drm_i915_private *i915) MAP(HAS_PREEMPTION, PREEMPTION), MAP(HAS_SEMAPHORES, SEMAPHORES), MAP(SUPPORTS_STATS, ENGINE_BUSY_STATS),
MAP(TIMESLICE_BIT, TIMESLICING),diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h index c2c7759b7d2e..af2212d6113c 100644 --- a/include/uapi/drm/i915_drm.h +++ b/include/uapi/drm/i915_drm.h @@ -572,6 +572,7 @@ typedef struct drm_i915_irq_wait { #define I915_SCHEDULER_CAP_PREEMPTION (1ul << 2) #define I915_SCHEDULER_CAP_SEMAPHORES (1ul << 3) #define I915_SCHEDULER_CAP_ENGINE_BUSY_STATS (1ul << 4) +#define I915_SCHEDULER_CAP_TIMESLICING (1ul << 5)
Since this is uapi I think we should at least have some nice kerneldoc that explains what exactly this is, what for (link to userspace) and all that. Ideally also minimally filing in the gaps in our uapi docs for stuff this references.
IIUC there is no userspace apart from IGT needing it not to fail scheduling tests on ADL.
Current tests use "has preemption + has semaphores" as a proxy to answer the "does the kernel support timeslicing" question. This stops working with the Guc backend because GuC decided not to support semaphores (for reasons yet unknown, see other thread), so explicit "has timeslicing" flag is needed in order for tests to know that GuC is supposed to support timeslicing, even if it doesn't use semaphores for inter-ring synchronisation.
Since this if for igt only: Cant we do just extend the check in igt with an || GEN >= 12? I really hope that our future hw will continue to support timeslicing ...
Not the gen 12 check, but possible I think. Explicit feature test would be better, but if definitely not allowed then along the lines of:
has_timeslicing = (has_preemption && has_semaphores) || uses_guc_submission;
Regards,
Tvrtko
Also if it's not there yet, a shared helper to check for that (like we're adding for relocations and stuff like that right now). -Daniel
On Thu, May 27, 2021 at 11:22:16AM +0100, Tvrtko Ursulin wrote:
On 27/05/2021 11:13, Daniel Vetter wrote:
On Wed, May 26, 2021 at 11:20:13AM +0100, Tvrtko Ursulin wrote:
On 25/05/2021 15:47, Daniel Vetter wrote:
On Tue, May 25, 2021 at 03:19:47PM +0100, Tvrtko Ursulin wrote:
- dri-devel as per process
On 25/05/2021 14:55, Tejas Upadhyay wrote:
v2: Only declare timeslicing if we can safely preempt userspace.
Commit message got butchered up somehow so you'll need to fix that at some point.
Regards,
Tvrtko
Fixes: 8ee36e048c98 ("drm/i915/execlists: Minimalistic timeslicing") Signed-off-by: Chris Wilson chris@chris-wilson.co.uk Cc: Tvrtko Ursulin tvrtko.ursulin@intel.com Reviewed-by: Tvrtko Ursulin tvrtko.ursulin@intel.com
drivers/gpu/drm/i915/gt/intel_engine_user.c | 1 + include/uapi/drm/i915_drm.h | 1 + 2 files changed, 2 insertions(+)diff --git a/drivers/gpu/drm/i915/gt/intel_engine_user.c b/drivers/gpu/drm/i915/gt/intel_engine_user.c index 3cca7ea2d6ea..12d165566ed2 100644 --- a/drivers/gpu/drm/i915/gt/intel_engine_user.c +++ b/drivers/gpu/drm/i915/gt/intel_engine_user.c @@ -98,6 +98,7 @@ static void set_scheduler_caps(struct drm_i915_private *i915) MAP(HAS_PREEMPTION, PREEMPTION), MAP(HAS_SEMAPHORES, SEMAPHORES), MAP(SUPPORTS_STATS, ENGINE_BUSY_STATS),
MAP(TIMESLICE_BIT, TIMESLICING),diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h index c2c7759b7d2e..af2212d6113c 100644 --- a/include/uapi/drm/i915_drm.h +++ b/include/uapi/drm/i915_drm.h @@ -572,6 +572,7 @@ typedef struct drm_i915_irq_wait { #define I915_SCHEDULER_CAP_PREEMPTION (1ul << 2) #define I915_SCHEDULER_CAP_SEMAPHORES (1ul << 3) #define I915_SCHEDULER_CAP_ENGINE_BUSY_STATS (1ul << 4) +#define I915_SCHEDULER_CAP_TIMESLICING (1ul << 5)
Since this is uapi I think we should at least have some nice kerneldoc that explains what exactly this is, what for (link to userspace) and all that. Ideally also minimally filing in the gaps in our uapi docs for stuff this references.
