From: John Harrison John.C.Harrison@Intel.com
Compute workloads are inherently not pre-emptible on current hardware. Thus the pre-emption timeout was disabled as a workaround to prevent unwanted resets. Instead, the hang detection was left to the heartbeat and its (longer) timeout. This is undesirable with GuC submission as the heartbeat is a full GT reset rather than a per engine reset and so is much more destructive. Instead, just bump the pre-emption timeout to a big value. Also, update the heartbeat to allow such a long pre-emption delay in the final heartbeat period.
v2: Add clamping helpers.
Signed-off-by: John Harrison John.C.Harrison@Intel.com
John Harrison (3): drm/i915/guc: Limit scheduling properties to avoid overflow drm/i915/gt: Make the heartbeat play nice with long pre-emption timeouts drm/i915: Improve long running OCL w/a for GuC submission
drivers/gpu/drm/i915/gt/intel_engine.h | 6 ++ drivers/gpu/drm/i915/gt/intel_engine_cs.c | 91 ++++++++++++++++++- .../gpu/drm/i915/gt/intel_engine_heartbeat.c | 16 ++++ drivers/gpu/drm/i915/gt/sysfs_engines.c | 25 +++-- drivers/gpu/drm/i915/gt/uc/intel_guc_fwif.h | 9 ++ 5 files changed, 134 insertions(+), 13 deletions(-)
From: John Harrison John.C.Harrison@Intel.com
GuC converts the pre-emption timeout and timeslice quantum values into clock ticks internally. That significantly reduces the point of 32bit overflow. On current platforms, worst case scenario is approximately 110 seconds. Rather than allowing the user to set higher values and then get confused by early timeouts, add limits when setting these values.
v2: Add helper functins for clamping (review feedback from Tvrtko).
Signed-off-by: John Harrison John.C.Harrison@Intel.com Reviewed-by: Daniele Ceraolo Spurio daniele.ceraolospurio@intel.com (v1) --- drivers/gpu/drm/i915/gt/intel_engine.h | 6 ++ drivers/gpu/drm/i915/gt/intel_engine_cs.c | 69 +++++++++++++++++++++ drivers/gpu/drm/i915/gt/sysfs_engines.c | 25 +++++--- drivers/gpu/drm/i915/gt/uc/intel_guc_fwif.h | 9 +++ 4 files changed, 99 insertions(+), 10 deletions(-)
diff --git a/drivers/gpu/drm/i915/gt/intel_engine.h b/drivers/gpu/drm/i915/gt/intel_engine.h index be4b1e65442f..5a9186f784c4 100644 --- a/drivers/gpu/drm/i915/gt/intel_engine.h +++ b/drivers/gpu/drm/i915/gt/intel_engine.h @@ -349,4 +349,10 @@ intel_engine_get_hung_context(struct intel_engine_cs *engine) return engine->hung_ce; }
+u64 intel_clamp_heartbeat_interval_ms(struct intel_engine_cs *engine, u64 value); +u64 intel_clamp_max_busywait_duration_ns(struct intel_engine_cs *engine, u64 value); +u64 intel_clamp_preempt_timeout_ms(struct intel_engine_cs *engine, u64 value); +u64 intel_clamp_stop_timeout_ms(struct intel_engine_cs *engine, u64 value); +u64 intel_clamp_timeslice_duration_ms(struct intel_engine_cs *engine, u64 value); + #endif /* _INTEL_RINGBUFFER_H_ */ diff --git a/drivers/gpu/drm/i915/gt/intel_engine_cs.c b/drivers/gpu/drm/i915/gt/intel_engine_cs.c index e855c801ba28..7ad9e6006656 100644 --- a/drivers/gpu/drm/i915/gt/intel_engine_cs.c +++ b/drivers/gpu/drm/i915/gt/intel_engine_cs.c @@ -399,6 +399,26 @@ static int intel_engine_setup(struct intel_gt *gt, enum intel_engine_id id, if (GRAPHICS_VER(i915) == 12 && engine->class == RENDER_CLASS) engine->props.preempt_timeout_ms = 0;
+ /* Cap properties according to any system limits */ +#define CLAMP_PROP(field) \ + do { \ + u64 clamp = intel_clamp_##field(engine, engine->props.field); \ + if (clamp != engine->props.field) { \ + drm_notice(&engine->i915->drm, \ + "Warning, clamping %s to %lld to prevent overflow\n", \ + #field, clamp); \ + engine->props.field = clamp; \ + } \ + } while (0) + + CLAMP_PROP(heartbeat_interval_ms); + CLAMP_PROP(max_busywait_duration_ns); + CLAMP_PROP(preempt_timeout_ms); + CLAMP_PROP(stop_timeout_ms); + CLAMP_PROP(timeslice_duration_ms); + +#undef CLAMP_PROP + engine->defaults = engine->props; /* never to change again */
engine->context_size = intel_engine_context_size(gt, engine->class); @@ -421,6 +441,55 @@ static int intel_engine_setup(struct intel_gt *gt, enum intel_engine_id id, return 0; }
+u64 intel_clamp_heartbeat_interval_ms(struct intel_engine_cs *engine, u64 value) +{ + value = min_t(u64, value, jiffies_to_msecs(MAX_SCHEDULE_TIMEOUT)); + + return value; +} + +u64 intel_clamp_max_busywait_duration_ns(struct intel_engine_cs *engine, u64 value) +{ + value = min(value, jiffies_to_nsecs(2)); + + return value; +} + +u64 intel_clamp_preempt_timeout_ms(struct intel_engine_cs *engine, u64 value) +{ + /* + * NB: The GuC API only supports 32bit values. However, the limit is further + * reduced due to internal calculations which would otherwise overflow. + */ + if (intel_guc_submission_is_wanted(&engine->gt->uc.guc)) + value = min_t(u64, value, GUC_POLICY_MAX_PREEMPT_TIMEOUT_MS); + + value = min_t(u64, value, jiffies_to_msecs(MAX_SCHEDULE_TIMEOUT)); + + return value; +} + +u64 intel_clamp_stop_timeout_ms(struct intel_engine_cs *engine, u64 value) +{ + value = min_t(u64, value, jiffies_to_msecs(MAX_SCHEDULE_TIMEOUT)); + + return value; +} + +u64 intel_clamp_timeslice_duration_ms(struct