| Message ID | 20210624070516.21893-21-matthew.brost@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | GuC submission support | expand |
On 6/24/2021 00:04, Matthew Brost wrote: > Semaphores are an optimization and not required for basic GuC submission > to work properly. Disable until we have time to do the implementation to > enable semaphores and tune them for performance. Also long direction is > just to delete semaphores from the i915 so another reason to not enable > these for GuC submission. > > v2: Reword commit message > > Cc: John Harrison <john.c.harrison@intel.com> > Signed-off-by: Matthew Brost <matthew.brost@intel.com> I think the commit description does not really match the patch content. The description is valid but the 'disable' is done by simply not setting the enable flag (done in the execlist back end and presumably not done in the GuC back end). However, what the patch is actually doing seems to be fixing bugs with the 'are semaphores enabled' mechanism. I.e. correcting pieces of code that used semaphores without checking if they are enabled. And presumably this would be broken if someone tried to disable semaphores in execlist mode for any reason? So I think keeping the existing comment text is fine but something should be added to explain the actual changes. John. > --- > drivers/gpu/drm/i915/gem/i915_gem_context.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c b/drivers/gpu/drm/i915/gem/i915_gem_context.c > index 7720b8c22c81..5c07e6abf16a 100644 > --- a/drivers/gpu/drm/i915/gem/i915_gem_context.c > +++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c > @@ -230,7 +230,8 @@ static void intel_context_set_gem(struct intel_context *ce, > ce->timeline = intel_timeline_get(ctx->timeline); > > if (ctx->sched.priority >= I915_PRIORITY_NORMAL && > - intel_engine_has_timeslices(ce->engine)) > + intel_engine_has_timeslices(ce->engine) && > + intel_engine_has_semaphores(ce->engine)) > __set_bit(CONTEXT_USE_SEMAPHORES, &ce->flags); > > intel_context_set_watchdog_us(ce, ctx->watchdog.timeout_us); > @@ -1938,7 +1939,8 @@ static int __apply_priority(struct intel_context *ce, void *arg) > if (!intel_engine_has_timeslices(ce->engine)) > return 0; > > - if (ctx->sched.priority >= I915_PRIORITY_NORMAL) > + if (ctx->sched.priority >= I915_PRIORITY_NORMAL && > + intel_engine_has_semaphores(ce->engine)) > intel_context_set_use_semaphores(ce); > else > intel_context_clear_use_semaphores(ce);
On Fri, Jul 09, 2021 at 04:53:37PM -0700, John Harrison wrote: > On 6/24/2021 00:04, Matthew Brost wrote: > > Semaphores are an optimization and not required for basic GuC submission > > to work properly. Disable until we have time to do the implementation to > > enable semaphores and tune them for performance. Also long direction is > > just to delete semaphores from the i915 so another reason to not enable > > these for GuC submission. > > > > v2: Reword commit message > > > > Cc: John Harrison <john.c.harrison@intel.com> > > Signed-off-by: Matthew Brost <matthew.brost@intel.com> > I think the commit description does not really match the patch content. The > description is valid but the 'disable' is done by simply not setting the > enable flag (done in the execlist back end and presumably not done in the > GuC back end). However, what the patch is actually doing seems to be fixing > bugs with the 'are semaphores enabled' mechanism. I.e. correcting pieces of > code that used semaphores without checking if they are enabled. And > presumably this would be broken if someone tried to disable semaphores in > execlist mode for any reason? > > So I think keeping the existing comment text is fine but something should be > added to explain the actual changes. > Yes, commit is wrong. This more or less bug fix to the existing code. Will update. Matt > John. > > > > --- > > drivers/gpu/drm/i915/gem/i915_gem_context.c | 6 ++++-- > > 1 file changed, 4 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c b/drivers/gpu/drm/i915/gem/i915_gem_context.c > > index 7720b8c22c81..5c07e6abf16a 100644 > > --- a/drivers/gpu/drm/i915/gem/i915_gem_context.c > > +++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c > > @@ -230,7 +230,8 @@ static void intel_context_set_gem(struct intel_context *ce, > > ce->timeline = intel_timeline_get(ctx->timeline); > > if (ctx->sched.priority >= I915_PRIORITY_NORMAL && > > - intel_engine_has_timeslices(ce->engine)) > > + intel_engine_has_timeslices(ce->engine) && > > + intel_engine_has_semaphores(ce->engine)) > > __set_bit(CONTEXT_USE_SEMAPHORES, &ce->flags); > > intel_context_set_watchdog_us(ce, ctx->watchdog.timeout_us); > > @@ -1938,7 +1939,8 @@ static int __apply_priority(struct intel_context *ce, void *arg) > > if (!intel_engine_has_timeslices(ce->engine)) > > return 0; > > - if (ctx->sched.priority >= I915_PRIORITY_NORMAL) > > + if (ctx->sched.priority >= I915_PRIORITY_NORMAL && > > + intel_engine_has_semaphores(ce->engine)) > > intel_context_set_use_semaphores(ce); > > else > > intel_context_clear_use_semaphores(ce); >
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c b/drivers/gpu/drm/i915/gem/i915_gem_context.c index 7720b8c22c81..5c07e6abf16a 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_context.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c @@ -230,7 +230,8 @@ static void intel_context_set_gem(struct intel_context *ce, ce->timeline = intel_timeline_get(ctx->timeline); if (ctx->sched.priority >= I915_PRIORITY_NORMAL && - intel_engine_has_timeslices(ce->engine)) + intel_engine_has_timeslices(ce->engine) && + intel_engine_has_semaphores(ce->engine)) __set_bit(CONTEXT_USE_SEMAPHORES, &ce->flags); intel_context_set_watchdog_us(ce, ctx->watchdog.timeout_us); @@ -1938,7 +1939,8 @@ static int __apply_priority(struct intel_context *ce, void *arg) if (!intel_engine_has_timeslices(ce->engine)) return 0; - if (ctx->sched.priority >= I915_PRIORITY_NORMAL) + if (ctx->sched.priority >= I915_PRIORITY_NORMAL && + intel_engine_has_semaphores(ce->engine)) intel_context_set_use_semaphores(ce); else intel_context_clear_use_semaphores(ce);
Semaphores are an optimization and not required for basic GuC submission to work properly. Disable until we have time to do the implementation to enable semaphores and tune them for performance. Also long direction is just to delete semaphores from the i915 so another reason to not enable these for GuC submission. v2: Reword commit message Cc: John Harrison <john.c.harrison@intel.com> Signed-off-by: Matthew Brost <matthew.brost@intel.com> --- drivers/gpu/drm/i915/gem/i915_gem_context.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)