Re: [igt-dev] [PATCH i-g-t 1/2] RFC tests/xe: Add a test that validates idle residency on exec

["Nilawar, Badal" <badal.nilawar@intel.com>]

Hi Riana,

On 11-08-2023 16:02, Riana Tauro wrote:
> Add a test what runs a background load that is
> active approximately 1% of the time. Verify that we do enter
> GT-C6 the rest of the time and validate idle residency is within
> tolerance.
> 
> Signed-off-by: Riana Tauro <riana.tauro@intel.com>
> ---
>   tests/xe/xe_pm_residency.c | 135 ++++++++++++++++++++++++++++++++++++-
>   1 file changed, 133 insertions(+), 2 deletions(-)
> 
> diff --git a/tests/xe/xe_pm_residency.c b/tests/xe/xe_pm_residency.c
> index 4936de166..abf07c696 100644
> --- a/tests/xe/xe_pm_residency.c
> +++ b/tests/xe/xe_pm_residency.c
> @@ -11,13 +11,18 @@
>    * Test category: functionality test
>    */
>   
> +#include <time.h>
> +
>   #include "igt.h"
>   #include "igt_sysfs.h"
>   
> +#include "lib/igt_syncobj.h"
> +
> +#include "xe/xe_ioctl.h"
>   #include "xe/xe_query.h"
>   #include "xe/xe_util.h"
>   
> -#define SLEEP_DURATION 3000 /* in milliseconds */
> +#define SLEEP_DURATION 3 /* in seconds */
>   
>   const double tolerance = 0.1;
>   
> @@ -38,9 +43,98 @@ const double tolerance = 0.1;
>    * Description: basic residency test to validate idle residency
>    *		measured over a time interval is within the tolerance
>    * Run type: FULL
> + *
> + * SUBTEST: idle-residency-on-exec
> + * Description: Validate idle residency measured when a background
> + *		is only active for ~1% of the time
> + * Run type: FULL
>    */
>   IGT_TEST_DESCRIPTION("Tests for gtidle properties");
>   
> +static void exec_load(int fd, struct drm_xe_engine_class_instance *hwe, unsigned long *done)
> +{
> +	uint32_t bo = 0;
> +	uint32_t exec_queue, syncobj, vm;
> +	uint64_t addr = 0x1a0000;
> +	uint64_t batch_addr, batch_offset, data_addr, data_offset;
> +	size_t bo_size;
> +	int b;
> +	struct {
> +		uint32_t batch[16];
> +		uint64_t pad;
> +		uint32_t data;
> +	} *data;
> +
> +	struct drm_xe_sync sync = {
> +		.flags = DRM_XE_SYNC_SYNCOBJ | DRM_XE_SYNC_SIGNAL,
> +	};
> +
> +	struct drm_xe_exec exec = {
> +		.num_batch_buffer = 1,
> +		.num_syncs = 1,
> +		.syncs = to_user_pointer(&sync),
> +	};
> +
> +	vm = xe_vm_create(fd, 0, 0);
> +	exec_queue = xe_exec_queue_create(fd, vm, hwe, 0);
> +	bo_size = xe_get_default_alignment(fd);
> +
> +	bo = xe_bo_create_flags(fd, vm, bo_size,
> +				visible_vram_if_possible(fd, hwe->gt_id));
> +	data = xe_bo_map(fd, bo, bo_size);
> +	syncobj = syncobj_create(fd, 0);
> +
> +	xe_vm_bind_sync(fd, vm, bo, 0, addr, bo_size);
> +
> +	batch_offset = (char *)&data->batch - (char *)data;
> +	batch_addr = addr + batch_offset;
> +	data_offset = (char *)&data->data - (char *)data;
> +	data_addr = addr + data_offset;
> +
> +	do {
> +		uint64_t submit, elapsed;
> +		struct timespec tv = {};
> +
> +		b = 0;
> +		done[1]++;
> +		data->batch[b++] = MI_STORE_DWORD_IMM_GEN4;
> +		data->batch[b++] = data_addr;
> +		data->batch[b++] = data_addr >> 32;
> +		data->batch[b++] = done[1];
> +		data->batch[b++] = MI_BATCH_BUFFER_END;
> +		igt_assert(b <= ARRAY_SIZE(data->batch));
Curious to know why MI_BATCH_BUFFER_START is not needed in batch buffer.
