On 25/04/2019 10:19, Chris Wilson wrote:
Allow the user to direct which physical engines of the virtual engine
they wish to execute one, as sometimes it is necessary to override the
load balancing algorithm.
v2: Only kick the virtual engines on context-out if required
Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Cc: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
---
drivers/gpu/drm/i915/gt/intel_lrc.c | 67 +++++++++++++
drivers/gpu/drm/i915/gt/selftest_lrc.c | 131 +++++++++++++++++++++++++
drivers/gpu/drm/i915/i915_request.c | 1 +
drivers/gpu/drm/i915/i915_request.h | 3 +
4 files changed, 202 insertions(+)
diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.c b/drivers/gpu/drm/i915/gt/intel_lrc.c
index e8faf3417f9c..8acf9d1c6f2f 100644
--- a/drivers/gpu/drm/i915/gt/intel_lrc.c
+++ b/drivers/gpu/drm/i915/gt/intel_lrc.c
@@ -549,6 +549,15 @@ execlists_context_schedule_in(struct i915_request *rq)
rq->hw_context->active = rq->engine;
}
+static void kick_siblings(struct i915_request *rq)
+{
+ struct virtual_engine *ve = to_virtual_engine(rq->hw_context->engine);
+ struct i915_request *next = READ_ONCE(ve->request);
+
+ if (next && next->execution_mask & ~rq->execution_mask)
+ tasklet_schedule(&ve->base.execlists.tasklet);
+}
+
static inline void
execlists_context_schedule_out(struct i915_request *rq, unsigned long status)
{
@@ -556,6 +565,18 @@ execlists_context_schedule_out(struct i915_request *rq, unsigned long status)
intel_engine_context_out(rq->engine);
execlists_context_status_change(rq, status);
trace_i915_request_out(rq);
+
+ /*
+ * If this is part of a virtual engine, its next request may have
+ * been blocked waiting for access to the active context. We have
+ * to kick all the siblings again in case we need to switch (e.g.
+ * the next request is not runnable on this engine). Hopefully,
+ * we will already have submitted the next request before the
+ * tasklet runs and do not need to rebuild each virtual tree
+ * and kick everyone again.
+ */
+ if (rq->engine != rq->hw_context->engine)
+ kick_siblings(rq);
}
static u64 execlists_update_context(struct i915_request *rq)
@@ -783,6 +804,9 @@ static bool virtual_matches(const struct virtual_engine *ve,
{
const struct intel_engine_cs *active;
+ if (!(rq->execution_mask & engine->mask)) /* We peeked too soon! */
+ return false;
+
/*
* We track when the HW has completed saving the context image
* (i.e. when we have seen the final CS event switching out of
@@ -3141,12 +3165,44 @@ static const struct intel_context_ops virtual_context_ops = {
.destroy = virtual_context_destroy,
};
+static intel_engine_mask_t virtual_submission_mask(struct virtual_engine *ve)
+{
+ struct i915_request *rq;
+ intel_engine_mask_t mask;
+
+ rq = READ_ONCE(ve->request);
+ if (!rq)
+ return 0;
+
+ /* The rq is ready for submission; rq->execution_mask is now stable. */
+ mask = rq->execution_mask;
+ if (unlikely(!mask)) {
+ /* Invalid selection, submit to a random engine in error */
+ i915_request_skip(rq, -ENODEV);
+ mask = ve->siblings[0]->mask;
+ }
+
+ GEM_TRACE("%s: rq=%llx:%lld, mask=%x, prio=%d\n",
+ ve->base.name,
+ rq->fence.context, rq->fence.seqno,
+ mask, ve->base.execlists.queue_priority_hint);
+
+ return mask;
+}
+
static void virtual_submission_tasklet(unsigned long data)
{
struct virtual_engine * const ve = (struct virtual_engine *)data;
const int prio = ve->base.execlists.queue_priority_hint;
+ intel_engine_mask_t mask;
unsigned int n;
+ rcu_read_lock();
+ mask = virtual_submission_mask(ve);
+ rcu_read_unlock();
+ if (unlikely(!mask))
Is the rcu_lock think solely for the same protection against wedging in
submit_notify?
Regards,
Tvrtko
+ return;
+
local_irq_disable();
for (n = 0; READ_ONCE(ve->request) && n < ve->num_siblings; n++) {
struct intel_engine_cs *sibling = ve->siblings[n];
@@ -3154,6 +3210,17 @@ static void virtual_submission_tasklet(unsigned long data)
struct rb_node **parent, *rb;
bool first;
+ if (unlikely(!(mask & sibling->mask))) {
+ if (!RB_EMPTY_NODE(&node->rb)) {
+ spin_lock(&sibling->timeline.lock);
+ rb_erase_cached(&node->rb,
+ &sibling->execlists.virtual);
+ RB_CLEAR_NODE(&node->rb);
+ spin_unlock(&sibling->timeline.lock);
+ }
+ continue;
+ }
+
spin_lock(&sibling->timeline.lock);
if (!RB_EMPTY_NODE(&node->rb)) {
diff --git a/drivers/gpu/drm/i915/gt/selftest_lrc.c b/drivers/gpu/drm/i915/gt/selftest_lrc.c
index 558399e5c7bb..73308749936c 100644
--- a/drivers/gpu/drm/i915/gt/selftest_lrc.c
+++ b/drivers/gpu/drm/i915/gt/selftest_lrc.c
@@ -1480,6 +1480,136 @@ static int live_virtual_engine(void *arg)
return err;
}
+static int mask_virtual_engine(struct drm_i915_private *i915,
+ struct intel_engine_cs **siblings,
+ unsigned int nsibling)
+{
+ struct i915_request *request[MAX_ENGINE_INSTANCE + 1];
+ struct i915_gem_context *ctx;
+ struct intel_context *ve;
+ struct igt_live_test t;
+ unsigned int n;
+ int err;
+
+ /*
+ * Check that by setting the execution mask on a request, we can
+ * restrict it to our desired engine within the virtual engine.
