Re: [PATCH v4 i-g-t] tests/xe_gt_freq: Avoid RPe usage in subtests

[Riana Tauro <riana.tauro@intel.com>]

Hi Vinay

On 7/31/2024 4:31 AM, Vinay Belgaumkar wrote:
> We are seeing several instances where the RPe, which can be altered by
> pcode dynamically, is causing subtests to fail randomly. Instead of relying
> on it, we can use a mid frequency value for these subtests and avoid these
> failures.
> 
> v2: Fix bug in the tolerance function. Remove rpe usage from freq_range*
> as well (Badal). Fix test documentation to reflect change (Riana).
> 
> v3: Actual frequency cannot be guaranteed to follow the requested value
> 
> v4: Handle cases where RPe can be greater than min/cur freq.
> 
> Link: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/2200
> Link: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/2196
> Link: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/2262
> Link: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/2256
> Link: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/2203
> Link: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/2412
Closes?
> 
> Cc: Riana Tauro <riana.tauro@intel.com>
> Cc: Badal Nilawar <badal.nilawar@intel.com>
> Signed-off-by: Vinay Belgaumkar <vinay.belgaumkar@intel.com>
> ---
>   tests/intel/xe_gt_freq.c | 57 ++++++++++++++++++++++++++++------------
>   1 file changed, 40 insertions(+), 17 deletions(-)
> 
> diff --git a/tests/intel/xe_gt_freq.c b/tests/intel/xe_gt_freq.c
> index 93ebb5ed0..c9d59508b 100644
> --- a/tests/intel/xe_gt_freq.c
> +++ b/tests/intel/xe_gt_freq.c
> @@ -26,6 +26,9 @@
>   #include <sys/time.h>
>   
>   #define MAX_N_EXEC_QUEUES 16
> +#define GT_FREQUENCY_MULTIPLIER	50
> +#define GT_FREQUENCY_SCALER	3
> +#define FREQ_UNIT_MHZ	 DIV_ROUND_CLOSEST(GT_FREQUENCY_MULTIPLIER, GT_FREQUENCY_SCALER)
>   
>   /*
>    * Too many intermediate components and steps before freq is adjusted
> @@ -70,9 +73,14 @@ static uint32_t get_freq(int fd, int gt_id, const char *freq_name)
>   	return freq;
>   }
>   
> -static uint32_t rpe(int fd, int gt_id)
> +static bool within_expected_range(uint32_t freq, uint32_t val)
>   {
> -	return get_freq(fd, gt_id, "rpe");
> +	/*
> +	 * GT Frequencies are requested at units of 16.66 Mhz, so allow
> +	 * that tolerance.
> +	 */
> +	return (freq <= val + FREQ_UNIT_MHZ) &&
> +		(freq >= val - FREQ_UNIT_MHZ);
>   }
>   
>   static uint32_t get_throttle(int fd, int gt_id, const char *throttle_file)
> @@ -128,6 +136,8 @@ static void test_freq_basic_api(int fd, int gt_id)
>   {
>   	uint32_t rpn = get_freq(fd, gt_id, "rpn");
>   	uint32_t rp0 = get_freq(fd, gt_id, "rp0");
> +	uint32_t rpmid = (rp0 + rpn) / 2;
> +	uint32_t min_freq, max_freq;
>   
>   	/*
>   	 * Negative bound tests
> @@ -142,16 +152,19 @@ static void test_freq_basic_api(int fd, int gt_id)
>   	/* Assert min requests are respected from rp0 to rpn */
>   	igt_assert(set_freq(fd, gt_id, "min", rp0) > 0);
>   	igt_assert(get_freq(fd, gt_id, "min") == rp0);
> -	igt_assert(set_freq(fd, gt_id, "min", rpe(fd, gt_id)) > 0);
> -	igt_assert(get_freq(fd, gt_id, "min") == rpe(fd, gt_id));
> +	igt_assert(set_freq(fd, gt_id, "min", rpmid) > 0);
> +	min_freq = get_freq(fd, gt_id, "min");
> +	/* SLPC can set min higher than rpmid - as it follows RPe */
> +	igt_assert(min_freq >= (rpmid - FREQ_UNIT_MHZ));
>   	igt_assert(set_freq(fd, gt_id, "min", rpn) > 0);
>   	igt_assert(get_freq(fd, gt_id, "min") == rpn);
>   
>   	/* Assert max requests are respected from rpn to rp0 */
>   	igt_assert(set_freq(fd, gt_id, "max", rpn) > 0);
>   	igt_assert(get_freq(fd, gt_id, "max") == rpn);
> -	igt_assert(set_freq(fd, gt_id, "max", rpe(fd, gt_id)) > 0);
> -	igt_assert(get_freq(fd, gt_id, "max") == rpe(fd, gt_id));
> +	igt_assert(set_freq(fd, gt_id, "max", rpmid) > 0);
> +	max_freq = get_freq(fd, gt_id, "max");
> +	igt_assert(within_expected_range(max_freq, rpmid));
>   	igt_assert(set_freq(fd, gt_id, "max", rp0) > 0);
>   	igt_assert(get_freq(fd, gt_id, "max") == rp0);
>   }
> @@ -168,13 +181,16 @@ static void test_freq_fixed(int fd, int gt_id, bool gt_idle)
>   {
>   	uint32_t rpn = get_freq(fd, gt_id, "rpn");
>   	uint32_t rp0 = get_freq(fd, gt_id, "rp0");
> +	uint32_t rpmid = (rp0 + rpn) / 2;
> +	uint32_t cur_freq, act_freq;
>   
>   	igt_debug("Starting testing fixed request\n");
>   
>   	/*
>   	 * For Fixed freq we need to set both min and max to the desired value
>   	 * Then we check if hardware is actually operating at the desired freq
> -	 * And let's do this for all the 3 known Render Performance (RP) values.
> +	 * And let's do this for all the 2 known Render Performance (RP) values
> +	 * RP0 and RPn and something in between.
>   	 */
>   	igt_assert(set_freq(fd, gt_id, "min", rpn) > 0);
>   	igt_assert(set_freq(fd, gt_id, "max", rpn) > 0);
> @@ -190,17 +206,20 @@ static void test_freq_fixed(int fd, int gt_id, bool gt_idle)
>   		igt_assert(get_freq(fd, gt_id, "act") == rpn);
>   	}
>   
> -	igt_assert(set_freq(fd, gt_id, "min", rpe(fd, gt_id)) > 0);
> -	igt_assert(set_freq(fd, gt_id, "max", rpe(fd, gt_id)) > 0);
> +	igt_assert(set_freq(fd, gt_id, "min", rpmid) > 0);
> +	igt_assert(set_freq(fd, gt_id, "max", rpmid) > 0);
>   	usleep(ACT_FREQ_LATENCY_US);
> -	igt_assert(get_freq(fd, gt_id, "cur") == rpe(fd, gt_id));
> +	cur_freq = get_freq(fd, gt_id, "cur");
> +	/* If rpmid is around RPe, we could see SLPC follow it */
> +	igt_assert(cur_freq >= (rpmid - FREQ_UNIT_MHZ));
>   
>   	if (gt_idle) {
>   		igt_assert_f(igt_wait(xe_is_gt_in_c6(fd, gt_id), 1000, 10),
>   			     "GT %d should be in C6\n", gt_id);
>   		igt_assert(get_freq(fd, gt_id, "act") == 0);
>   	} else {
> -		igt_assert(get_freq(fd, gt_id, "act") == rpe(fd, gt_id));
> +		act_freq = get_freq(fd, gt_id, "act");
> +		igt_assert(act_freq <= cur_freq + FREQ_UNIT_MHZ);
Can actual frequency be below the expected range of requested?

