| Message ID | 20201020161144.678668-1-tvrtko.ursulin@linux.intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | None | expand |
Quoting Tvrtko Ursulin (2020-10-20 17:11:44) > From: Tvrtko Ursulin <tvrtko.ursulin@intel.com> > > Since we keep a driver global mask of online CPUs and base the decision > whether PMU needs to be migrated upon it, we need to make sure the > migration is done for all registered PMUs (so GPUs). > > To do this we need to track the current CPU for each PMU and base the > decision on whether to migrate on a comparison between global and local > state. > > At the same time, since dynamic CPU hotplug notification slots are a > scarce resource and given how we already register the multi instance type > state, we can and should add multiple instance of the i915 PMU to this > same state and not allocate a new one for every GPU. > > v2: > * Use pr_notice. (Chris) > > v3: > * Handle a nasty interaction where unregistration which triggers a false > CPU offline event. (Chris) > > Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com> > Suggested-by: Daniel Vetter <daniel.vetter@intel.com> # dynamic slot optimisation > Cc: Chris Wilson <chris@chris-wilson.co.uk> > --- > drivers/gpu/drm/i915/i915_pci.c | 7 +++- > drivers/gpu/drm/i915/i915_pmu.c | 57 +++++++++++++++++++++------------ > drivers/gpu/drm/i915/i915_pmu.h | 6 +++- > 3 files changed, 48 insertions(+), 22 deletions(-) > > diff --git a/drivers/gpu/drm/i915/i915_pci.c b/drivers/gpu/drm/i915/i915_pci.c > index 27964ac0638a..a384f51c91c1 100644 > --- a/drivers/gpu/drm/i915/i915_pci.c > +++ b/drivers/gpu/drm/i915/i915_pci.c > @@ -1150,9 +1150,13 @@ static int __init i915_init(void) > return 0; > } > > + i915_pmu_init(); > + > err = pci_register_driver(&i915_pci_driver); > - if (err) > + if (err) { > + i915_pmu_exit(); > return err; We could do an onion bhaji and call i915_globals_exit() as well. > + } > > i915_perf_sysctl_register(); > return 0; > @@ -1166,6 +1170,7 @@ static void __exit i915_exit(void) > i915_perf_sysctl_unregister(); > pci_unregister_driver(&i915_pci_driver); > i915_globals_exit(); > + i915_pmu_exit(); pmu_exit then globals_exit to pair with i915_init? > } > > module_init(i915_init); > diff --git a/drivers/gpu/drm/i915/i915_pmu.c b/drivers/gpu/drm/i915/i915_pmu.c > index 51ed7d0efcdc..cd786ad12be7 100644 > --- a/drivers/gpu/drm/i915/i915_pmu.c > +++ b/drivers/gpu/drm/i915/i915_pmu.c > @@ -30,6 +30,7 @@ > #define ENGINE_SAMPLE_BITS (1 << I915_PMU_SAMPLE_BITS) > > static cpumask_t i915_pmu_cpumask; > +static unsigned int i915_pmu_target_cpu = -1; > > static u8 engine_config_sample(u64 config) > { > @@ -1049,25 +1050,39 @@ static int i915_pmu_cpu_online(unsigned int cpu, struct hlist_node *node) > static int i915_pmu_cpu_offline(unsigned int cpu, struct hlist_node *node) > { > struct i915_pmu *pmu = hlist_entry_safe(node, typeof(*pmu), cpuhp.node); > - unsigned int target; > + unsigned int target = i915_pmu_target_cpu; > > GEM_BUG_ON(!pmu->base.event_init); > > + /* > + * Unregistering an instance generates a CPU offline event which we must > + * ignore to avoid incorrectly modifying the shared i915_pmu_cpumask. > + */ > + if (pmu->closed) > + return 0; > + > if (cpumask_test_and_clear_cpu(cpu, &i915_pmu_cpumask)) { > target = cpumask_any_but(topology_sibling_cpumask(cpu), cpu); > + > /* Migrate events if there is a valid target */ > if (target < nr_cpu_ids) { > cpumask_set_cpu(target, &i915_pmu_cpumask); > - perf_pmu_migrate_context(&pmu->base, cpu, target); > + i915_pmu_target_cpu = target; > } > } > > + if (target < nr_cpu_ids && target != pmu->cpuhp.cpu) { > + perf_pmu_migrate_context(&pmu->base, cpu, target); > + pmu->cpuhp.cpu = target; > + } > + > return 0; > } > > -static int i915_pmu_register_cpuhp_state(struct i915_pmu *pmu) > +static enum cpuhp_state cpuhp_slot = CPUHP_INVALID; > + > +void i915_pmu_init(void) > { > - enum cpuhp_state slot; > int ret; > > ret = cpuhp_setup_state_multi(CPUHP_AP_ONLINE_DYN, > @@ -1075,27 +1090,29 @@ static int i915_pmu_register_cpuhp_state(struct i915_pmu *pmu) > i915_pmu_cpu_online, > i915_pmu_cpu_offline); > if (ret < 0) > - return ret; > + pr_notice("Failed to setup cpuhp state for i915 PMU! (%d)\n", > + ret); > + else > + cpuhp_slot = ret; > +} > > - slot = ret; > - ret = cpuhp_state_add_instance(slot, &pmu->cpuhp.node); > - if (ret) { > - cpuhp_remove_multi_state(slot); > - return ret; > - } > +void i915_pmu_exit(void) > +{ > + if (cpuhp_slot != CPUHP_INVALID) > + cpuhp_remove_multi_state(cpuhp_slot); > +} > > - pmu->cpuhp.slot = slot; > - return 0; > +static int i915_pmu_register_cpuhp_state(struct i915_pmu *pmu) > +{ > + if (cpuhp_slot == CPUHP_INVALID) > + return -EINVAL; > + > + return cpuhp_state_add_instance(cpuhp_slot, &pmu->cpuhp.node); > } > > static void i915_pmu_unregister_cpuhp_state(struct i915_pmu *pmu) > { > - struct drm_i915_private *i915 = container_of(pmu, typeof(*i915), pmu); > - > - drm_WARN_ON(&i915->drm, pmu->cpuhp.slot == CPUHP_INVALID); > - drm_WARN_ON(&i915->drm, cpuhp_state_remove_instance(pmu->cpuhp.slot, &pmu->cpuhp.node)); > - cpuhp_remove_multi_state(pmu->cpuhp.slot); > - pmu->cpuhp.slot = CPUHP_INVALID; > + cpuhp_state_remove_instance(cpuhp_slot, &pmu->cpuhp.node); > } > > static bool is_igp(struct drm_i915_private *i915) > @@ -1129,7 +1146,7 @@ void i915_pmu_register(struct drm_i915_private *i915) > spin_lock_init(&pmu->lock); > hrtimer_init(&pmu->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); > pmu->timer.function = i915_sample; > - pmu->cpuhp.slot = CPUHP_INVALID; > + pmu->cpuhp.cpu = -1; To the best of my limited understanding of cpuhp, Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk> -Chris
On 20/10/2020 17:19, Chris Wilson wrote: > Quoting Tvrtko Ursulin (2020-10-20 17:11:44) >> From: Tvrtko Ursulin <tvrtko.ursulin@intel.com> >> >> Since we keep a driver global mask of online CPUs and base the decision >> whether PMU needs to be migrated upon it, we need to make sure the >> migration is done for all registered PMUs (so GPUs). >> >> To do this we need to track the current CPU for each PMU and base the >> decision on whether to migrate on a comparison between global and local >> state. >> >> At the same time, since dynamic CPU hotplug notification slots are a >> scarce resource and given how we already register the multi instance type >> state, we can and should add multiple instance of the i915 PMU to this >> same state and not allocate a new one for every GPU. >> >> v2: >> * Use pr_notice. (Chris) >> >> v3: >> * Handle a nasty interaction where