+ */
+
+ ctx = kernel_context(i915);
+ if (!ctx)
+ return -ENOMEM;
+
+ ve = intel_execlists_create_virtual(ctx, siblings, nsibling);
+ if (IS_ERR(ve)) {
+ err = PTR_ERR(ve);
+ goto out_close;
+ }
+
+ err = intel_context_pin(ve);
+ if (err)
+ goto out_put;
+
+ err = igt_live_test_begin(&t, i915, __func__, ve->engine->name);
+ if (err)
+ goto out_unpin;
+
+ for (n = 0; n < nsibling; n++) {
+ request[n] = i915_request_create(ve);
+ if (IS_ERR(request)) {
+ err = PTR_ERR(request);
+ nsibling = n;
+ goto out;
+ }
+
+ /* Reverse order as it's more likely to be unnatural */
+ request[n]->execution_mask = siblings[nsibling - n - 1]->mask;
+
+ i915_request_get(request[n]);
+ i915_request_add(request[n]);
+ }
+
+ for (n = 0; n < nsibling; n++) {
+ if (i915_request_wait(request[n], I915_WAIT_LOCKED, HZ / 10) < 0) {
+ pr_err("%s(%s): wait for %llx:%lld timed out\n",
+ __func__, ve->engine->name,
+ request[n]->fence.context,
+ request[n]->fence.seqno);
+
+ GEM_TRACE("%s(%s) failed at request %llx:%lld\n",
+ __func__, ve->engine->name,
+ request[n]->fence.context,
+ request[n]->fence.seqno);
+ GEM_TRACE_DUMP();
+ i915_gem_set_wedged(i915);
+ err = -EIO;
+ goto out;
+ }
+
+ if (request[n]->engine != siblings[nsibling - n - 1]) {
+ pr_err("Executed on wrong sibling '%s', expected '%s'\n",
+ request[n]->engine->name,
+ siblings[nsibling - n - 1]->name);
+ err = -EINVAL;
+ goto out;
+ }
+ }
+
+ err = igt_live_test_end(&t);
+ if (err)
+ goto out;
+
+out:
+ if (igt_flush_test(i915, I915_WAIT_LOCKED))
+ err = -EIO;
+
+ for (n = 0; n < nsibling; n++)
+ i915_request_put(request[n]);
+
+out_unpin:
+ intel_context_unpin(ve);
+out_put:
+ intel_context_put(ve);
+out_close:
+ kernel_context_close(ctx);
+ return err;
+}
+
+static int live_virtual_mask(void *arg)
+{
+ struct drm_i915_private *i915 = arg;
+ struct intel_engine_cs *siblings[MAX_ENGINE_INSTANCE + 1];
+ unsigned int class, inst;
+ int err = 0;
+
+ if (USES_GUC_SUBMISSION(i915))
+ return 0;
+
+ mutex_lock(&i915->drm.struct_mutex);
+
+ for (class = 0; class <= MAX_ENGINE_CLASS; class++) {
+ unsigned int nsibling;
+
+ nsibling = 0;
+ for (inst = 0; inst <= MAX_ENGINE_INSTANCE; inst++) {
+ if (!i915->engine_class[class][inst])
+ break;
+
+ siblings[nsibling++] = i915->engine_class[class][inst];
+ }
+ if (nsibling < 2)
+ continue;
+
+ err = mask_virtual_engine(i915, siblings, nsibling);
+ if (err)
+ goto out_unlock;
+ }
+
+out_unlock:
+ mutex_unlock(&i915->drm.struct_mutex);
+ return err;
+}
+
int intel_execlists_live_selftests(struct drm_i915_private *i915)
{
static const struct i915_subtest tests[] = {
@@ -1493,6 +1623,7 @@ int intel_execlists_live_selftests(struct drm_i915_private *i915)
SUBTEST(live_preempt_hang),
SUBTEST(live_preempt_smoke),
SUBTEST(live_virtual_engine),
+ SUBTEST(live_virtual_mask),
};
if (!HAS_EXECLISTS(i915))
diff --git a/drivers/gpu/drm/i915/i915_request.c b/drivers/gpu/drm/i915/i915_request.c
index a5a2ccc23958..06c2b89d0b0a 100644
--- a/drivers/gpu/drm/i915/i915_request.c
+++ b/drivers/gpu/drm/i915/i915_request.c
@@ -688,6 +688,7 @@ __i915_request_create(struct intel_context *ce, gfp_t gfp)
rq->batch = NULL;
rq->capture_list = NULL;
rq->waitboost = false;
+ rq->execution_mask = ALL_ENGINES;
INIT_LIST_HEAD(&rq->active_list);
INIT_LIST_HEAD(&rq->execute_cb);
diff --git a/drivers/gpu/drm/i915/i915_request.h b/drivers/gpu/drm/i915/i915_request.h
index 8025a89b5999..d7f9b2194568 100644
--- a/drivers/gpu/drm/i915/i915_request.h
+++ b/drivers/gpu/drm/i915/i915_request.h
@@ -28,6 +28,8 @@
#include <linux/dma-fence.h>
#include <linux/lockdep.h>
+#include "gt/intel_engine_types.h"
+
#include "i915_gem.h"
#include "i915_scheduler.h"
#include "i915_selftest.h"
@@ -156,6 +158,7 @@ struct i915_request {
*/
struct i915_sched_node sched;
struct i915_dependency dep;
+ intel_engine_mask_t execution_mask;
/*
* A convenience pointer to the current breadcrumb value stored in
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