Test configurable poll delay in perf OA

index 3794e768..594a42d1 100644
@@ -1969,6 +1969,30 @@ enum drm_i915_perf_property_id {
 	 */
 	DRM_I915_PERF_PROP_HOLD_PREEMPTION,
 
+	/**
+	 * Specifying this pins all contexts to the specified SSEU power
+	 * configuration for the duration of the recording.
+	 *
+	 * This parameter's value is a pointer to a struct
+	 * drm_i915_gem_context_param_sseu.
+	 *
+	 * This property is available in perf revision 4.
+	 */
+	DRM_I915_PERF_PROP_GLOBAL_SSEU,
+
+	/**
+	 * This optional parameter specifies the timer interval in nanoseconds
+	 * at which the i915 driver will check the OA buffer for available data.
+	 * Minimum allowed value is 100 microseconds. A default value is used by
+	 * the driver if this parameter is not specified. Note that a large
+	 * value may reduce cpu consumption during OA perf captures, but it
+	 * would also potentially result in OA buffer overwrite as the captures
+	 * reach end of the OA buffer.
+	 *
+	 * This property is available in perf revision 5.
+	 */
+	DRM_I915_PERF_PROP_POLL_OA_PERIOD,
+
 	DRM_I915_PERF_PROP_MAX /* non-ABI */
 };
 

index 724f6f80..8f6537d6 100644
@@ -234,6 +234,24 @@ get_oa_format(enum drm_i915_oa_format format)
 		return gen8_oa_formats[format];
 }
 
+static char *
+pretty_print_oa_period(uint64_t oa_period_ns)
+{
+	static char result[100];
+	static const char *units[4] = { "ns", "us", "ms", "s" };
+	double val = oa_period_ns;
+	int iter = 0;
+
+	while (iter < (ARRAY_SIZE(units) - 1) &&
+	       val >= 1000.0f) {
+		val /= 1000.0f;
+		iter++;
+	}
+
+	snprintf(result, sizeof(result), "%.3f%s", val, units[iter]);
+	return result;
+}
+
 static void
 __perf_close(int fd)
 {

@@ -1921,15 +1939,9 @@ get_time(void)
  * kernelspace.
  */
 static void
-test_blocking(void)
+test_blocking(uint64_t requested_oa_period, bool set_kernel_hrtimer, uint64_t kernel_hrtimer)
 {
-	/* ~40 milliseconds
-	 *
-	 * Having a period somewhat > sysconf(_SC_CLK_TCK) helps to stop
-	 * scheduling (liable to kick in when we make blocking poll()s/reads)
-	 * from interfering with the test.
-	 */
-	int oa_exponent = max_oa_exponent_for_period_lte(40000000);
+	int oa_exponent = max_oa_exponent_for_period_lte(requested_oa_period);
 	uint64_t oa_period = oa_exponent_to_ns(oa_exponent);
 	uint64_t properties[] = {
 		/* Include OA reports in samples */

@@ -1939,11 +1951,16 @@ test_blocking(void)
 		DRM_I915_PERF_PROP_OA_METRICS_SET, test_set->perf_oa_metrics_set,
 		DRM_I915_PERF_PROP_OA_FORMAT, test_set->perf_oa_format,
 		DRM_I915_PERF_PROP_OA_EXPONENT, oa_exponent,
+
+		/* Kernel configuration (optional) */
+		DRM_I915_PERF_PROP_POLL_OA_PERIOD, kernel_hrtimer,
 	};
 	struct drm_i915_perf_open_param param = {
 		.flags = I915_PERF_FLAG_FD_CLOEXEC |
 			I915_PERF_FLAG_DISABLED,
-		.num_properties = sizeof(properties) / 16,
+		.num_properties = set_kernel_hrtimer ?
+				  NUM_PROPERTIES(properties) :
+				  NUM_PROPERTIES(properties) - 1,
 		.properties_ptr = to_user_pointer(properties),
 	};
 	uint8_t buf[1024 * 1024];

@@ -1965,7 +1982,7 @@ test_blocking(void)
 	 * the knowledge that that the driver uses a 200Hz hrtimer (5ms period)
 	 * to check for data and giving some time to read().
 	 */
-	int min_iterations = (test_duration_ns / (oa_period + 6000000ull));
+	int min_iterations = (test_duration_ns / (oa_period + kernel_hrtimer + kernel_hrtimer / 5));
 
 	int64_t start, end;
 	int n = 0;

@@ -1975,9 +1992,10 @@ test_blocking(void)
 	times(&start_times);
 
 	igt_debug("tick length = %dns, test duration = %"PRIu64"ns, min iter. = %d,"
-		  " estimated max iter. = %d, oa_period = %"PRIu64"ns\n",
+		  " estimated max iter. = %d, oa_period = %s\n",
 		  (int)tick_ns, test_duration_ns,
-		  min_iterations, max_iterations, oa_period);
+		  min_iterations, max_iterations,
+		  pretty_print_oa_period(oa_period));
 