intel_engine_cs *engine, u64 value) +{ + /* + * NB: The GuC API only supports 32bit values. However, the limit is further + * reduced due to internal calculations which would otherwise overflow. + */ + if (intel_guc_submission_is_wanted(&engine->gt->uc.guc)) + value = min_t(u64, value, GUC_POLICY_MAX_EXEC_QUANTUM_MS); + + value = min_t(u64, value, jiffies_to_msecs(MAX_SCHEDULE_TIMEOUT)); + + return value; +} + static void __setup_engine_capabilities(struct intel_engine_cs *engine) { struct drm_i915_private *i915 = engine->i915; diff --git a/drivers/gpu/drm/i915/gt/sysfs_engines.c b/drivers/gpu/drm/i915/gt/sysfs_engines.c index 967031056202..f2d9858d827c 100644 --- a/drivers/gpu/drm/i915/gt/sysfs_engines.c +++ b/drivers/gpu/drm/i915/gt/sysfs_engines.c @@ -144,7 +144,7 @@ max_spin_store(struct kobject *kobj, struct kobj_attribute *attr, const char *buf, size_t count) { struct intel_engine_cs *engine = kobj_to_engine(kobj); - unsigned long long duration; + unsigned long long duration, clamped; int err;
/* @@ -168,7 +168,8 @@ max_spin_store(struct kobject *kobj, struct kobj_attribute *attr, if (err) return err;
- if (duration > jiffies_to_nsecs(2)) + clamped = intel_clamp_max_busywait_duration_ns(engine, duration); + if (duration != clamped) return -EINVAL;
WRITE_ONCE(engine->props.max_busywait_duration_ns, duration); @@ -203,7 +204,7 @@ timeslice_store(struct kobject *kobj, struct kobj_attribute *attr, const char *buf, size_t count) { struct intel_engine_cs *engine = kobj_to_engine(kobj); - unsigned long long duration; + unsigned long long duration, clamped; int err;
/* @@ -218,7 +219,8 @@ timeslice_store(struct kobject *kobj, struct kobj_attribute *attr, if (err) return err;
- if (duration > jiffies_to_msecs(MAX_SCHEDULE_TIMEOUT)) + clamped = intel_clamp_timeslice_duration_ms(engine, duration); + if (duration != clamped) return -EINVAL;
WRITE_ONCE(engine->props.timeslice_duration_ms, duration); @@ -256,7 +258,7 @@ stop_store(struct kobject *kobj, struct kobj_attribute *attr, const char *buf, size_t count) { struct intel_engine_cs *engine = kobj_to_engine(kobj); - unsigned long long duration; + unsigned long long duration, clamped; int err;
/* @@ -272,7 +274,8 @@ stop_store(struct kobject *kobj, struct kobj_attribute *attr, if (err) return err;
- if (duration > jiffies_to_msecs(MAX_SCHEDULE_TIMEOUT)) + clamped = intel_clamp_stop_timeout_ms(engine, duration); + if (duration != clamped) return -EINVAL;
WRITE_ONCE(engine->props.stop_timeout_ms, duration); @@ -306,7 +309,7 @@ preempt_timeout_store(struct kobject *kobj, struct kobj_attribute *attr, const char *buf, size_t count) { struct intel_engine_cs *engine = kobj_to_engine(kobj); - unsigned long long timeout; + unsigned long long timeout, clamped; int err;
/* @@ -322,7 +325,8 @@ preempt_timeout_store(struct kobject *kobj, struct kobj_attribute *attr, if (err) return err;
- if (timeout > jiffies_to_msecs(MAX_SCHEDULE_TIMEOUT)) + clamped = intel_clamp_preempt_timeout_ms(engine, timeout); + if (timeout != clamped) return -EINVAL;
WRITE_ONCE(engine->props.preempt_timeout_ms, timeout); @@ -362,7 +366,7 @@ heartbeat_store(struct kobject *kobj, struct kobj_attribute *attr, const char *buf, size_t count) { struct intel_engine_cs *engine = kobj_to_engine(kobj); - unsigned long long delay; + unsigned long long delay, clamped; int err;
/* @@ -379,7 +383,8 @@ heartbeat_store(struct kobject *kobj, struct kobj_attribute *attr, if (err) return err;
- if (delay >= jiffies_to_msecs(MAX_SCHEDULE_TIMEOUT)) + clamped = intel_clamp_heartbeat_interval_ms(engine, delay); + if (delay != clamped) return -EINVAL;
err = intel_engine_set_heartbeat(engine, delay); diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_fwif.h b/drivers/gpu/drm/i915/gt/uc/intel_guc_fwif.h index 6a4612a852e2..ad131092f8df 100644 --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_fwif.h +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_fwif.h @@ -248,6 +248,15 @@ struct guc_lrc_desc {
#define GLOBAL_POLICY_DEFAULT_DPC_PROMOTE_TIME_US 500000
+/* + * GuC converts the timeout to clock ticks internally. Different platforms have + * different GuC clocks. Thus, the maximum value before overflow is platform + * dependent. Current worst case scenario is about 110s. So, limit to 100s to be + * safe. + */ +#define GUC_POLICY_MAX_EXEC_QUANTUM_MS (100 * 1000) +#define GUC_POLICY_MAX_PREEMPT_TIMEOUT_MS (100 * 1000) + struct guc_policies { u32 submission_queue_depth[GUC_MAX_ENGINE_CLASSES]; /* In micro seconds. How much time to allow before DPC processing is
On 25/02/2022 20:41, John.C.Harrison@Intel.com wrote:
From: John Harrison John.C.Harrison@Intel.com
GuC converts the pre-emption timeout and timeslice quantum values into clock ticks internally. That significantly reduces the point of 32bit overflow. On current platforms, worst case scenario is approximately 110 seconds. Rather than allowing the user to set higher values and then get confused by early timeouts, add limits when setting these values.
v2: Add helper functins for clamping (review feedback from Tvrtko).
