[Intel-gfx] [RFC PATCH v2 2/2] Fix per client busyness locking
Ashutosh Dixit
ashutosh.dixit at intel.com
Thu Sep 1 23:54:52 UTC 2022
1. Do all ce->stats updates and reads under guc->timestamp.lock
2. Pin context image before reading
3. Merge __guc_context_update_clks and guc_context_update_stats into a
single function
4. Call lrc_update_runtime() unconditionally in guc_context_update_stats
5. Seems no need to update ce->stats.active with this approach
Some of the above steps may not be correct or complete but the idea is to
discuss/improve the original patch.
v2 (Address review comments from Umesh):
* Don't pin context when called from intel_context_get_total_runtime_ns
* Don't pin context in lrc_update_runtime_locked
* ce->stats.active is now used to cache previous active value
* Move lrc_update_runtime to else in __guc_context_update_stats
Cc: Umesh Nerlige Ramappa <umesh.nerlige.ramappa at intel.com>
Signed-off-by: Ashutosh Dixit <ashutosh.dixit at intel.com>
---
drivers/gpu/drm/i915/gt/intel_context.c | 9 +--
drivers/gpu/drm/i915/gt/intel_context_types.h | 2 +-
.../gpu/drm/i915/gt/uc/intel_guc_submission.c | 57 ++++++++++++-------
3 files changed, 40 insertions(+), 28 deletions(-)
diff --git a/drivers/gpu/drm/i915/gt/intel_context.c b/drivers/gpu/drm/i915/gt/intel_context.c
index e2d70a9fdac0..51dce98003ec 100644
--- a/drivers/gpu/drm/i915/gt/intel_context.c
+++ b/drivers/gpu/drm/i915/gt/intel_context.c
@@ -581,19 +581,14 @@ u64 intel_context_get_total_runtime_ns(struct intel_context *ce)
u64 total, active;
if (ce->ops->update_stats)
- ce->ops->update_stats(ce);
+ return ce->ops->update_stats(ce, false);
total = ce->stats.runtime.total;
if (ce->ops->flags & COPS_RUNTIME_CYCLES)
total *= ce->engine->gt->clock_period_ns;
active = READ_ONCE(ce->stats.active);
- /*
- * When COPS_RUNTIME_ACTIVE_TOTAL is set for ce->cops, the backend
- * already provides the total active time of the context, so skip this
- * calculation when this flag is set.
- */
- if (active && !(ce->ops->flags & COPS_RUNTIME_ACTIVE_TOTAL))
+ if (active)
active = intel_context_clock() - active;
return total + active;
diff --git a/drivers/gpu/drm/i915/gt/intel_context_types.h b/drivers/gpu/drm/i915/gt/intel_context_types.h
index f7ff4c7d81c7..06dad9eeecdb 100644
--- a/drivers/gpu/drm/i915/gt/intel_context_types.h
+++ b/drivers/gpu/drm/i915/gt/intel_context_types.h
@@ -59,7 +59,7 @@ struct intel_context_ops {
void (*sched_disable)(struct intel_context *ce);
- void (*update_stats)(struct intel_context *ce);
+ u64 (*update_stats)(struct intel_context *ce, bool pin);
void (*reset)(struct intel_context *ce);
void (*destroy)(struct kref *kref);
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 bee8cf10f749..b3c6f57f45cb 100644
--- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
+++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
@@ -1376,7 +1376,6 @@ static void __update_guc_busyness_stats(struct intel_guc *guc)
spin_unlock_irqrestore(&guc->timestamp.lock, flags);
}
-static void __guc_context_update_clks(struct intel_context *ce);
static void guc_timestamp_ping(struct work_struct *wrk)
{
struct intel_guc *guc = container_of(wrk, typeof(*guc),