Thanks,
Riana
>   	}
>   
>   	igt_assert(set_freq(fd, gt_id, "min", rp0) > 0);
> @@ -232,15 +251,17 @@ static void test_freq_fixed(int fd, int gt_id, bool gt_idle)
>   static void test_freq_range(int fd, int gt_id, bool gt_idle)
>   {
>   	uint32_t rpn = get_freq(fd, gt_id, "rpn");
> +	uint32_t rp0 = get_freq(fd, gt_id, "rp0");
> +	uint32_t rpmid = (rp0 + rpn) / 2;
>   	uint32_t cur, act;
>   
>   	igt_debug("Starting testing range request\n");
>   
>   	igt_assert(set_freq(fd, gt_id, "min", rpn) > 0);
> -	igt_assert(set_freq(fd, gt_id, "max", rpe(fd, gt_id)) > 0);
> +	igt_assert(set_freq(fd, gt_id, "max", rpmid) > 0);
>   	usleep(ACT_FREQ_LATENCY_US);
>   	cur = get_freq(fd, gt_id, "cur");
> -	igt_assert(rpn <= cur && cur <= rpe(fd, gt_id));
> +	igt_assert(rpn <= cur && cur <= rpmid + FREQ_UNIT_MHZ);
>   
>   	if (gt_idle) {
>   		igt_assert_f(igt_wait(xe_is_gt_in_c6(fd, gt_id), 1000, 10),
> @@ -248,7 +269,7 @@ static void test_freq_range(int fd, int gt_id, bool gt_idle)
>   		igt_assert(get_freq(fd, gt_id, "act") == 0);
>   	} else {
>   		act = get_freq(fd, gt_id, "act");
> -		igt_assert(rpn <= act && act <= rpe(fd, gt_id));
> +		igt_assert((rpn <= act) && (act <= cur + FREQ_UNIT_MHZ));
>   	}
>   
>   	igt_debug("Finished testing range request\n");
> @@ -262,17 +283,19 @@ static void test_freq_range(int fd, int gt_id, bool gt_idle)
>   static void test_freq_low_max(int fd, int gt_id)
>   {
>   	uint32_t rpn = get_freq(fd, gt_id, "rpn");
> +	uint32_t rp0 = get_freq(fd, gt_id, "rp0");
> +	uint32_t rpmid = (rp0 + rpn) / 2;
>   
>   	/*
>   	 *  When max request < min request, max is ignored and min works like
>   	 * a fixed one. Let's assert this assumption
>   	 */
> -	igt_assert(set_freq(fd, gt_id, "min", rpe(fd, gt_id)) > 0);
> +	igt_assert(set_freq(fd, gt_id, "min", rpmid) > 0);
>   	igt_assert(set_freq(fd, gt_id, "max", rpn) > 0);
>   	usleep(ACT_FREQ_LATENCY_US);
>   
> -	/* Refresh value of rpe, pcode could have adjusted it */
> -	igt_assert(get_freq(fd, gt_id, "cur") == rpe(fd, gt_id));
> +	/* Cur freq will follow RPe, which could be higher than min freq */
> +	igt_assert(get_freq(fd, gt_id, "cur") >= (rpmid - FREQ_UNIT_MHZ));
>   }
>   
>   /**