Signed-off-by: John Harrison John.C.Harrison@Intel.com Reviewed-by: Daniele Ceraolo Spurio daniele.ceraolospurio@intel.com (v1)
drivers/gpu/drm/i915/gt/intel_engine.h | 6 ++ drivers/gpu/drm/i915/gt/intel_engine_cs.c | 69 +++++++++++++++++++++ drivers/gpu/drm/i915/gt/sysfs_engines.c | 25 +++++--- drivers/gpu/drm/i915/gt/uc/intel_guc_fwif.h | 9 +++ 4 files changed, 99 insertions(+), 10 deletions(-)
diff --git a/drivers/gpu/drm/i915/gt/intel_engine.h b/drivers/gpu/drm/i915/gt/intel_engine.h index be4b1e65442f..5a9186f784c4 100644 --- a/drivers/gpu/drm/i915/gt/intel_engine.h +++ b/drivers/gpu/drm/i915/gt/intel_engine.h @@ -349,4 +349,10 @@ intel_engine_get_hung_context(struct intel_engine_cs *engine) return engine->hung_ce; }
+u64 intel_clamp_heartbeat_interval_ms(struct intel_engine_cs *engine, u64 value); +u64 intel_clamp_max_busywait_duration_ns(struct intel_engine_cs *engine, u64 value); +u64 intel_clamp_preempt_timeout_ms(struct intel_engine_cs *engine, u64 value); +u64 intel_clamp_stop_timeout_ms(struct intel_engine_cs *engine, u64 value); +u64 intel_clamp_timeslice_duration_ms(struct intel_engine_cs *engine, u64 value);
- #endif /* _INTEL_RINGBUFFER_H_ */
diff --git a/drivers/gpu/drm/i915/gt/intel_engine_cs.c b/drivers/gpu/drm/i915/gt/intel_engine_cs.c index e855c801ba28..7ad9e6006656 100644 --- a/drivers/gpu/drm/i915/gt/intel_engine_cs.c +++ b/drivers/gpu/drm/i915/gt/intel_engine_cs.c @@ -399,6 +399,26 @@ static int intel_engine_setup(struct intel_gt *gt, enum intel_engine_id id, if (GRAPHICS_VER(i915) == 12 && engine->class == RENDER_CLASS) engine->props.preempt_timeout_ms = 0;
- /* Cap properties according to any system limits */
+#define CLAMP_PROP(field) \
- do { \
u64 clamp = intel_clamp_##field(engine, engine->props.field); \if (clamp != engine->props.field) { \drm_notice(&engine->i915->drm, \"Warning, clamping %s to %lld to prevent overflow\n", \#field, clamp); \engine->props.field = clamp; \} \- } while (0)
- CLAMP_PROP(heartbeat_interval_ms);
- CLAMP_PROP(max_busywait_duration_ns);
- CLAMP_PROP(preempt_timeout_ms);
- CLAMP_PROP(stop_timeout_ms);
- CLAMP_PROP(timeslice_duration_ms);
+#undef CLAMP_PROP
engine->defaults = engine->props; /* never to change again */
engine->context_size = intel_engine_context_size(gt, engine->class);
@@ -421,6 +441,55 @@ static int intel_engine_setup(struct intel_gt *gt, enum intel_engine_id id, return 0; }
+u64 intel_clamp_heartbeat_interval_ms(struct intel_engine_cs *engine, u64 value) +{
- value = min_t(u64, value, jiffies_to_msecs(MAX_SCHEDULE_TIMEOUT));
- return value;
+}
+u64 intel_clamp_max_busywait_duration_ns(struct intel_engine_cs *engine, u64 value) +{
- value = min(value, jiffies_to_nsecs(2));
- return value;
+}
+u64 intel_clamp_preempt_timeout_ms(struct intel_engine_cs *engine, u64 value) +{
- /*
* NB: The GuC API only supports 32bit values. However, the limit is further* reduced due to internal calculations which would otherwise overflow.*/- if (intel_guc_submission_is_wanted(&engine->gt->uc.guc))
value = min_t(u64, value, GUC_POLICY_MAX_PREEMPT_TIMEOUT_MS);- value = min_t(u64, value, jiffies_to_msecs(MAX_SCHEDULE_TIMEOUT));
- return value;
+}
+u64 intel_clamp_stop_timeout_ms(struct intel_engine_cs *engine, u64 value) +{
- value = min_t(u64, value, jiffies_to_msecs(MAX_SCHEDULE_TIMEOUT));
- return value;
+}
+u64 intel_clamp_timeslice_duration_ms(struct intel_engine_cs *engine, u64 value) +{
- /*
* NB: The GuC API only supports 32bit values. However, the limit is further* reduced due to internal calculations which would otherwise overflow.*/- if (intel_guc_submission_is_wanted(&engine->gt->uc.guc))
value = min_t(u64, value, GUC_POLICY_MAX_EXEC_QUANTUM_MS);- value = min_t(u64, value, jiffies_to_msecs(MAX_SCHEDULE_TIMEOUT));
- return value;
+}
- static void __setup_engine_capabilities(struct intel_engine_cs *engine) { struct drm_i915_private *i915 = engine->i915;
diff --git a/drivers/gpu/drm/i915/gt/sysfs_engines.c b/drivers/gpu/drm/i915/gt/sysfs_engines.c index 967031056202..f2d9858d827c 100644 --- a/drivers/gpu/drm/i915/gt/sysfs_engines.c +++ b/drivers/gpu/drm/i915/gt/sysfs_engines.c @@ -144,7 +144,7 @@ max_spin_store(struct kobject *kobj, struct kobj_attribute *attr, const char *buf, size_t count) { struct intel_engine_cs *engine = kobj_to_engine(kobj);
- unsigned long long duration;
unsigned long long duration, clamped; int err;
/*
@@ -168,7 +168,8 @@ max_spin_store(struct kobject *kobj, struct kobj_attribute *attr, if (err) return err;
- if (duration > jiffies_to_nsecs(2))
clamped = intel_clamp_max_busywait_duration_ns(engine, duration);
if (duration != clamped) return -EINVAL;
WRITE_ONCE(engine->props.max_busywait_duration_ns, duration);
@@ -203,7 +204,7 @@ timeslice_store(struct kobject *kobj, struct kobj_attribute *attr, const char *buf, size_t count) { struct intel_engine_cs *engine = kobj_to_engine(kobj);
- unsigned long long duration;
unsigned long long duration, clamped; int err;
/*
@@ -218,7 +219,8 @@ timeslice_store(struct kobject *kobj, struct kobj_attribute *attr, if (err) return err;
- if (duration > jiffies_to_msecs(MAX_SCHEDULE_TIMEOUT))
clamped = intel_clamp_timeslice_duration_ms(engine, duration);
if (duration != clamped) return -EINVAL;
WRITE_ONCE(engine->props.timeslice_duration_ms, duration);
@@ -256,7 +258,7 @@ stop_store(struct kobject *kobj, struct kobj_attribute *attr, const char *buf, size_t count) { struct intel_engine_cs *engine = kobj_to_engine(kobj);
- unsigned long long duration;
unsigned long long duration, clamped; int err;
/*
@@ -272,7 +274,8 @@ stop_store(struct kobject *kobj, struct kobj_attribute *attr, if (err) return err;
- if (duration > jiffies_to_msecs(MAX_SCHEDULE_TIMEOUT))
clamped = intel_clamp_stop_timeout_ms(engine, duration);
if (duration != clamped) return -EINVAL;
WRITE_ONCE(engine->props.stop_timeout_ms, duration);
@@ -306,7 +309,7 @@ preempt_timeout_store(struct kobject *kobj, struct kobj_attribute *attr, const char *buf, size_t count) { struct intel_engine_cs *engine = kobj_to_engine(kobj);
- unsigned long long timeout;
unsigned long long timeout, clamped; int err;
/*
@@ -322,7 +325,8 @@ preempt_timeout_store(struct kobject *kobj, struct kobj_attribute *attr, if (err) return err;
- if (timeout > jiffies_to_msecs(MAX_SCHEDULE_TIMEOUT))
clamped = intel_clamp_preempt_timeout_ms(engine, timeout);
if (timeout != clamped) return -EINVAL;
WRITE_ONCE(engine->props.preempt_timeout_ms, timeout);
@@ -362,7 +366,7 @@ heartbeat_store(struct kobject *kobj, struct kobj_attribute *attr, const char *buf, size_t count) { struct intel_engine_cs *engine = kobj_to_engine(kobj);
- unsigned long long delay;
unsigned long long delay, clamped; int err;
/*
@@ -379,7 +383,8 @@ heartbeat_store(struct kobject *kobj, struct kobj_attribute *attr, if (err) return err;
- if (delay >= jiffies_to_msecs(MAX_SCHEDULE_TIMEOUT))
clamped = intel_clamp_heartbeat_interval_ms(engine, delay);
if (delay != clamped) return -EINVAL;
err = intel_engine_set_heartbeat(engine, delay);
diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_fwif.h b/drivers/gpu/drm/i915/gt/uc/intel_guc_fwif.h index 6a4612a852e2..ad131092f8df 100644 --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_fwif.h +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_fwif.h @@ -248,6 +248,15 @@ struct guc_lrc_desc {
#define GLOBAL_POLICY_DEFAULT_DPC_PROMOTE_TIME_US 500000
+/*
- GuC converts the timeout to clock ticks internally. Different platforms have
- different GuC clocks. Thus, the maximum value before overflow is platform
- dependent. Current worst case scenario is about 110s. So, limit to 100s to be
- safe.