@@ -1401,7 +1400,8 @@ static void guc_timestamp_ping(struct work_struct *wrk)
/* adjust context stats for overflow */
xa_for_each(&guc->context_lookup, index, ce)
- __guc_context_update_clks(ce);
+ if (ce->ops->update_stats)
+ ce->ops->update_stats(ce, true);
intel_gt_reset_unlock(gt, srcu);
@@ -1476,17 +1476,13 @@ void intel_guc_busyness_unpark(struct intel_gt *gt)
guc->timestamp.ping_delay);
}
-static void __guc_context_update_clks(struct intel_context *ce)
+static u64 __guc_context_update_stats(struct intel_context *ce)
{
struct intel_guc *guc = ce_to_guc(ce);
struct intel_gt *gt = ce->engine->gt;
u32 *pphwsp, last_switch, engine_id;
- u64 start_gt_clk, active;
- unsigned long flags;
ktime_t unused;
- spin_lock_irqsave(&guc->timestamp.lock, flags);
-
/*
* GPU updates ce->lrc_reg_state[CTX_TIMESTAMP] when context is switched
* out, however GuC updates PPHWSP offsets below. Hence KMD (CPU)
@@ -1502,28 +1498,49 @@ static void __guc_context_update_clks(struct intel_context *ce)
guc_update_pm_timestamp(guc, &unused);
if (engine_id != 0xffffffff && last_switch) {
- start_gt_clk = READ_ONCE(ce->stats.runtime.start_gt_clk);
- __extend_last_switch(guc, &start_gt_clk, last_switch);
- active = intel_gt_clock_interval_to_ns(gt, guc->timestamp.gt_stamp - start_gt_clk);
- WRITE_ONCE(ce->stats.runtime.start_gt_clk, start_gt_clk);
- WRITE_ONCE(ce->stats.active, active);
+ __extend_last_switch(guc, &ce->stats.runtime.start_gt_clk, last_switch);
+ ce->stats.active = intel_gt_clock_interval_to_ns(gt,
+ guc->timestamp.gt_stamp - ce->stats.runtime.start_gt_clk);
} else {
lrc_update_runtime(ce);
+ ce->stats.active = 0;
}
- spin_unlock_irqrestore(&guc->timestamp.lock, flags);
+ return ce->stats.runtime.total + ce->stats.active;
}
-static void guc_context_update_stats(struct intel_context *ce)
+u64 guc_context_update_stats(struct intel_context *ce, bool pin)
{
- if (!intel_context_pin_if_active(ce)) {
- WRITE_ONCE(ce->stats.runtime.start_gt_clk, 0);
- WRITE_ONCE(ce->stats.active, 0);
- return;
+ struct intel_guc *guc = ce_to_guc(ce);
+ unsigned long flags;
+ u64 ret;
+
+ if (pin) {
+ intel_context_pin(ce);
+ } else {
+ /* Return previously computed value */
+ spin_lock_irqsave(&guc->timestamp.lock, flags);
+ ret = ce->stats.runtime.total + ce->stats.active;
+ spin_unlock_irqrestore(&guc->timestamp.lock, flags);
+ return ret;
}
- __guc_context_update_clks(ce);
+ spin_lock_irqsave(&guc->timestamp.lock, flags);
+ ret = __guc_context_update_stats(ce);
+ spin_unlock_irqrestore(&guc->timestamp.lock, flags);
+
intel_context_unpin(ce);
+ return ret;
+}
+
+static void lrc_update_runtime_locked(struct intel_context *ce)
+{
+ struct intel_guc *guc = ce_to_guc(ce);
+ unsigned long flags;
+
+ spin_lock_irqsave(&guc->timestamp.lock, flags);
+ lrc_update_runtime(ce);
+ spin_unlock_irqrestore(&guc->timestamp.lock, flags);
}
static inline bool
@@ -2780,7 +2797,7 @@ static void guc_context_unpin(struct intel_context *ce)
{
struct intel_guc *guc = ce_to_guc(ce);
- lrc_update_runtime(ce);
+ lrc_update_runtime_locked(ce);
unpin_guc_id(guc, ce);
lrc_unpin(ce);
--
2.34.1
More information about the Intel-gfx
mailing list