IIUC there is no userspace apart from IGT needing it not to fail scheduling tests on ADL.
Current tests use "has preemption + has semaphores" as a proxy to answer the "does the kernel support timeslicing" question. This stops working with the Guc backend because GuC decided not to support semaphores (for reasons yet unknown, see other thread), so explicit "has timeslicing" flag is needed in order for tests to know that GuC is supposed to support timeslicing, even if it doesn't use semaphores for inter-ring synchronisation.
Since this if for igt only: Cant we do just extend the check in igt with an || GEN >= 12? I really hope that our future hw will continue to support timeslicing ...
Not the gen 12 check, but possible I think. Explicit feature test would be better, but if definitely not allowed then along the lines of:
has_timeslicing = (has_preemption && has_semaphores) || uses_guc_submission;
That works too. Otoh what exactly is the "uses guc submission" flag and why do we have that? I've seen media use it as a stand-in for "does the kernel want bonded or parallel ctx?". Maybe another thing to check.
Another option, if you really think the feature flag is the best approach (because future hw will drop timeslicing for some reason), then debugfs is the place of igt-only api. -Daniel
Regards,
Tvrtko
Also if it's not there yet, a shared helper to check for that (like we're adding for relocations and stuff like that right now). -Daniel
On 27/05/2021 11:27, Daniel Vetter wrote:
On Thu, May 27, 2021 at 11:22:16AM +0100, Tvrtko Ursulin wrote:
On 27/05/2021 11:13, Daniel Vetter wrote:
On Wed, May 26, 2021 at 11:20:13AM +0100, Tvrtko Ursulin wrote:
On 25/05/2021 15:47, Daniel Vetter wrote:
On Tue, May 25, 2021 at 03:19:47PM +0100, Tvrtko Ursulin wrote:
- dri-devel as per process
On 25/05/2021 14:55, Tejas Upadhyay wrote: > v2: Only declare timeslicing if we can safely preempt userspace.
Commit message got butchered up somehow so you'll need to fix that at some point.
Regards,
Tvrtko
> Fixes: 8ee36e048c98 ("drm/i915/execlists: Minimalistic timeslicing") > Signed-off-by: Chris Wilson chris@chris-wilson.co.uk > Cc: Tvrtko Ursulin tvrtko.ursulin@intel.com > Reviewed-by: Tvrtko Ursulin tvrtko.ursulin@intel.com > --- > drivers/gpu/drm/i915/gt/intel_engine_user.c | 1 + > include/uapi/drm/i915_drm.h | 1 + > 2 files changed, 2 insertions(+) > > diff --git a/drivers/gpu/drm/i915/gt/intel_engine_user.c b/drivers/gpu/drm/i915/gt/intel_engine_user.c > index 3cca7ea2d6ea..12d165566ed2 100644 > --- a/drivers/gpu/drm/i915/gt/intel_engine_user.c > +++ b/drivers/gpu/drm/i915/gt/intel_engine_user.c > @@ -98,6 +98,7 @@ static void set_scheduler_caps(struct drm_i915_private *i915) > MAP(HAS_PREEMPTION, PREEMPTION), > MAP(HAS_SEMAPHORES, SEMAPHORES), > MAP(SUPPORTS_STATS, ENGINE_BUSY_STATS), > + MAP(TIMESLICE_BIT, TIMESLICING), > #undef MAP > }; > struct intel_engine_cs *engine; > diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h > index c2c7759b7d2e..af2212d6113c 100644 > --- a/include/uapi/drm/i915_drm.h > +++ b/include/uapi/drm/i915_drm.h > @@ -572,6 +572,7 @@ typedef struct drm_i915_irq_wait { > #define I915_SCHEDULER_CAP_PREEMPTION (1ul << 2) > #define I915_SCHEDULER_CAP_SEMAPHORES (1ul << 3) > #define I915_SCHEDULER_CAP_ENGINE_BUSY_STATS (1ul << 4) > +#define I915_SCHEDULER_CAP_TIMESLICING (1ul << 5)
Since this is uapi I think we should at least have some nice kerneldoc that explains what exactly this is, what for (link to userspace) and all that. Ideally also minimally filing in the gaps in our uapi docs for stuff this references.