- */
+#define GUC_POLICY_MAX_EXEC_QUANTUM_MS (100 * 1000) +#define GUC_POLICY_MAX_PREEMPT_TIMEOUT_MS (100 * 1000)
- struct guc_policies { u32 submission_queue_depth[GUC_MAX_ENGINE_CLASSES]; /* In micro seconds. How much time to allow before DPC processing is
LGTM. Pretty please:
diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c index b3a429a92c0d..8208164c25e7 100644 --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c @@ -2218,13 +2218,24 @@ static inline u32 get_children_join_value(struct intel_context *ce, static void guc_context_policy_init(struct intel_engine_cs *engine, struct guc_lrc_desc *desc) { + struct drm_device *drm = &engine->i915->drm; + desc->policy_flags = 0;
if (engine->flags & I915_ENGINE_WANT_FORCED_PREEMPTION) desc->policy_flags |= CONTEXT_POLICY_FLAG_PREEMPT_TO_IDLE;
/* NB: For both of these, zero means disabled. */ + if (overflows_type(engine->props.timeslice_duration_ms * 1000, + desc->execution_quantum)) + drm_warn_once(drm, "GuC interface cannot support %lums timeslice!\n", + engine->props.timeslice_duration_ms); desc->execution_quantum = engine->props.timeslice_duration_ms * 1000; + + if (overflows_type(engine->props.preempt_timeout_ms * 1000, + desc->preemption_timeout)) + drm_warn_once(drm, "GuC interface cannot support %lums preemption timeout!\n", + engine->props.preempt_timeout_ms); desc->preemption_timeout = engine->props.preempt_timeout_ms * 1000; }
With that:
Reviewed-by: Tvrtko Ursulin tvrtko.ursulin@intel.com
Any idea what happened with the CI run? It's full of odd failures.
Regards,
Tvrtko
On 3/2/2022 01:49, Tvrtko Ursulin wrote:
On 25/02/2022 20:41, John.C.Harrison@Intel.com wrote:
From: John Harrison John.C.Harrison@Intel.com
GuC converts the pre-emption timeout and timeslice quantum values into clock ticks internally. That significantly reduces the point of 32bit overflow. On current platforms, worst case scenario is approximately 110 seconds. Rather than allowing the user to set higher values and then get confused by early timeouts, add limits when setting these values.
v2: Add helper functins for clamping (review feedback from Tvrtko).
Signed-off-by: John Harrison John.C.Harrison@Intel.com Reviewed-by: Daniele Ceraolo Spurio daniele.ceraolospurio@intel.com (v1)
drivers/gpu/drm/i915/gt/intel_engine.h | 6 ++ drivers/gpu/drm/i915/gt/intel_engine_cs.c | 69 +++++++++++++++++++++ drivers/gpu/drm/i915/gt/sysfs_engines.c | 25 +++++--- drivers/gpu/drm/i915/gt/uc/intel_guc_fwif.h | 9 +++ 4 files changed, 99 insertions(+), 10 deletions(-)
diff --git a/drivers/gpu/drm/i915/gt/intel_engine.h b/drivers/gpu/drm/i915/gt/intel_engine.h index be4b1e65442f..5a9186f784c4 100644 --- a/drivers/gpu/drm/i915/gt/intel_engine.h +++ b/drivers/gpu/drm/i915/gt/intel_engine.h @@ -349,4 +349,10 @@ intel_engine_get_hung_context(struct intel_engine_cs *engine) return engine->hung_ce; } +u64 intel_clamp_heartbeat_interval_ms(struct intel_engine_cs *engine, u64 value); +u64 intel_clamp_max_busywait_duration_ns(struct intel_engine_cs *engine, u64 value); +u64 intel_clamp_preempt_timeout_ms(struct intel_engine_cs *engine, u64 value); +u64 intel_clamp_stop_timeout_ms(struct intel_engine_cs *engine, u64 value); +u64 intel_clamp_timeslice_duration_ms(struct intel_engine_cs *engine, u64 value);
#endif /* _INTEL_RINGBUFFER_H_ */ diff --git a/drivers/gpu/drm/i915/gt/intel_engine_cs.c b/drivers/gpu/drm/i915/gt/intel_engine_cs.c index e855c801ba28..7ad9e6006656 100644 --- a/drivers/gpu/drm/i915/gt/intel_engine_cs.c +++ b/drivers/gpu/drm/i915/gt/intel_engine_cs.c @@ -399,6 +399,26 @@ static int intel_engine_setup(struct intel_gt *gt, enum intel_engine_id id, if (GRAPHICS_VER(i915) == 12 && engine->class == RENDER_CLASS) engine->props.preempt_timeout_ms = 0; + /* Cap properties according to any system limits */ +#define CLAMP_PROP(field) \ + do { \ + u64 clamp = intel_clamp_##field(engine, engine->props.field); \ + if (clamp != engine->props.field) { \ + drm_notice(&engine->i915->drm, \ + "Warning, clamping %s to %lld to prevent overflow\n", \ + #field, clamp); \ + engine->props.field = clamp; \ + } \ + } while (0)
+ CLAMP_PROP(heartbeat_interval_ms); + CLAMP_PROP(max_busywait_duration_ns); + CLAMP_PROP(preempt_timeout_ms); + CLAMP_PROP(stop_timeout_ms); + CLAMP_PROP(timeslice_duration_ms);
+#undef CLAMP_PROP
engine->defaults = engine->props; /* never to change again */ engine->context_size = intel_engine_context_size(gt, engine->class); @@ -421,6 +441,55 @@ static int intel_engine_setup(struct intel_gt *gt, enum intel_engine_id id, return 0; } +u64 intel_clamp_heartbeat_interval_ms(struct intel_engine_cs *engine, u64 value) +{ + value = min_t(u64, value, jiffies_to_msecs(MAX_SCHEDULE_TIMEOUT));
+ return value; +}
+u64 intel_clamp_max_busywait_duration_ns(struct intel_engine_cs *engine, u64 value) +{ + value = min(value, jiffies_to_nsecs(2));
+ return value; +}