unregistration which triggers a false >> CPU offline event. (Chris) >> >> Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com> >> Suggested-by: Daniel Vetter <daniel.vetter@intel.com> # dynamic slot optimisation >> Cc: Chris Wilson <chris@chris-wilson.co.uk> >> --- >> drivers/gpu/drm/i915/i915_pci.c | 7 +++- >> drivers/gpu/drm/i915/i915_pmu.c | 57 +++++++++++++++++++++------------ >> drivers/gpu/drm/i915/i915_pmu.h | 6 +++- >> 3 files changed, 48 insertions(+), 22 deletions(-) >> >> diff --git a/drivers/gpu/drm/i915/i915_pci.c b/drivers/gpu/drm/i915/i915_pci.c >> index 27964ac0638a..a384f51c91c1 100644 >> --- a/drivers/gpu/drm/i915/i915_pci.c >> +++ b/drivers/gpu/drm/i915/i915_pci.c >> @@ -1150,9 +1150,13 @@ static int __init i915_init(void) >> return 0; >> } >> >> + i915_pmu_init(); >> + >> err = pci_register_driver(&i915_pci_driver); >> - if (err) >> + if (err) { >> + i915_pmu_exit(); >> return err; > > We could do an onion bhaji and call i915_globals_exit() as well. > >> + } >> >> i915_perf_sysctl_register(); >> return 0; >> @@ -1166,6 +1170,7 @@ static void __exit i915_exit(void) >> i915_perf_sysctl_unregister(); >> pci_unregister_driver(&i915_pci_driver); >> i915_globals_exit(); >> + i915_pmu_exit(); > > pmu_exit then globals_exit to pair with i915_init? Maybe later, sorry. >> } >> >> module_init(i915_init); >> diff --git a/drivers/gpu/drm/i915/i915_pmu.c b/drivers/gpu/drm/i915/i915_pmu.c >> index 51ed7d0efcdc..cd786ad12be7 100644 >> --- a/drivers/gpu/drm/i915/i915_pmu.c >> +++ b/drivers/gpu/drm/i915/i915_pmu.c >> @@ -30,6 +30,7 @@ >> #define ENGINE_SAMPLE_BITS (1 << I915_PMU_SAMPLE_BITS) >> >> static cpumask_t i915_pmu_cpumask; >> +static unsigned int i915_pmu_target_cpu = -1; >> >> static u8 engine_config_sample(u64 config) >> { >> @@ -1049,25 +1050,39 @@ static int i915_pmu_cpu_online(unsigned int cpu, struct hlist_node *node) >> static int i915_pmu_cpu_offline(unsigned int cpu, struct hlist_node *node) >> { >> struct i915_pmu *pmu = hlist_entry_safe(node, typeof(*pmu), cpuhp.node); >> - unsigned int target; >> + unsigned int target = i915_pmu_target_cpu; >> >> GEM_BUG_ON(!pmu->base.event_init); >> >> + /* >> + * Unregistering an instance generates a CPU offline event which we must >> + * ignore to avoid incorrectly modifying the shared i915_pmu_cpumask. >> + */ >> + if (pmu->closed) >> + return 0; >> + >> if (cpumask_test_and_clear_cpu(cpu, &i915_pmu_cpumask)) { >> target = cpumask_any_but(topology_sibling_cpumask(cpu), cpu); >> + >> /* Migrate events if there is a valid target */ >> if (target < nr_cpu_ids) { >> cpumask_set_cpu(target, &i915_pmu_cpumask); >> - perf_pmu_migrate_context(&pmu->base, cpu, target); >> + i915_pmu_target_cpu = target; >> } >> } >> >> + if (target < nr_cpu_ids && target != pmu->cpuhp.cpu) { >> + perf_pmu_migrate_context(&pmu->base, cpu, target); >> + pmu->cpuhp.cpu = target; >> + } >> + >> return 0; >> } >> >> -static int i915_pmu_register_cpuhp_state(struct i915_pmu *pmu) >> +static enum cpuhp_state cpuhp_slot = CPUHP_INVALID; >> + >> +void i915_pmu_init(void) >> { >> - enum cpuhp_state slot; >> int ret; >> >> ret = cpuhp_setup_state_multi(CPUHP_AP_ONLINE_DYN, >> @@ -1075,27 +1090,29 @@ static int i915_pmu_register_cpuhp_state(struct i915_pmu *pmu) >> i915_pmu_cpu_online, >> i915_pmu_cpu_offline); >> if (ret < 0) >> - return ret; >> + pr_notice("Failed to setup cpuhp state for i915 PMU! (%d)\n", >> + ret); >> + else >> + cpuhp_slot = ret; >> +} >> >> - slot = ret; >> - ret = cpuhp_state_add_instance(slot, &pmu->cpuhp.node); >> - if (ret) { >> - cpuhp_remove_multi_state(slot); >> - return ret; >> - } >> +void i915_pmu_exit(void) >> +{ >> + if (cpuhp_slot != CPUHP_INVALID) >> + cpuhp_remove_multi_state(cpuhp_slot); >> +} >> >> - pmu->cpuhp.slot = slot; >> - return 0; >> +static int i915_pmu_register_cpuhp_state(struct i915_pmu *pmu) >> +{ >> + if (cpuhp_slot == CPUHP_INVALID) >> + return -EINVAL; >> + >> + return cpuhp_state_add_instance(cpuhp_slot, &pmu->cpuhp.node); >> } >> >> static void i915_pmu_unregister_cpuhp_state(struct i915_pmu *pmu) >> { >> - struct drm_i915_private *i915 = container_of(pmu, typeof(*i915), pmu); >> - >> - drm_WARN_ON(&i915->drm, pmu->cpuhp.slot == CPUHP_INVALID); >> - drm_WARN_ON(&i915->drm, cpuhp_state_remove_instance(pmu->cpuhp.slot, &pmu->cpuhp.node)); >> - cpuhp_remove_multi_state(pmu->cpuhp.slot); >> - pmu->cpuhp.slot = CPUHP_INVALID; >> + cpuhp_state_remove_instance(cpuhp_slot, &pmu->cpuhp.node); >> } >> >> static bool is_igp(struct drm_i915_private *i915) >> @@ -1129,7 +1146,7 @@ void i915_pmu_register(struct drm_i915_private *i915) >> spin_lock_init(&pmu->lock); >> hrtimer_init(&pmu->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); >> pmu->timer.function = i915_sample; >> - pmu->cpuhp.slot = CPUHP_INVALID; >> + pmu->cpuhp.cpu = -1; > > To the best of my limited understanding of cpuhp, > Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk> Pushed these two, having declared shard runs flip-flops are unrelated. Thanks! Regards, Tvrtko
diff --git a/drivers/gpu/drm/i915/i915_pci.c b/drivers/gpu/drm/i915/i915_pci.c index 27964ac0638a..a384f51c91c1 100644 --- a/drivers/gpu/drm/i915/i915_pci.c +++ b/drivers/gpu/drm/i915/i915_pci.c @@ -1150,9 +1150,13 @@ static int __init i915_init(void) return 0; } + i915_pmu_init(); + err = pci_register_driver(&i915_pci_driver); - if (err) + if (err) { + i915_pmu_exit(); return err; + } i915_perf_sysctl_register(); return 0; @@ -1166,6 +1170,7 @@ static void __exit i915_exit(void) i915_perf_sysctl_unregister(); pci_unregister_driver(&i915_pci_driver); i915_globals_exit(); + i915_pmu_exit(); } module_init(i915_init); diff --git a/drivers/gpu/drm/i915/i915_pmu.c b/drivers/gpu/drm/i915/i915_pmu.c index 51ed7d0efcdc..cd786ad12be7 100644 --- a/drivers/gpu/drm/i915/i915_pmu.c +++ b/drivers/gpu/drm/i915/i915_pmu.c @@ -30,6 +30,7 @@ #define ENGINE_SAMPLE_BITS (1 << I915_PMU_SAMPLE_BITS) static cpumask_t i915_pmu_cpumask; +static unsigned int i915_pmu_target_cpu = -1; static u8 engine_config_sample(u64 config) { @@ -1049,25 +1050,39 @@ static int i915_pmu_cpu_online(unsigned int cpu, struct hlist_node *node) static int i915_pmu_cpu_offline(unsigned int cpu, struct hlist_node *node) { struct i915_pmu *pmu = hlist_entry_safe(node, typeof(*pmu), cpuhp.node); - unsigned int target; + unsigned int target = i915_pmu_target_cpu; GEM_BUG_ON(!pmu->base.event_init); + /* + * Unregistering an instance generates a CPU offline event which we must + * ignore to avoid incorrectly modifying the shared i915_pmu_cpumask. + */ + if (pmu->closed) + return 