On 14/11/2019 22:57, Chris Wilson wrote:
Verify that we can execute a long chain of dependent requests from
userspace, each one slightly more important than the last.
Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Cc: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
---
drivers/gpu/drm/i915/gt/selftest_lrc.c | 196 +++++++++++++++++++++++++
1 file changed, 196 insertions(+)
diff --git a/drivers/gpu/drm/i915/gt/selftest_lrc.c b/drivers/gpu/drm/i915/gt/selftest_lrc.c
index d1ed3c0f851c..2ef03a8efa28 100644
--- a/drivers/gpu/drm/i915/gt/selftest_lrc.c
+++ b/drivers/gpu/drm/i915/gt/selftest_lrc.c
@@ -1915,6 +1915,201 @@ static int live_chain_preempt(void *arg)
goto err_client_lo;
}
+static int create_gang(struct intel_engine_cs *engine,
+ struct i915_request **prev)
+{
+ struct drm_i915_gem_object *obj;
+ struct intel_context *ce;
+ struct i915_request *rq;
+ struct i915_vma *vma;
+ u32 *cs;
+ int err;
+
+ ce = intel_context_create(engine->kernel_context->gem_context, engine);
+ if (IS_ERR(ce))
+ return PTR_ERR(ce);
+
+ obj = i915_gem_object_create_internal(engine->i915, 4096);
+ if (IS_ERR(obj)) {
+ err = PTR_ERR(obj);
+ goto err_ce;
+ }
+
+ vma = i915_vma_instance(obj, ce->vm, NULL);
+ if (IS_ERR(vma)) {
+ err = PTR_ERR(vma);
+ goto err_obj;
+ }
+
+ err = i915_vma_pin(vma, 0, 0, PIN_USER);
+ if (err)
+ goto err_obj;
+
+ cs = i915_gem_object_pin_map(obj, I915_MAP_WC);
+ if (IS_ERR(cs))
+ goto err_obj;
+
+ /* Semaphore target: spin until zero */
+ *cs++ = MI_ARB_ON_OFF | MI_ARB_ENABLE;
+
+ *cs++ = MI_SEMAPHORE_WAIT |
+ MI_SEMAPHORE_POLL |
+ MI_SEMAPHORE_SAD_EQ_SDD;
+ *cs++ = 0;
+ *cs++ = lower_32_bits(vma->node.start);
+ *cs++ = upper_32_bits(vma->node.start);
+
+ if (*prev) {
+ u64 offset = (*prev)->batch->node.start;
+
+ /* Terminate the spinner in the next lower priority batch. */
+ *cs++ = MI_STORE_DWORD_IMM_GEN4;
+ *cs++ = lower_32_bits(offset);
+ *cs++ = upper_32_bits(offset);
+ *cs++ = 0;
+ }
+
+ *cs++ = MI_BATCH_BUFFER_END;
+ i915_gem_object_flush_map(obj);
+ i915_gem_object_unpin_map(obj);
+
+ rq = intel_context_create_request(ce);
+ if (IS_ERR(rq))
+ goto err_obj;
+
+ rq->batch = vma;
+ i915_request_get(rq);
+
+ i915_vma_lock(vma);
+ err = i915_request_await_object(rq, vma->obj, false);
+ if (!err)
+ err = i915_vma_move_to_active(vma, rq, 0);
+ if (!err)
+ err = rq->engine->emit_bb_start(rq,
+ vma->node.start,
+ PAGE_SIZE, 0);
+ i915_vma_unlock(vma);
+ i915_request_add(rq);
+ if (err)
+ goto err_rq;
+
+ i915_gem_object_put(obj);
+ intel_context_put(ce);
+
+ rq->client_link.next = &(*prev)->client_link;
+ *prev = rq;
+ return 0;
+
+err_rq:
+ i915_request_put(rq);
+err_obj:
+ i915_gem_object_put(obj);
+err_ce:
+ intel_context_put(ce);
+ return err;
+}
+
+static int live_preempt_gang(void *arg)
+{
+ struct intel_gt *gt = arg;
+ struct intel_engine_cs *engine;
+ enum intel_engine_id id;
+
+ if (!HAS_LOGICAL_RING_PREEMPTION(gt->i915))
+ return 0;
+
+ /*
+ * Build as long a chain of preempters as we can, with each
+ * request higher priority than the last. Once we are ready, we release
+ * the last batch which then precolates down the chain, each releasing
+ * the next oldest in turn. The intent is to simply push as hard as we
+ * can with the number of preemptions, trying to exceed narrow HW
+ * limits. At a minimum, we insist that we can sort all the user
+ * high priority levels into execution order.
+ */
+
+ for_each_engine(engine, gt, id) {
+ struct i915_request *rq = NULL;
+ struct igt_live_test t;
+ IGT_TIMEOUT(end_time);
+ int prio = 0;
+ int err = 0;
+ u32 *cs;
+
+ if (!intel_engine_has_preemption(engine))
+ continue;
+
+ if (igt_live_test_begin(&t, gt->i915, __func__, engine->name))
+ return -EIO;
+
+ do {
+ struct i915_sched_attr attr = {
+ .priority = I915_USER_PRIORITY(prio++),
+ };
+
+ err = create_gang(engine, &rq);
+ if (err)
+ break;
+
+ /* Submit each spinner at increasing priority */
+ engine->schedule(rq, &attr);
+
+ if (prio <= I915_PRIORITY_MAX)
+ continue;
+
+ if (prio > (INT_MAX >> I915_USER_PRIORITY_SHIFT))
+ break;
+
+ if (__igt_timeout(end_time, NULL))
+ break;
+ } while (1);
+ pr_debug("%s: Preempt chain of %d requests\n",
+ engine->name, prio);
+
+ /*
+ * Such that the last spinner is the higher priority and
+ * should execute first. When that spinner completes,
+ * it will terminate the next lowest spinner until there
+ * are no more spinners and the gang is complete.
+ */
+ cs = i915_gem_object_pin_map(rq->batch->obj, I915_MAP_WC);
+ if (!IS_ERR(cs)) {
+ *cs = 0;
+ i915_gem_object_unpin_map(rq->batch->obj);
+ } else {
+ err = PTR_ERR(cs);
+ intel_gt_set_wedged(gt);
+ }
+
+ while (rq) { /* wait for each rq from highest to lowest prio */
+ struct i915_request *n =
+ list_next_entry(rq, client_link);
+
+ if (err == 0 && i915_request_wait(rq, 0, HZ / 5) < 0) {
+ struct drm_printer p =
+ drm_info_printer(engine->i915->drm.dev);
+
+ pr_err("Failed to flush chain of %d requests, at %d\n",
+ prio, rq_prio(rq) >> I915_USER_PRIORITY_SHIFT);
+ intel_engine_dump(engine, &p,
+ "%s\n", engine->name);
+
+ err = -ETIME;
+ }
+
+ i915_request_put(rq);
+ rq = n;
+ }
+
+ if (igt_live_test_end(&t))
+ err = -EIO;
+ if (err)
+ return err;
+ }
+
+ return 0;
+}
+
static int live_preempt_hang(void *arg)
{
struct intel_gt *gt = arg;
@@ -3028,6 +3223,7 @@ int intel_execlists_live_selftests(struct drm_i915_private *i915)
SUBTEST(live_suppress_self_preempt),
SUBTEST(live_suppress_wait_preempt),
SUBTEST(live_chain_preempt),
+ SUBTEST(live_preempt_gang),
SUBTEST(live_preempt_hang),
SUBTEST(live_preempt_timeout),
SUBTEST(live_preempt_smoke),
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
Regards,
Tvrtko
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