Re: [PATCH i-g-t v2 11/14] tests/intel/xe_oa: Rewrite enable-disable test

["Dixit, Ashutosh" <ashutosh.dixit@intel.com>]

On Mon, 03 Mar 2025 15:14:59 -0800, Umesh Nerlige Ramappa wrote:
>
> Keep it simple and just check if enable/disable is working correctly
> using the read call and existing uapi.
>
> v2: Drop mmio and use the value returned in read (Ashutosh)

Thanks for changing this.

>
> Signed-off-by: Umesh Nerlige Ramappa <umesh.nerlige.ramappa@intel.com>
> Reviewed-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
> ---
>  tests/intel/xe_oa.c | 140 ++++++++------------------------------------
>  1 file changed, 24 insertions(+), 116 deletions(-)
>
> diff --git a/tests/intel/xe_oa.c b/tests/intel/xe_oa.c
> index 9c10a8fd2..47c4a1fdb 100644
> --- a/tests/intel/xe_oa.c
> +++ b/tests/intel/xe_oa.c
> @@ -2524,145 +2524,53 @@ test_non_zero_reason(const struct drm_xe_engine_class_instance *hwe, size_t oa_b
>  static void
>  test_enable_disable(const struct drm_xe_engine_class_instance *hwe)
>  {
> -	/* ~5 micro second period */
> -	int oa_exponent = max_oa_exponent_for_period_lte(5000);
> -	uint64_t oa_period = oa_exponent_to_ns(oa_exponent);
> +	uint32_t num_reports = 5;
>	struct intel_xe_perf_metric_set *test_set = metric_set(hwe);
>	uint64_t fmt = test_set->perf_oa_format;
>	uint64_t properties[] = {
>		DRM_XE_OA_PROPERTY_OA_UNIT_ID, 0,
> -
> -		/* Include OA reports in samples */
>		DRM_XE_OA_PROPERTY_SAMPLE_OA, true,
> -
> -		/* OA unit configuration */
>		DRM_XE_OA_PROPERTY_OA_METRIC_SET, test_set->perf_oa_metrics_set,
>		DRM_XE_OA_PROPERTY_OA_FORMAT, __ff(fmt),
> -		DRM_XE_OA_PROPERTY_OA_PERIOD_EXPONENT, oa_exponent,
> +		DRM_XE_OA_PROPERTY_OA_PERIOD_EXPONENT, oa_exponent_default,
>		DRM_XE_OA_PROPERTY_OA_DISABLED, true,
>		DRM_XE_OA_PROPERTY_OA_ENGINE_INSTANCE, hwe->engine_instance,
> +		DRM_XE_OA_PROPERTY_WAIT_NUM_REPORTS, num_reports,
>	};
>	struct intel_xe_oa_open_prop param = {
>		.num_properties = ARRAY_SIZE(properties) / 2,
>		.properties_ptr = to_user_pointer(properties),
>	};
> -	size_t report_size = get_oa_format(fmt).size;
> -	int buf_size = 65536 * report_size;
> -	uint8_t *buf = malloc(buf_size);
> -	int n_full_oa_reports = default_oa_buffer_size / report_size;
> -	uint64_t fill_duration = n_full_oa_reports * oa_period;
> -	uint32_t *last_periodic_report = malloc(report_size);
> -
> -	load_helper_init();
> -	load_helper_run(HIGH);
> +	size_t format_size = get_oa_format(fmt).size;
> +	uint8_t buf[num_reports * format_size];
> +	struct pollfd pollfd;
> +	int ret;
>
>	stream_fd = __perf_open(drm_fd, &param, true /* prevent_pm */);
>          set_fd_flags(stream_fd, O_CLOEXEC);

Doesn't make a difference to the test, but to reduce confusion, I'm
wondering if we should change this to 'O_CLOEXEC | O_NONBLOCK' since we
have introduced poll() here?

Also, there seem to be spaces here rather than tabs.