0; + if (cpumask_test_and_clear_cpu(cpu, &i915_pmu_cpumask)) { target = cpumask_any_but(topology_sibling_cpumask(cpu), cpu); + /* Migrate events if there is a valid target */ if (target < nr_cpu_ids) { cpumask_set_cpu(target, &i915_pmu_cpumask); - perf_pmu_migrate_context(&pmu->base, cpu, target); + i915_pmu_target_cpu = target; } } + if (target < nr_cpu_ids && target != pmu->cpuhp.cpu) { + perf_pmu_migrate_context(&pmu->base, cpu, target); + pmu->cpuhp.cpu = target; + } + return 0; } -static int i915_pmu_register_cpuhp_state(struct i915_pmu *pmu) +static enum cpuhp_state cpuhp_slot = CPUHP_INVALID; + +void i915_pmu_init(void) { - enum cpuhp_state slot; int ret; ret = cpuhp_setup_state_multi(CPUHP_AP_ONLINE_DYN, @@ -1075,27 +1090,29 @@ static int i915_pmu_register_cpuhp_state(struct i915_pmu *pmu) i915_pmu_cpu_online, i915_pmu_cpu_offline); if (ret < 0) - return ret; + pr_notice("Failed to setup cpuhp state for i915 PMU! (%d)\n", + ret); + else + cpuhp_slot = ret; +} - slot = ret; - ret = cpuhp_state_add_instance(slot, &pmu->cpuhp.node); - if (ret) { - cpuhp_remove_multi_state(slot); - return ret; - } +void i915_pmu_exit(void) +{ + if (cpuhp_slot != CPUHP_INVALID) + cpuhp_remove_multi_state(cpuhp_slot); +} - pmu->cpuhp.slot = slot; - return 0; +static int i915_pmu_register_cpuhp_state(struct i915_pmu *pmu) +{ + if (cpuhp_slot == CPUHP_INVALID) + return -EINVAL; + + return cpuhp_state_add_instance(cpuhp_slot, &pmu->cpuhp.node); } static void i915_pmu_unregister_cpuhp_state(struct i915_pmu *pmu) { - struct drm_i915_private *i915 = container_of(pmu, typeof(*i915), pmu); - - drm_WARN_ON(&i915->drm, pmu->cpuhp.slot == CPUHP_INVALID); - drm_WARN_ON(&i915->drm, cpuhp_state_remove_instance(pmu->cpuhp.slot, &pmu->cpuhp.node)); - cpuhp_remove_multi_state(pmu->cpuhp.slot); - pmu->cpuhp.slot = CPUHP_INVALID; + cpuhp_state_remove_instance(cpuhp_slot, &pmu->cpuhp.node); } static bool is_igp(struct drm_i915_private *i915) @@ -1129,7 +1146,7 @@ void i915_pmu_register(struct drm_i915_private *i915) spin_lock_init(&pmu->lock); hrtimer_init(&pmu->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); pmu->timer.function = i915_sample; - pmu->cpuhp.slot = CPUHP_INVALID; + pmu->cpuhp.cpu = -1; if (!is_igp(i915)) { pmu->name = kasprintf(GFP_KERNEL, diff --git a/drivers/gpu/drm/i915/i915_pmu.h b/drivers/gpu/drm/i915/i915_pmu.h index 59a0d19afb67..a24885ab415c 100644 --- a/drivers/gpu/drm/i915/i915_pmu.h +++ b/drivers/gpu/drm/i915/i915_pmu.h @@ -43,7 +43,7 @@ struct i915_pmu { */ struct { struct hlist_node node; - enum cpuhp_state slot; + unsigned int cpu; } cpuhp; /** * @base: PMU base. @@ -126,11 +126,15 @@ struct i915_pmu { }; #ifdef CONFIG_PERF_EVENTS +void i915_pmu_init(void); +void i915_pmu_exit(void); void i915_pmu_register(struct drm_i915_private *i915); void i915_pmu_unregister(struct drm_i915_private *i915); void i915_pmu_gt_parked(struct drm_i915_private *i915); void i915_pmu_gt_unparked(struct drm_i915_private *i915); #else +static inline void i915_pmu_init(void) {} +static inline void i915_pmu_exit(void) {} static inline void i915_pmu_register(struct drm_i915_private *i915) {} static inline void i915_pmu_unregister(struct drm_i915_private *i915) {} static inline void i915_pmu_gt_parked(struct drm_i915_private *i915) {}