IIUC there is no userspace apart from IGT needing it not to fail scheduling tests on ADL.
Current tests use "has preemption + has semaphores" as a proxy to answer the "does the kernel support timeslicing" question. This stops working with the Guc backend because GuC decided not to support semaphores (for reasons yet unknown, see other thread), so explicit "has timeslicing" flag is needed in order for tests to know that GuC is supposed to support timeslicing, even if it doesn't use semaphores for inter-ring synchronisation.
Since this if for igt only: Cant we do just extend the check in igt with an || GEN >= 12? I really hope that our future hw will continue to support timeslicing ...
Not the gen 12 check, but possible I think. Explicit feature test would be better, but if definitely not allowed then along the lines of:
has_timeslicing = (has_preemption && has_semaphores) || uses_guc_submission;
That works too. Otoh what exactly is the "uses guc submission" flag and why do we have that? I've seen media use it as a stand-in for "does the kernel want bonded or parallel ctx?". Maybe another thing to check.
IGT derives it from the enable_guc modparam and logs it during test start (some tests). It's called actuall gem_submission_method(_..). It's useful to have as long as there are platforms where submission backend can be picked at runtime. Afterwards not so much I guess.
Regards,
Tvrtko
Another option, if you really think the feature flag is the best approach (because future hw will drop timeslicing for some reason), then debugfs is the place of igt-only api. -Daniel
Regards,
Tvrtko
Also if it's not there yet, a shared helper to check for that (like we're adding for relocations and stuff like that right now). -Daniel
On 27/05/2021 11:27, Daniel Vetter wrote:
On Thu, May 27, 2021 at 11:22:16AM +0100, Tvrtko Ursulin wrote:
On 27/05/2021 11:13, Daniel Vetter wrote:
On Wed, May 26, 2021 at 11:20:13AM +0100, Tvrtko Ursulin wrote:
On 25/05/2021 15:47, Daniel Vetter wrote:
On Tue, May 25, 2021 at 03:19:47PM +0100, Tvrtko Ursulin wrote:
- dri-devel as per process
On 25/05/2021 14:55, Tejas Upadhyay wrote: > v2: Only declare timeslicing if we can safely preempt userspace.
Commit message got butchered up somehow so you'll need to fix that at some point.