> +
> +		exec.exec_queue_id = exec_queue;
> +		exec.address = batch_addr;
> +		sync.handle = syncobj;
> +
> +		igt_nsec_elapsed(&tv);
> +		xe_exec(fd, &exec);
> +		submit = igt_nsec_elapsed(&tv);
> +
> +		igt_assert(syncobj_wait(fd, &syncobj, 1, INT64_MAX, 0, NULL));
> +		elapsed = igt_nsec_elapsed(&tv);
> +		igt_assert_eq(data->data, done[1]);
> +
> +		igt_debug("Execution took %.3fms (submit %.1fus, wait %.1fus)\n",
> +			  1e-6 * elapsed,
> +			  1e-3 * submit,
> +			  1e-3 * (elapsed - submit));
> +
> +		syncobj_reset(fd, &syncobj, 1);
> +
> +		/* Aim for ~1% busy */
This is sleep for 99% of execution (elapsed) time? May be you can add 
some explanation with example here.
> +		usleep(elapsed / 10);
> +	} while (!READ_ONCE(*done));
> +
> +	xe_vm_unbind_sync(fd, vm, 0, addr, bo_size);
> +	syncobj_destroy(fd, syncobj);
> +	munmap(data, bo_size);
> +	gem_close(fd, bo);
> +	xe_exec_queue_destroy(fd, exec_queue);
> +	xe_vm_destroy(fd, vm);
> +}
> +
>   static unsigned int measured_usleep(unsigned int usec)
>   {
>   	struct timespec ts = { };
> @@ -76,7 +170,7 @@ static void test_idle_residency(int fd, int gt)
>   	igt_assert_f(igt_wait(xe_is_gt_in_c6(fd, gt), 1000, 1), "GT not in C6\n");
>   
>   	residency_start = read_idle_residency(fd, gt);
> -	elapsed_ms = measured_usleep(SLEEP_DURATION * 1000) / 1000;
> +	elapsed_ms = measured_usleep(SLEEP_DURATION * USEC_PER_SEC) / 1000;
>   	residency_end = read_idle_residency(fd, gt);
>   
>   	igt_info("Measured %lums of idle residency in %lums\n",
> @@ -85,9 +179,41 @@ static void test_idle_residency(int fd, int gt)
>   	assert_within_epsilon(residency_end - residency_start, elapsed_ms, tolerance);
>   }
>   
> +static void idle_residency_on_exec(int fd, struct drm_xe_engine_class_instance *hwe)
> +{
> +	const int tol = 20;
> +	unsigned long *done;
> +	unsigned long cycles, elapsed_ms, residency;
> +
> +	done = mmap(0, 4096, PROT_WRITE, MAP_SHARED | MAP_ANON, -1, 0);
> +	igt_assert(done != MAP_FAILED);
> +	memset(done, 0, 4096);
> +
> +	igt_fork(child, 1)
> +		exec_load(fd, hwe, done);
> +
> +	cycles -= READ_ONCE(done[1]);
> +	residency -= read_idle_residency(fd, hwe->gt_id);
> +	elapsed_ms = measured_usleep(SLEEP_DURATION * USEC_PER_SEC) / 1000;
> +	residency += read_idle_residency(fd, hwe->gt_id);
> +	cycles += READ_ONCE(done[1]);
As discussed use separate variables for start and end here.
> +	*done = 1;
> +
> +	igt_waitchildren();
> +
> +	/* At least one wakeup/s needed for a reasonable test */
> +	igt_assert(cycles >= SLEEP_DURATION);
> +
> +	/* While very nearly busy, expect full GT C6 */
> +	assert_within_epsilon(residency, elapsed_ms, tol);
I think residency will always be less than elapsed time.

Regards,
Badal
> +
> +	munmap(done, 4096);
> +}
> +
>   igt_main
>   {
>   	int fd, gt;
> +	struct drm_xe_engine_class_instance *hwe;
>   
>   	igt_fixture {
>   		fd = drm_open_driver(DRIVER_XE);
> @@ -104,6 +230,11 @@ igt_main
>   		xe_for_each_gt(fd, gt)
>   			test_idle_residency(fd, gt);
>   
> +	igt_describe("Validate idle residency on exec");
> +	igt_subtest("idle-residency-on-exec")
> +		xe_for_each_hw_engine(fd, hwe)
> +			idle_residency_on_exec(fd, hwe);
> +
>   	igt_fixture {
>   		close(fd);
>   	}