+u64 intel_clamp_preempt_timeout_ms(struct intel_engine_cs *engine, u64 value) +{ + /* + * NB: The GuC API only supports 32bit values. However, the limit is further + * reduced due to internal calculations which would otherwise overflow. + */ + if (intel_guc_submission_is_wanted(&engine->gt->uc.guc)) + value = min_t(u64, value, GUC_POLICY_MAX_PREEMPT_TIMEOUT_MS);
+ value = min_t(u64, value, jiffies_to_msecs(MAX_SCHEDULE_TIMEOUT));
+ return value; +}
+u64 intel_clamp_stop_timeout_ms(struct intel_engine_cs *engine, u64 value) +{ + value = min_t(u64, value, jiffies_to_msecs(MAX_SCHEDULE_TIMEOUT));
+ return value; +}
+u64 intel_clamp_timeslice_duration_ms(struct intel_engine_cs *engine, u64 value) +{ + /* + * NB: The GuC API only supports 32bit values. However, the limit is further + * reduced due to internal calculations which would otherwise overflow. + */ + if (intel_guc_submission_is_wanted(&engine->gt->uc.guc)) + value = min_t(u64, value, GUC_POLICY_MAX_EXEC_QUANTUM_MS);
+ value = min_t(u64, value, jiffies_to_msecs(MAX_SCHEDULE_TIMEOUT));
+ return value; +}
static void __setup_engine_capabilities(struct intel_engine_cs *engine) { struct drm_i915_private *i915 = engine->i915; diff --git a/drivers/gpu/drm/i915/gt/sysfs_engines.c b/drivers/gpu/drm/i915/gt/sysfs_engines.c index 967031056202..f2d9858d827c 100644 --- a/drivers/gpu/drm/i915/gt/sysfs_engines.c +++ b/drivers/gpu/drm/i915/gt/sysfs_engines.c @@ -144,7 +144,7 @@ max_spin_store(struct kobject *kobj, struct kobj_attribute *attr, const char *buf, size_t count) { struct intel_engine_cs *engine = kobj_to_engine(kobj); - unsigned long long duration; + unsigned long long duration, clamped; int err; /* @@ -168,7 +168,8 @@ max_spin_store(struct kobject *kobj, struct kobj_attribute *attr, if (err) return err; - if (duration > jiffies_to_nsecs(2)) + clamped = intel_clamp_max_busywait_duration_ns(engine, duration); + if (duration != clamped) return -EINVAL; WRITE_ONCE(engine->props.max_busywait_duration_ns, duration); @@ -203,7 +204,7 @@ timeslice_store(struct kobject *kobj, struct kobj_attribute *attr, const char *buf, size_t count) { struct intel_engine_cs *engine = kobj_to_engine(kobj); - unsigned long long duration; + unsigned long long duration, clamped; int err; /* @@ -218,7 +219,8 @@ timeslice_store(struct kobject *kobj, struct kobj_attribute *attr, if (err) return err; - if (duration > jiffies_to_msecs(MAX_SCHEDULE_TIMEOUT)) + clamped = intel_clamp_timeslice_duration_ms(engine, duration); + if (duration != clamped) return -EINVAL; WRITE_ONCE(engine->props.timeslice_duration_ms, duration); @@ -256,7 +258,7 @@ stop_store(struct kobject *kobj, struct kobj_attribute *attr, const char *buf, size_t count) { struct intel_engine_cs *engine = kobj_to_engine(kobj); - unsigned long long duration; + unsigned long long duration, clamped; int err; /* @@ -272,7 +274,8 @@ stop_store(struct kobject *kobj, struct kobj_attribute *attr, if (err) return err; - if (duration > jiffies_to_msecs(MAX_SCHEDULE_TIMEOUT)) + clamped = intel_clamp_stop_timeout_ms(engine, duration); + if (duration != clamped) return -EINVAL; WRITE_ONCE(engine->props.stop_timeout_ms, duration); @@ -306,7 +309,7 @@ preempt_timeout_store(struct kobject *kobj, struct kobj_attribute *attr, const char *buf, size_t count) { struct intel_engine_cs *engine = kobj_to_engine(kobj); - unsigned long long timeout; + unsigned long long timeout, clamped; int err; /* @@ -322,7 +325,8 @@ preempt_timeout_store(struct kobject *kobj, struct kobj_attribute *attr, if (err) return err; - if (timeout > jiffies_to_msecs(MAX_SCHEDULE_TIMEOUT)) + clamped = intel_clamp_preempt_timeout_ms(engine, timeout); + if (timeout != clamped) return -EINVAL; WRITE_ONCE(engine->props.preempt_timeout_ms, timeout); @@ -362,7 +366,7 @@ heartbeat_store(struct kobject *kobj, struct kobj_attribute *attr, const char *buf, size_t count) { struct intel_engine_cs *engine = kobj_to_engine(kobj); - unsigned long long delay; + unsigned long long delay, clamped; int err; /* @@ -379,7 +383,8 @@ heartbeat_store(struct kobject *kobj, struct kobj_attribute *attr, if (err) return err; - if (delay >= jiffies_to_msecs(MAX_SCHEDULE_TIMEOUT)) + clamped = intel_clamp_heartbeat_interval_ms(engine, delay); + if (delay != clamped) return -EINVAL; err = intel_engine_set_heartbeat(engine, delay); diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_fwif.h b/drivers/gpu/drm/i915/gt/uc/intel_guc_fwif.h index 6a4612a852e2..ad131092f8df 100644 --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_fwif.h +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_fwif.h @@ -248,6 +248,15 @@ struct guc_lrc_desc { #define GLOBAL_POLICY_DEFAULT_DPC_PROMOTE_TIME_US 500000 +/*
- GuC converts the timeout to clock ticks internally. Different
platforms have
- different GuC clocks. Thus, the maximum value before overflow is
platform
- dependent. Current worst case scenario is about 110s. So, limit
to 100s to be
- safe.