Regards,
Tvrtko
> Fixes: 8ee36e048c98 ("drm/i915/execlists: Minimalistic timeslicing") > Signed-off-by: Chris Wilson chris@chris-wilson.co.uk > Cc: Tvrtko Ursulin tvrtko.ursulin@intel.com > Reviewed-by: Tvrtko Ursulin tvrtko.ursulin@intel.com > --- > drivers/gpu/drm/i915/gt/intel_engine_user.c | 1 + > include/uapi/drm/i915_drm.h | 1 + > 2 files changed, 2 insertions(+) > > diff --git a/drivers/gpu/drm/i915/gt/intel_engine_user.c b/drivers/gpu/drm/i915/gt/intel_engine_user.c > index 3cca7ea2d6ea..12d165566ed2 100644 > --- a/drivers/gpu/drm/i915/gt/intel_engine_user.c > +++ b/drivers/gpu/drm/i915/gt/intel_engine_user.c > @@ -98,6 +98,7 @@ static void set_scheduler_caps(struct drm_i915_private *i915) > MAP(HAS_PREEMPTION, PREEMPTION), > MAP(HAS_SEMAPHORES, SEMAPHORES), > MAP(SUPPORTS_STATS, ENGINE_BUSY_STATS), > + MAP(TIMESLICE_BIT, TIMESLICING), > #undef MAP > }; > struct intel_engine_cs *engine; > diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h > index c2c7759b7d2e..af2212d6113c 100644 > --- a/include/uapi/drm/i915_drm.h > +++ b/include/uapi/drm/i915_drm.h > @@ -572,6 +572,7 @@ typedef struct drm_i915_irq_wait { > #define I915_SCHEDULER_CAP_PREEMPTION (1ul << 2) > #define I915_SCHEDULER_CAP_SEMAPHORES (1ul << 3) > #define I915_SCHEDULER_CAP_ENGINE_BUSY_STATS (1ul << 4) > +#define I915_SCHEDULER_CAP_TIMESLICING (1ul << 5)
Since this is uapi I think we should at least have some nice kerneldoc that explains what exactly this is, what for (link to userspace) and all that. Ideally also minimally filing in the gaps in our uapi docs for stuff this references.
IIUC there is no userspace apart from IGT needing it not to fail scheduling tests on ADL.
Current tests use "has preemption + has semaphores" as a proxy to answer the "does the kernel support timeslicing" question. This stops working with the Guc backend because GuC decided not to support semaphores (for reasons yet unknown, see other thread), so explicit "has timeslicing" flag is needed in order for tests to know that GuC is supposed to support timeslicing, even if it doesn't use semaphores for inter-ring synchronisation.
Since this if for igt only: Cant we do just extend the check in igt with an || GEN >= 12? I really hope that our future hw will continue to support timeslicing ...
Not the gen 12 check, but possible I think. Explicit feature test would be better, but if definitely not allowed then along the lines of:
has_timeslicing = (has_preemption && has_semaphores) || uses_guc_submission;
That works too. Otoh what exactly is the "uses guc submission" flag and why do we have that? I've seen media use it as a stand-in for "does the kernel want bonded or parallel ctx?". Maybe another thing to check.
Another option, if you really think the feature flag is the best approach (because future hw will drop timeslicing for some reason), then debugfs is the place of igt-only api.
Maybe check and potentially remove all I915_SCHEDULER_CAP_.. flags. It could be another easy pickings with a lot of IGT work type endeavour.