> -	for (int i = 0; i < 5; i++) {
> -		int len;
> -		uint32_t n_periodic_reports;
> -		uint64_t first_timestamp = 0, last_timestamp = 0;
> -		u32 oa_status;
> -
> -		/* Giving enough time for an overflow might help catch whether
> -		 * the OA unit has been enabled even if the driver might at
> -		 * least avoid copying reports while disabled.
> -		 */
> -		nanosleep(&(struct timespec){ .tv_sec = 0,
> -					      .tv_nsec = fill_duration * 1.25 },
> -			  NULL);
> -
> -		while ((len = read(stream_fd, buf, buf_size)) == -1 &&
> -		       (errno == EINTR || errno == EIO))
> -			;
> -
> -		igt_assert_eq(len, -1);
> -		igt_assert_eq(errno, EINVAL);
> -
> -		do_ioctl(stream_fd, DRM_XE_OBSERVATION_IOCTL_ENABLE, 0);
> -
> -		nanosleep(&(struct timespec){ .tv_sec = 0,
> -					      .tv_nsec = fill_duration / 2 },
> -			NULL);
> -
> -		n_periodic_reports = 0;
> -
> -		/* Because of the race condition between notification of new
> -		 * reports and reports landing in memory, we need to rely on
> -		 * timestamps to figure whether we've read enough of them.
> -		 */
> -		while (((last_timestamp - first_timestamp) * oa_period) < (fill_duration / 2)) {
> -
> -			while ((len = read(stream_fd, buf, buf_size)) == -1 && errno == EINTR)
> -				;
> -			if (errno == EIO) {
> -				oa_status = get_stream_status(stream_fd);
> -				igt_debug("oa_status %#x\n", oa_status);
> -				igt_assert(!(oa_status & DRM_XE_OASTATUS_BUFFER_OVERFLOW));
> -				continue;
> -			}
> -			igt_assert_neq(len, -1);
> -
> -			for (int offset = 0; offset < len; offset += report_size) {
> -				uint32_t *report = (void *) (buf + offset);
> -
> -				if (first_timestamp == 0)
> -					first_timestamp = oa_timestamp(report, fmt);
> -				last_timestamp = oa_timestamp(report, fmt);
> -
> -				igt_debug(" > report ts=%"PRIx64""
> -					  " ts_delta_last_periodic=%s%"PRIu64""
> -					  " is_timer=%i ctx_id=0x%8x\n",
> -					  oa_timestamp(report, fmt),
> -					  oa_report_is_periodic(report) ? " " : "*",
> -					  n_periodic_reports > 0 ?  oa_timestamp_delta(report, last_periodic_report, fmt) : 0,
> -					  oa_report_is_periodic(report),
> -					  oa_report_get_ctx_id(report));
> -
> -				if (oa_report_is_periodic(report)) {
> -					memcpy(last_periodic_report, report, report_size);
> -
> -					/* We want to measure only the periodic reports,
> -					 * ctx-switch might inflate the content of the
> -					 * buffer and skew or measurement.
> -					 */
> -					n_periodic_reports++;
> -				}
> -			}
> -		}
> -
> -		do_ioctl(stream_fd, DRM_XE_OBSERVATION_IOCTL_DISABLE, 0);
> -
> -		igt_debug("first ts = %"PRIu64", last ts = %"PRIu64"\n", first_timestamp, last_timestamp);
> -
> -		igt_debug("%f < %zu < %f\n",
> -			  report_size * n_full_oa_reports * 0.45,
> -			  n_periodic_reports * report_size,
> -			  report_size * n_full_oa_reports * 0.55);
> -
> -		igt_assert((n_periodic_reports * report_size) >
> -			   (report_size * n_full_oa_reports * 0.45));
> -		igt_assert((n_periodic_reports * report_size) <
> -			   report_size * n_full_oa_reports * 0.55);
> -
> +	errno = 0;
> +	ret = read(stream_fd, buf, sizeof(buf));
> +	igt_assert_eq(ret, -1);
> +	igt_assert_eq(errno, EINVAL);
>
> -		/* It's considered an error to read a stream while it's disabled
> -		 * since it would block indefinitely...
> -		 */
> -		len = read(stream_fd, buf, buf_size);
> +	do_ioctl(stream_fd, DRM_XE_OBSERVATION_IOCTL_ENABLE, 0);
>
> -		igt_assert_eq(len, -1);
> -		igt_assert_eq(errno, EINVAL);
> -	}
> +	/*
> +	 * Wait for number of reports specified in
> +	 * DRM_XE_OA_PROPERTY_WAIT_NUM_REPORTS
> +	 */
> +	pollfd.fd = stream_fd;
> +	pollfd.events = POLLIN;
> +	poll(&pollfd, 1, -1);
> +	igt_assert(pollfd.revents & POLLIN);
>
> -	free(last_periodic_report);
> -	free(buf);
> +	/* Ensure num_reports can be read */
> +	while ((ret = read(stream_fd, buf, sizeof(buf))) < 0 && errno == EINTR)
> +		;
> +	igt_assert_eq(ret, sizeof(buf));
>
>	__perf_close(stream_fd);
> -
> -	load_helper_stop();
> -	load_helper_fini();
>  }
>
>  /**
> --
> 2.34.1
>