Commit cd3862dc authored by Chris Wilson's avatar Chris Wilson

drm/i915: Live testing of empty requests

Primarily to emphasize the difference between just advancing the
breadcrumb using a bare request and the overhead of dispatching an
execbuffer.
Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: default avatarJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170213171558.20942-16-chris@chris-wilson.co.uk
parent 97b592b1
......@@ -338,6 +338,160 @@ static int live_nop_request(void *arg)
return err;
}
static struct i915_vma *empty_batch(struct drm_i915_private *i915)
{
struct drm_i915_gem_object *obj;
struct i915_vma *vma;
u32 *cmd;
int err;
obj = i915_gem_object_create_internal(i915, PAGE_SIZE);
if (IS_ERR(obj))
return ERR_CAST(obj);
cmd = i915_gem_object_pin_map(obj, I915_MAP_WB);
if (IS_ERR(cmd)) {
err = PTR_ERR(cmd);
goto err;
}
*cmd = MI_BATCH_BUFFER_END;
i915_gem_object_unpin_map(obj);
err = i915_gem_object_set_to_gtt_domain(obj, false);
if (err)
goto err;
vma = i915_vma_instance(obj, &i915->ggtt.base, NULL);
if (IS_ERR(vma)) {
err = PTR_ERR(vma);
goto err;
}
err = i915_vma_pin(vma, 0, 0, PIN_USER | PIN_GLOBAL);
if (err)
goto err;
return vma;
err:
i915_gem_object_put(obj);
return ERR_PTR(err);
}
static struct drm_i915_gem_request *
empty_request(struct intel_engine_cs *engine,
struct i915_vma *batch)
{
struct drm_i915_gem_request *request;
int err;
request = i915_gem_request_alloc(engine,
engine->i915->kernel_context);
if (IS_ERR(request))
return request;
err = engine->emit_flush(request, EMIT_INVALIDATE);
if (err)
goto out_request;
err = i915_switch_context(request);
if (err)
goto out_request;
err = engine->emit_bb_start(request,
batch->node.start,
batch->node.size,
I915_DISPATCH_SECURE);
if (err)
goto out_request;
out_request:
__i915_add_request(request, err == 0);
return err ? ERR_PTR(err) : request;
}
static int live_empty_request(void *arg)
{
struct drm_i915_private *i915 = arg;
struct intel_engine_cs *engine;
struct live_test t;
struct i915_vma *batch;
unsigned int id;
int err = 0;
/* Submit various sized batches of empty requests, to each engine
* (individually), and wait for the batch to complete. We can check
* the overhead of submitting requests to the hardware.
*/
mutex_lock(&i915->drm.struct_mutex);
batch = empty_batch(i915);
if (IS_ERR(batch)) {
err = PTR_ERR(batch);
goto out_unlock;
}
for_each_engine(engine, i915, id) {
IGT_TIMEOUT(end_time);
struct drm_i915_gem_request *request;
unsigned long n, prime;
ktime_t times[2] = {};
err = begin_live_test(&t, i915, __func__, engine->name);
if (err)
goto out_batch;
/* Warmup / preload */
request = empty_request(engine, batch);
if (IS_ERR(request)) {
err = PTR_ERR(request);
goto out_batch;
}
i915_wait_request(request,
I915_WAIT_LOCKED,
MAX_SCHEDULE_TIMEOUT);
for_each_prime_number_from(prime, 1, 8192) {
times[1] = ktime_get_raw();
for (n = 0; n < prime; n++) {
request = empty_request(engine, batch);
if (IS_ERR(request)) {
err = PTR_ERR(request);
goto out_batch;
}
}
i915_wait_request(request,
I915_WAIT_LOCKED,
MAX_SCHEDULE_TIMEOUT);
times[1] = ktime_sub(ktime_get_raw(), times[1]);
if (prime == 1)
times[0] = times[1];
if (__igt_timeout(end_time, NULL))
break;
}
err = end_live_test(&t);
if (err)
goto out_batch;
pr_info("Batch latencies on %s: 1 = %lluns, %lu = %lluns\n",
engine->name,
ktime_to_ns(times[0]),
prime, div64_u64(ktime_to_ns(times[1]), prime));
}
out_batch:
i915_vma_unpin(batch);
i915_vma_put(batch);
out_unlock:
mutex_unlock(&i915->drm.struct_mutex);
return err;
}
static struct i915_vma *recursive_batch(struct drm_i915_private *i915)
{
struct i915_gem_context *ctx = i915->kernel_context;
......@@ -658,6 +812,7 @@ int i915_gem_request_live_selftests(struct drm_i915_private *i915)
SUBTEST(live_nop_request),
SUBTEST(live_all_engines),
SUBTEST(live_sequential_engines),
SUBTEST(live_empty_request),
};
return i915_subtests(tests, i915);
}
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