Regards,
Tvrtko
On Tue, Jun 01, 2021 at 11:09:47AM +0100, Tvrtko Ursulin wrote:
On 27/05/2021 11:27, Daniel Vetter wrote:
On Thu, May 27, 2021 at 11:22:16AM +0100, Tvrtko Ursulin wrote:
On 27/05/2021 11:13, Daniel Vetter wrote:
On Wed, May 26, 2021 at 11:20:13AM +0100, Tvrtko Ursulin wrote:
On 25/05/2021 15:47, Daniel Vetter wrote:
On Tue, May 25, 2021 at 03:19:47PM +0100, Tvrtko Ursulin wrote: > > + dri-devel as per process > > On 25/05/2021 14:55, Tejas Upadhyay wrote: > > v2: Only declare timeslicing if we can safely preempt userspace. > > Commit message got butchered up somehow so you'll need to fix that at some > point. > > Regards, > > Tvrtko > > > Fixes: 8ee36e048c98 ("drm/i915/execlists: Minimalistic timeslicing") > > Signed-off-by: Chris Wilson chris@chris-wilson.co.uk > > Cc: Tvrtko Ursulin tvrtko.ursulin@intel.com > > Reviewed-by: Tvrtko Ursulin tvrtko.ursulin@intel.com > > --- > > drivers/gpu/drm/i915/gt/intel_engine_user.c | 1 + > > include/uapi/drm/i915_drm.h | 1 + > > 2 files changed, 2 insertions(+) > > > > diff --git a/drivers/gpu/drm/i915/gt/intel_engine_user.c b/drivers/gpu/drm/i915/gt/intel_engine_user.c > > index 3cca7ea2d6ea..12d165566ed2 100644 > > --- a/drivers/gpu/drm/i915/gt/intel_engine_user.c > > +++ b/drivers/gpu/drm/i915/gt/intel_engine_user.c > > @@ -98,6 +98,7 @@ static void set_scheduler_caps(struct drm_i915_private *i915) > > MAP(HAS_PREEMPTION, PREEMPTION), > > MAP(HAS_SEMAPHORES, SEMAPHORES), > > MAP(SUPPORTS_STATS, ENGINE_BUSY_STATS), > > + MAP(TIMESLICE_BIT, TIMESLICING), > > #undef MAP > > }; > > struct intel_engine_cs *engine; > > diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h > > index c2c7759b7d2e..af2212d6113c 100644 > > --- a/include/uapi/drm/i915_drm.h > > +++ b/include/uapi/drm/i915_drm.h > > @@ -572,6 +572,7 @@ typedef struct drm_i915_irq_wait { > > #define I915_SCHEDULER_CAP_PREEMPTION (1ul << 2) > > #define I915_SCHEDULER_CAP_SEMAPHORES (1ul << 3) > > #define I915_SCHEDULER_CAP_ENGINE_BUSY_STATS (1ul << 4) > > +#define I915_SCHEDULER_CAP_TIMESLICING (1ul << 5)
Since this is uapi I think we should at least have some nice kerneldoc that explains what exactly this is, what for (link to userspace) and all that. Ideally also minimally filing in the gaps in our uapi docs for stuff this references.
IIUC there is no userspace apart from IGT needing it not to fail scheduling tests on ADL.
Current tests use "has preemption + has semaphores" as a proxy to answer the "does the kernel support timeslicing" question. This stops working with the Guc backend because GuC decided not to support semaphores (for reasons yet unknown, see other thread), so explicit "has timeslicing" flag is needed in order for tests to know that GuC is supposed to support timeslicing, even if it doesn't use semaphores for inter-ring synchronisation.
Since this if for igt only: Cant we do just extend the check in igt with an || GEN >= 12? I really hope that our future hw will continue to support timeslicing ...
Not the gen 12 check, but possible I think. Explicit feature test would be better, but if definitely not allowed then along the lines of:
has_timeslicing = (has_preemption && has_semaphores) || uses_guc_submission;
That works too. Otoh what exactly is the "uses guc submission" flag and why do we have that? I've seen media use it as a stand-in for "does the kernel want bonded or parallel ctx?". Maybe another thing to check.
Another option, if you really think the feature flag is the best approach (because future hw will drop timeslicing for some reason), then debugfs is the place of igt-only api.
Maybe check and potentially remove all I915_SCHEDULER_CAP_.. flags. It could be another easy pickings with a lot of IGT work type endeavour.
Yeah there's a lot unfortunately. I'll make a note internally that we need to look at this again maybe next year, but for now we're going to only concentrate on stuff that has actual architecture/design impact. In the grand scheme of things exporting a bunch of flags for igt in the uapi is mostly harmless. There's much bigger fish to fry were we allow igt to make changes to objects that should be all immutable. Those need to be worked out first. -Daniel
On 27/05/2021 11:22, Tvrtko Ursulin wrote:
On 27/05/2021 11:13, Daniel Vetter wrote:
On Wed, May 26, 2021 at 11:20:13AM +0100, Tvrtko Ursulin wrote:
On 25/05/2021 15:47, Daniel Vetter wrote:
On Tue, May 25, 2021 at 03:19:47PM +0100, Tvrtko Ursulin wrote:
- dri-devel as per process
On 25/05/2021 14:55, Tejas Upadhyay wrote:
v2: Only declare timeslicing if we can safely preempt userspace.