- */
+#define GUC_POLICY_MAX_EXEC_QUANTUM_MS (100 * 1000) +#define GUC_POLICY_MAX_PREEMPT_TIMEOUT_MS (100 * 1000)
struct guc_policies { u32 submission_queue_depth[GUC_MAX_ENGINE_CLASSES]; /* In micro seconds. How much time to allow before DPC processing is
LGTM. Pretty please:
diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c index b3a429a92c0d..8208164c25e7 100644 --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c @@ -2218,13 +2218,24 @@ static inline u32 get_children_join_value(struct intel_context *ce, static void guc_context_policy_init(struct intel_engine_cs *engine, struct guc_lrc_desc *desc) { + struct drm_device *drm = &engine->i915->drm;
desc->policy_flags = 0;
if (engine->flags & I915_ENGINE_WANT_FORCED_PREEMPTION) desc->policy_flags |= CONTEXT_POLICY_FLAG_PREEMPT_TO_IDLE;
/* NB: For both of these, zero means disabled. */ + if (overflows_type(engine->props.timeslice_duration_ms * 1000, + desc->execution_quantum)) + drm_warn_once(drm, "GuC interface cannot support %lums timeslice!\n",
- engine->props.timeslice_duration_ms);
desc->execution_quantum = engine->props.timeslice_duration_ms
- 1000;
+ if (overflows_type(engine->props.preempt_timeout_ms * 1000, + desc->preemption_timeout)) + drm_warn_once(drm, "GuC interface cannot support %lums preemption timeout!\n",
- engine->props.preempt_timeout_ms);
desc->preemption_timeout = engine->props.preempt_timeout_ms * 1000; }
As per comments in other thread, this is redundant code and is too late in the chain to do anything. If such a check is present then should be a BUG not a drm_warn. The whole point of the helper function is to consolidate all limits in one place at the point where it is still possible to correct for problems.
With that:
Reviewed-by: Tvrtko Ursulin tvrtko.ursulin@intel.com
Any idea what happened with the CI run? It's full of odd failures.
Not sure where 'rev3' came from, it's the 'rev2' code and I don't recall hitting the 'retest' button. Either way, that version just hit a merge conflict and didn't build. The previous two revs seemed to be hitting 'failed to reset' problems in an execlist selftest on execlist only platforms. I'm not seeing how that could be related. The changes should only kick in on Gen12 platforms and/or with GuC submission but the failures are all on earlier platforms. I'm planning to grab a SKL or something to test on to make sure, I just haven't had the time to do so yet.
John.
Regards,
Tvrtko
On 02/03/2022 18:22, John Harrison wrote:
On 3/2/2022 01:49, Tvrtko Ursulin wrote:
On 25/02/2022 20:41, John.C.Harrison@Intel.com wrote:
From: John Harrison John.C.Harrison@Intel.com
GuC converts the pre-emption timeout and timeslice quantum values into clock ticks internally. That significantly reduces the point of 32bit overflow. On current platforms, worst case scenario is approximately 110 seconds. Rather than allowing the user to set higher values and then get confused by early timeouts, add limits when setting these values.
v2: Add helper functins for clamping (review feedback from Tvrtko).
Signed-off-by: John Harrison John.C.Harrison@Intel.com Reviewed-by: Daniele Ceraolo Spurio daniele.ceraolospurio@intel.com (v1)
drivers/gpu/drm/i915/gt/intel_engine.h | 6 ++ drivers/gpu/drm/i915/gt/intel_engine_cs.c | 69 +++++++++++++++++++++ drivers/gpu/drm/i915/gt/sysfs_engines.c | 25 +++++--- drivers/gpu/drm/i915/gt/uc/intel_guc_fwif.h | 9 +++ 4 files changed, 99 insertions(+), 10 deletions(-)
diff --git a/drivers/gpu/drm/i915/gt/intel_engine.h b/drivers/gpu/drm/i915/gt/intel_engine.h index be4b1e65442f..5a9186f784c4 100644 --- a/drivers/gpu/drm/i915/gt/intel_engine.h +++ b/drivers/gpu/drm/i915/gt/intel_engine.h @@ -349,4 +349,10 @@ intel_engine_get_hung_context(struct intel_engine_cs *engine) return engine->hung_ce; } +u64 intel_clamp_heartbeat_interval_ms(struct intel_engine_cs *engine, u64 value); +u64 intel_clamp_max_busywait_duration_ns(struct intel_engine_cs *engine, u64 value); +u64 intel_clamp_preempt_timeout_ms(struct intel_engine_cs *engine, u64 value); +u64 intel_clamp_stop_timeout_ms(struct intel_engine_cs *engine, u64 value); +u64 intel_clamp_timeslice_duration_ms(struct intel_engine_cs *engine, u64 value);
#endif /* _INTEL_RINGBUFFER_H_ */ diff --git a/drivers/gpu/drm/i915/gt/intel_engine_cs.c b/drivers/gpu/drm/i915/gt/intel_engine_cs.c index e855c801ba28..7ad9e6006656 100644 --- a/drivers/gpu/drm/i915/gt/intel_engine_cs.c +++ b/drivers/gpu/drm/i915/gt/intel_engine_cs.c @@ -399,6 +399,26 @@ static int intel_engine_setup(struct intel_gt *gt, enum intel_engine_id id, if (GRAPHICS_VER(i915) == 12 && engine->class == RENDER_CLASS) engine->props.preempt_timeout_ms = 0; + /* Cap properties according to any system limits */ +#define CLAMP_PROP(field) \ + do { \ + u64 clamp = intel_clamp_##field(engine, engine->props.field); \ + if (clamp != engine->props.field) { \ + drm_notice(&engine->i915->drm, \ + "Warning, clamping %s to %lld to prevent overflow\n", \ + #field, clamp); \ + engine->props.field = clamp; \ + } \ + } while (0)
+ CLAMP_PROP(heartbeat_interval_ms); + CLAMP_PROP(max_busywait_duration_ns); + CLAMP_PROP(preempt_timeout_ms); + CLAMP_PROP(stop_timeout_ms); + CLAMP_PROP(timeslice_duration_ms);
+#undef CLAMP_PROP
