[igt-dev] [PATCH i-g-t v2 1/2] tests/intel/xe_guc_pc: Add freq-power test

[Kamil Konieczny]

Hi Riana,

On 2023-09-21 at 14:25:07 +0530, Riana Tauro wrote:
> An assumption is that at lower frequencies,
> not only do we run slower, but we save power compared to
> higher frequencies.
> 
> This test runs a spinner and sets the min and max frequencies
> to rp0 and rpn respectively. It then checks if power consumed
> at lower frequencies is lesser than higher frequencies.
> 
> v2: Remove Run Type
>     change test name (Kamil)
>     change test documentation and comments (Vinay)
> 
> Signed-off-by: Riana Tauro <riana.tauro at intel.com>
> Reviewed-by: Vinay Belgaumkar <vinay.belgaumkar at intel.com>
> ---
>  tests/intel/xe_guc_pc.c | 88 +++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 88 insertions(+)
> 
> diff --git a/tests/intel/xe_guc_pc.c b/tests/intel/xe_guc_pc.c
> index 0327d8e0e..2b3d08fcb 100644
> --- a/tests/intel/xe_guc_pc.c
> +++ b/tests/intel/xe_guc_pc.c
> @@ -13,6 +13,7 @@
>  
>  #include "igt.h"
>  #include "lib/igt_syncobj.h"
> +#include "igt_power.h"
>  #include "igt_sysfs.h"
>  
>  #include "xe_drm.h"
> @@ -382,6 +383,82 @@ static void test_reset(int fd, int gt_id, int cycles)
>  	}
>  }
>  
> +static int cmp_u64(const void *a, const void *b)
> +{
> +	return (*(u64 *)a - *(u64 *)b);
> +}
> +
> +static uint64_t measure_power(int fd, struct igt_power *gpu)
> +{
> +	struct power_sample sample[2];
> +	uint64_t power[5];
> +
> +	for (int i = 0; i < 5; i++) {
> +		igt_power_get_energy(gpu, &sample[0]);
> +		usleep(10000); /* 10 ms */
> +		igt_power_get_energy(gpu, &sample[1]);
> +
> +		power[i] = igt_power_get_mW(gpu, &sample[0], &sample[1]);
> +	}
> +	/* Sort in ascending order and use a triangular filter */
> +	qsort(power, 5, sizeof(*power), cmp_u64);
> +	return DIV_ROUND_UP(power[1] + 2 * power[2] + power[3], 4);
> +}
> +
> +/**
> + * SUBTEST: freq-power
> + * Description: Validates power consumed at higher frequencies is more than
> + *              power consumed at lower frequencies.
> + */
> +static void test_freq_power(int fd, int gt_id, struct drm_xe_engine_class_instance *hwe)
> +{
> +	uint32_t rp0, rpn, vm;
> +	uint64_t ahnd;
> +	struct igt_power gpu;
> +	struct {
> +		uint64_t power;
> +		uint32_t freq;
> +	} min, max;
> +	igt_spin_t *spin;
> +
> +	/* Run for engines belonging to the gt */
> +	if (gt_id != hwe->gt_id)
> +		return;
> +
> +	igt_power_open(fd, &gpu, "gpu");
> +
> +	rpn = get_freq(fd, gt_id, "rpn");
> +	rp0 = get_freq(fd, gt_id, "rp0");
> +
> +	vm = xe_vm_create(fd, 0, 0);
> +	ahnd = intel_allocator_open(fd, vm, INTEL_ALLOCATOR_RELOC);
> +	spin = igt_spin_new(fd, .ahnd = ahnd, .vm = vm, .hwe = hwe);
> +
> +	igt_assert(set_freq(fd, gt_id, "min", rpn) > 0);

May we not assert here? Use if-else? Or maybe assert if we can
write min into min before xe_vm_create?

> +	igt_assert(set_freq(fd, gt_id, "max", rpn) > 0);
> +	min.freq = get_freq(fd, gt_id, "act");
> +	min.power = measure_power(fd, &gpu);
> +
> +	igt_assert(set_freq(fd, gt_id, "min", rp0) > 0);
> +	igt_assert(set_freq(fd, gt_id, "max", rp0) > 0);

Should we write max before min?

> +	max.freq = get_freq(fd, gt_id, "act");
> +	max.power = measure_power(fd, &gpu);
> +
> +	igt_info("Engine %s:%d  min:%lumW @ %uMHz, max:%lumW @ %uMHz\n",
> +		 xe_engine_class_string(hwe->engine_class), hwe->engine_instance,
> +		 min.power, min.freq, max.power, max.freq);
> +
> +	igt_spin_free(fd, spin);
> +	put_ahnd(ahnd);
> +	xe_vm_destroy(fd, vm);
> +	igt_power_close(&gpu);

You should restore min and max value before assert.
Btw before any assert we should restore old values.

Regards,
Kamil

> +
> +	/* power at max_freq should be at least 10% greater than power at min_freq */
> +	igt_assert_f((11 * min.power < 10 * max.power),
> +		     "%s:%d did not conserve power when setting lower frequency!\n",
> +		     xe_engine_class_string(hwe->engine_class), hwe->engine_instance);
> +}
> +
>  igt_main
>  {
>  	struct drm_xe_engine_class_instance *hwe;
> @@ -472,6 +549,17 @@ igt_main
>  		}
>  	}
>  
> +	igt_describe("Validate more power is consumed at higher frequencies");
> +	igt_subtest("freq-power") {
> +		/* FIXME: Remove skip once hwmon is added */
> +		igt_skip_on(xe_has_vram(fd));
> +		xe_for_each_gt(fd, gt) {
> +			xe_for_each_hw_engine(fd, hwe) {
> +				test_freq_power(fd, gt, hwe);
> +			}
> +		}
> +	}
> +
>  	igt_fixture {
>  		xe_for_each_gt(fd, gt) {
>  			set_freq(fd, gt, "min", stash_min);
> -- 
> 2.40.0
>