Commit message got butchered up somehow so you'll need to fix that at some point.
Regards,
Tvrtko
Fixes: 8ee36e048c98 ("drm/i915/execlists: Minimalistic timeslicing") Signed-off-by: Chris Wilson chris@chris-wilson.co.uk Cc: Tvrtko Ursulin tvrtko.ursulin@intel.com Reviewed-by: Tvrtko Ursulin tvrtko.ursulin@intel.com
drivers/gpu/drm/i915/gt/intel_engine_user.c | 1 + include/uapi/drm/i915_drm.h | 1 + 2 files changed, 2 insertions(+)
diff --git a/drivers/gpu/drm/i915/gt/intel_engine_user.c b/drivers/gpu/drm/i915/gt/intel_engine_user.c index 3cca7ea2d6ea..12d165566ed2 100644 --- a/drivers/gpu/drm/i915/gt/intel_engine_user.c +++ b/drivers/gpu/drm/i915/gt/intel_engine_user.c @@ -98,6 +98,7 @@ static void set_scheduler_caps(struct drm_i915_private *i915) MAP(HAS_PREEMPTION, PREEMPTION), MAP(HAS_SEMAPHORES, SEMAPHORES), MAP(SUPPORTS_STATS, ENGINE_BUSY_STATS), + MAP(TIMESLICE_BIT, TIMESLICING), #undef MAP }; struct intel_engine_cs *engine; diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h index c2c7759b7d2e..af2212d6113c 100644 --- a/include/uapi/drm/i915_drm.h +++ b/include/uapi/drm/i915_drm.h @@ -572,6 +572,7 @@ typedef struct drm_i915_irq_wait { #define I915_SCHEDULER_CAP_PREEMPTION (1ul << 2) #define I915_SCHEDULER_CAP_SEMAPHORES (1ul << 3) #define I915_SCHEDULER_CAP_ENGINE_BUSY_STATS (1ul << 4) +#define I915_SCHEDULER_CAP_TIMESLICING (1ul << 5)
Since this is uapi I think we should at least have some nice kerneldoc that explains what exactly this is, what for (link to userspace) and all that. Ideally also minimally filing in the gaps in our uapi docs for stuff this references.
IIUC there is no userspace apart from IGT needing it not to fail scheduling tests on ADL.
Current tests use "has preemption + has semaphores" as a proxy to answer the "does the kernel support timeslicing" question. This stops working with the Guc backend because GuC decided not to support semaphores (for reasons yet unknown, see other thread), so explicit "has timeslicing" flag is needed in order for tests to know that GuC is supposed to support timeslicing, even if it doesn't use semaphores for inter-ring synchronisation.
Since this if for igt only: Cant we do just extend the check in igt with an || GEN >= 12? I really hope that our future hw will continue to support timeslicing ...
Not the gen 12 check, but possible I think. Explicit feature test would be better, but if definitely not allowed then along the lines of:
has_timeslicing = (has_preemption && has_semaphores) || uses_guc_submission;
One catch is that timeslicing in GuC will be disabled both if at compile time CONFIG_DRM_I915_TIMESLICE_DURATION is set to zero, or if at runtime engine->props.timeslice_duration_ms is equally set to zero.
So I think what is needed on top of the above check is to walk all engines in sysfs and check that timeslicing hasn't explicitly been disabled for any one of them.
If we are talking about the global flag at least. Per engine tests could do better I guess, but I don't think that complication is worth the effort.
Regards,
Tvrtko
dri-devel@lists.freedesktop.org
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Daniel Vetter -
Tvrtko Ursulin