engine->defaults = engine->props; /* never to change again */ engine->context_size = intel_engine_context_size(gt, engine->class); @@ -421,6 +441,55 @@ static int intel_engine_setup(struct intel_gt *gt, enum intel_engine_id id, return 0; } +u64 intel_clamp_heartbeat_interval_ms(struct intel_engine_cs *engine, u64 value) +{ + value = min_t(u64, value, jiffies_to_msecs(MAX_SCHEDULE_TIMEOUT));
+ return value; +}
+u64 intel_clamp_max_busywait_duration_ns(struct intel_engine_cs *engine, u64 value) +{ + value = min(value, jiffies_to_nsecs(2));
+ return value; +}
+u64 intel_clamp_preempt_timeout_ms(struct intel_engine_cs *engine, u64 value) +{ + /* + * NB: The GuC API only supports 32bit values. However, the limit is further + * reduced due to internal calculations which would otherwise overflow. + */ + if (intel_guc_submission_is_wanted(&engine->gt->uc.guc)) + value = min_t(u64, value, GUC_POLICY_MAX_PREEMPT_TIMEOUT_MS);
+ value = min_t(u64, value, jiffies_to_msecs(MAX_SCHEDULE_TIMEOUT));
+ return value; +}
+u64 intel_clamp_stop_timeout_ms(struct intel_engine_cs *engine, u64 value) +{ + value = min_t(u64, value, jiffies_to_msecs(MAX_SCHEDULE_TIMEOUT));
+ return value; +}
+u64 intel_clamp_timeslice_duration_ms(struct intel_engine_cs *engine, u64 value) +{ + /* + * NB: The GuC API only supports 32bit values. However, the limit is further + * reduced due to internal calculations which would otherwise overflow. + */ + if (intel_guc_submission_is_wanted(&engine->gt->uc.guc)) + value = min_t(u64, value, GUC_POLICY_MAX_EXEC_QUANTUM_MS);
+ value = min_t(u64, value, jiffies_to_msecs(MAX_SCHEDULE_TIMEOUT));
+ return value; +}
static void __setup_engine_capabilities(struct intel_engine_cs *engine) { struct drm_i915_private *i915 = engine->i915; diff --git a/drivers/gpu/drm/i915/gt/sysfs_engines.c b/drivers/gpu/drm/i915/gt/sysfs_engines.c index 967031056202..f2d9858d827c 100644 --- a/drivers/gpu/drm/i915/gt/sysfs_engines.c +++ b/drivers/gpu/drm/i915/gt/sysfs_engines.c @@ -144,7 +144,7 @@ max_spin_store(struct kobject *kobj, struct kobj_attribute *attr, const char *buf, size_t count) { struct intel_engine_cs *engine = kobj_to_engine(kobj); - unsigned long long duration; + unsigned long long duration, clamped; int err; /* @@ -168,7 +168,8 @@ max_spin_store(struct kobject *kobj, struct kobj_attribute *attr, if (err) return err; - if (duration > jiffies_to_nsecs(2)) + clamped = intel_clamp_max_busywait_duration_ns(engine, duration); + if (duration != clamped) return -EINVAL; WRITE_ONCE(engine->props.max_busywait_duration_ns, duration); @@ -203,7 +204,7 @@ timeslice_store(struct kobject *kobj, struct kobj_attribute *attr, const char *buf, size_t count) { struct intel_engine_cs *engine = kobj_to_engine(kobj); - unsigned long long duration; + unsigned long long duration, clamped; int err; /* @@ -218,7 +219,8 @@ timeslice_store(struct kobject *kobj, struct kobj_attribute *attr, if (err) return err; - if (duration > jiffies_to_msecs(MAX_SCHEDULE_TIMEOUT)) + clamped = intel_clamp_timeslice_duration_ms(engine, duration); + if (duration != clamped) return -EINVAL; WRITE_ONCE(engine->props.timeslice_duration_ms, duration); @@ -256,7 +258,7 @@ stop_store(struct kobject *kobj, struct kobj_attribute *attr, const char *buf, size_t count) { struct intel_engine_cs *engine = kobj_to_engine(kobj); - unsigned long long duration; + unsigned long long duration, clamped; int err; /* @@ -272,7 +274,8 @@ stop_store(struct kobject *kobj, struct kobj_attribute *attr, if (err) return err; - if (duration > jiffies_to_msecs(MAX_SCHEDULE_TIMEOUT)) + clamped = intel_clamp_stop_timeout_ms(engine, duration); + if (duration != clamped) return -EINVAL; WRITE_ONCE(engine->props.stop_timeout_ms, duration); @@ -306,7 +309,7 @@ preempt_timeout_store(struct kobject *kobj, struct kobj_attribute *attr, const char *buf, size_t count) { struct intel_engine_cs *engine = kobj_to_engine(kobj); - unsigned long long timeout; + unsigned long long timeout, clamped; int err; /* @@ -322,7 +325,8 @@ preempt_timeout_store(struct kobject *kobj, struct kobj_attribute *attr, if (err) return err; - if (timeout > jiffies_to_msecs(MAX_SCHEDULE_TIMEOUT)) + clamped = intel_clamp_preempt_timeout_ms(engine, timeout); + if (timeout != clamped) return -EINVAL; WRITE_ONCE(engine->props.preempt_timeout_ms, timeout); @@ -362,7 +366,7 @@ heartbeat_store(struct kobject *kobj, struct kobj_attribute *attr, const char *buf, size_t count) { struct intel_engine_cs *engine = kobj_to_engine(kobj); - unsigned long long delay; + unsigned long long delay, clamped; int err; /* @@ -379,7 +383,8 @@ heartbeat_store(struct kobject *kobj, struct kobj_attribute *attr, if (err) return err; - if (delay >= jiffies_to_msecs(MAX_SCHEDULE_TIMEOUT)) + clamped = intel_clamp_heartbeat_interval_ms(engine, delay); + if (delay != clamped) return -EINVAL; err = intel_engine_set_heartbeat(engine, delay); diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_fwif.h b/drivers/gpu/drm/i915/gt/uc/intel_guc_fwif.h index 6a4612a852e2..ad131092f8df 100644 --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_fwif.h +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_fwif.h @@ -248,6 +248,15 @@ struct guc_lrc_desc { #define GLOBAL_POLICY_DEFAULT_DPC_PROMOTE_TIME_US 500000 +/*
- GuC converts the timeout to clock ticks internally. Different
platforms have
- different GuC clocks. Thus, the maximum value before overflow is
platform
- dependent. Current worst case scenario is about 110s. So, limit
to 100s to be
- safe.
- */
+#define GUC_POLICY_MAX_EXEC_QUANTUM_MS (100 * 1000) +#define GUC_POLICY_MAX_PREEMPT_TIMEOUT_MS (100 * 1000)
struct guc_policies { u32 submission_queue_depth[GUC_MAX_ENGINE_CLASSES]; /* In micro seconds. How much time to allow before DPC processing is
LGTM. Pretty please:
diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c index b3a429a92c0d..8208164c25e7 100644 --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c @@ -2218,13 +2218,24 @@ static inline u32 get_children_join_value(struct intel_context *ce, static void guc_context_policy_init(struct intel_engine_cs *engine, struct guc_lrc_desc *desc) { + struct drm_device *drm = &engine->i915->drm;
desc->policy_flags = 0;
if (engine->flags & I915_ENGINE_WANT_FORCED_PREEMPTION) desc->policy_flags |= CONTEXT_POLICY_FLAG_PREEMPT_TO_IDLE;
/* NB: For both of these, zero means disabled. */ + if (overflows_type(engine->props.timeslice_duration_ms * 1000, + desc->execution_quantum)) + drm_warn_once(drm, "GuC interface cannot support %lums timeslice!\n",
- engine->props.timeslice_duration_ms);
desc->execution_quantum = engine->props.timeslice_duration_ms
- 1000;
+ if (overflows_type(engine->props.preempt_timeout_ms * 1000, + desc->preemption_timeout)) + drm_warn_once(drm, "GuC interface cannot support %lums preemption timeout!\n",
- engine->props.preempt_timeout_ms);
desc->preemption_timeout = engine->props.preempt_timeout_ms * 1000; }
As per comments in other thread, this is redundant code and is too late in the chain to do anything. If such a check is present then should be a BUG not a drm_warn. The whole point of the helper function is to consolidate all limits in one place at the point where it is still possible to correct for problems.
You could put this check in the clamp helpers. I not sure it would look amazing since it needs access to struct guc_lrc_desc, which is much lower layer, but perhaps it would be passable since some implementation knowledge (MAX_SCHEDULE_TIMEOUT) is already there. Maybe by the time you multiply by 1000 to check it start looking too ugly. Not sure. I would just stick with the above diff. Point is not whether it is too late or not, point is just to have a marker which would let us know we forgot about something, if it comes to it. Could also be a drm_WARN_ON_ONCE, no strong preference from my side.
Regards,
Tvrtko
From: John Harrison John.C.Harrison@Intel.com
Compute workloads are inherently not pre-emptible for long periods on current hardware. As a workaround for this, the pre-emption timeout for compute capable engines was disabled. This is undesirable with GuC submission as it prevents per engine reset of hung contexts. Hence the next patch will re-enable the timeout but bumped up by an order of magnitude.
However, the heartbeat might not respect that. Depending upon current activity, a pre-emption to the heartbeat pulse might not even be attempted until the last heartbeat period. Which means that only one period is granted for the pre-emption to occur. With the aforesaid bump, the pre-emption timeout could be significantly larger than this heartbeat period.
So adjust the heartbeat code to take the pre-emption timeout into account. When it reaches the final (high priority) period, it now ensures the delay before hitting reset is bigger than the pre-emption timeout.
Signed-off-by: John Harrison John.C.Harrison@Intel.com --- drivers/gpu/drm/i915/gt/intel_engine_heartbeat.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+)
diff --git a/drivers/gpu/drm/i915/gt/intel_engine_heartbeat.c b/drivers/gpu/drm/i915/gt/intel_engine_heartbeat.c index a3698f611f45..72a82a6085e0 100644 --- a/drivers/gpu/drm/i915/gt/intel_engine_heartbeat.c +++ b/drivers/gpu/drm/i915/gt/intel_engine_heartbeat.c @@ -22,9 +22,25 @@
static bool next_heartbeat(struct intel_engine_cs *engine) { + struct i915_request *rq; long delay;
delay = READ_ONCE(engine->props.heartbeat_interval_ms); + + rq = engine->heartbeat.systole; + if (rq && rq->sched.attr.priority >= I915_PRIORITY_BARRIER) { + long longer; + + /* + * The final try is at the highest priority possible. Up until now + * a pre-emption might not even have been attempted. So make sure + * this last attempt allows enough time for a pre-emption to occur. + */ + longer = READ_ONCE(engine->props.preempt_timeout_ms) * 2; + if (longer > delay) + delay = longer; + } + if (!delay) return false;
From: John Harrison John.C.Harrison@Intel.com
A workaround was added to the driver to allow OpenCL workloads to run 'forever' by disabling pre-emption on the RCS engine for Gen12. It is not totally unbound as the heartbeat will kick in eventually and cause a reset of the hung engine.
However, this does not work well in GuC submission mode. In GuC mode, the pre-emption timeout is how GuC detects hung contexts and triggers a per engine reset. Thus, disabling the timeout means also losing all per engine reset ability. A full GT reset will still occur when the heartbeat finally expires, but that is a much more destructive and undesirable mechanism.
The purpose of the workaround is actually to give OpenCL tasks longer to reach a pre-emption point after a pre-emption request has been issued. This is necessary because Gen12 does not support mid-thread pre-emption and OpenCL can have long running threads.
So, rather than disabling the timeout completely, just set it to a 'long' value.
Signed-off-by: John Harrison John.C.Harrison@Intel.com Reviewed-by: Daniele Ceraolo Spurio daniele.ceraolospurio@intel.com Acked-by: Michal Mrozek michal.mrozek@intel.com --- drivers/gpu/drm/i915/gt/intel_engine_cs.c | 22 +++++++++++++++++++--- 1 file changed, 19 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/i915/gt/intel_engine_cs.c b/drivers/gpu/drm/i915/gt/intel_engine_cs.c index 7ad9e6006656..84db5bf36285 100644 --- a/drivers/gpu/drm/i915/gt/intel_engine_cs.c +++ b/drivers/gpu/drm/i915/gt/intel_engine_cs.c @@ -395,9 +395,25 @@ static int intel_engine_setup(struct intel_gt *gt, enum intel_engine_id id, engine->props.timeslice_duration_ms = CONFIG_DRM_I915_TIMESLICE_DURATION;
- /* Override to uninterruptible for OpenCL workloads. */ - if (GRAPHICS_VER(i915) == 12 && engine->class == RENDER_CLASS) - engine->props.preempt_timeout_ms = 0; + /* + * Mid-thread pre-emption is not available in Gen12. Unfortunately, + * some OpenCL workloads run quite long threads. That means they get + * reset due to not pre-empting in a timely manner. So, bump the + * pre-emption timeout value to be much higher for compute engines. + * Using three times the heartbeat period seems long enough for a + * reasonable task to reach a pre-emption point but not so long as to + * allow genuine hangs to go unresolved. + */ + if (GRAPHICS_VER(i915) == 12 && engine->class == RENDER_CLASS) { + unsigned long triple_beat = engine->props.heartbeat_interval_ms * 3; + + if (triple_beat > engine->props.preempt_timeout_ms) { + drm_info(>->i915->drm, "Bumping pre-emption timeout from %ld to %ld on %s to allow slow compute pre-emption\n", + engine->props.preempt_timeout_ms, triple_beat, engine->name); + + engine->props.preempt_timeout_ms = triple_beat; + } + }
/* Cap properties according to any system limits */ #define CLAMP_PROP(field) \
dri-devel@lists.freedesktop.org
-
John Harrison -
John.C.Harrison＠Intel.com
-
Tvrtko Ursulin