 	/* In the loop we perform blocking polls while the HW is sampling at
 	 * ~25Hz, with the expectation that we spend most of our time blocked

@@ -2052,8 +2070,8 @@ test_blocking(void)
 	user_ns = (end_times.tms_utime - start_times.tms_utime) * tick_ns;
 	kernel_ns = (end_times.tms_stime - start_times.tms_stime) * tick_ns;
 
-	igt_debug("%d blocking reads during test with ~25Hz OA sampling (expect no more than %d)\n",
-		  n, max_iterations);
+	igt_debug("%d blocking reads during test with %lu Hz OA sampling (expect no more than %d)\n",
+		  n, NSEC_PER_SEC / oa_period, max_iterations);
 	igt_debug("%d extra iterations seen, not related to periodic sampling (e.g. context switches)\n",
 		  n_extra_iterations);
 	igt_debug("time in userspace = %"PRIu64"ns (+-%dns) (start utime = %d, end = %d)\n",

@@ -2079,15 +2097,9 @@ test_blocking(void)
 }
 
 static void
-test_polling(void)
+test_polling(uint64_t requested_oa_period, bool set_kernel_hrtimer, uint64_t kernel_hrtimer)
 {
-	/* ~40 milliseconds
-	 *
-	 * Having a period somewhat > sysconf(_SC_CLK_TCK) helps to stop
-	 * scheduling (liable to kick in when we make blocking poll()s/reads)
-	 * from interfering with the test.
-	 */
-	int oa_exponent = max_oa_exponent_for_period_lte(40000000);
+	int oa_exponent = max_oa_exponent_for_period_lte(requested_oa_period);
 	uint64_t oa_period = oa_exponent_to_ns(oa_exponent);
 	uint64_t properties[] = {
 		/* Include OA reports in samples */

@@ -2097,12 +2109,17 @@ test_polling(void)
 		DRM_I915_PERF_PROP_OA_METRICS_SET, test_set->perf_oa_metrics_set,
 		DRM_I915_PERF_PROP_OA_FORMAT, test_set->perf_oa_format,
 		DRM_I915_PERF_PROP_OA_EXPONENT, oa_exponent,
+
+		/* Kernel configuration (optional) */
+		DRM_I915_PERF_PROP_POLL_OA_PERIOD, kernel_hrtimer,
 	};
 	struct drm_i915_perf_open_param param = {
 		.flags = I915_PERF_FLAG_FD_CLOEXEC |
 			I915_PERF_FLAG_DISABLED |
 			I915_PERF_FLAG_FD_NONBLOCK,
-		.num_properties = sizeof(properties) / 16,
+		.num_properties = set_kernel_hrtimer ?
+				  NUM_PROPERTIES(properties) :
+				  NUM_PROPERTIES(properties) - 1,
 		.properties_ptr = to_user_pointer(properties),
 	};
 	uint8_t buf[1024 * 1024];

@@ -2116,15 +2133,16 @@ test_polling(void)
 	int n_extra_iterations = 0;
 
 	/* It's a bit tricky to put a lower limit here, but we expect a
-	 * relatively low latency for seeing reports, while we don't currently
-	 * give any control over this in the api.
+	 * relatively low latency for seeing reports.
 	 *
-	 * We assume a maximum latency of 6 millisecond to deliver a POLLIN and
-	 * read() after a new sample is written (46ms per iteration) considering
-	 * the knowledge that that the driver uses a 200Hz hrtimer (5ms period)
-	 * to check for data and giving some time to read().
+	 * We assume a maximum latency of kernel_hrtimer + some margin
+	 * to deliver a POLLIN and read() after a new sample is
+	 * written (40ms + hrtimer + margin per iteration) considering
+	 * the knowledge that that the driver uses a 200Hz hrtimer
+	 * (5ms period) to check for data and giving some time to
+	 * read().
 	 */
-	int min_iterations = (test_duration_ns / (oa_period + 6000000ull));
+	int min_iterations = (test_duration_ns / (oa_period + (kernel_hrtimer + kernel_hrtimer / 5)));
 	int64_t start, end;
 	int n = 0;
 

@@ -2132,8 +2150,9 @@ test_polling(void)
 
 	times(&start_times);
 
-	igt_debug("tick length = %dns, test duration = %"PRIu64"ns, min iter. = %d, max iter. = %d\n",
-		  (int)tick_ns, test_duration_ns,
+	igt_debug("tick length = %dns, oa period = %s, "
+		  "test duration = %"PRIu64"ns, min iter. = %d, max iter. = %d\n",
+		  (int)tick_ns, pretty_print_oa_period(oa_period), test_duration_ns,
 		  min_iterations, max_iterations);
 
 	/* In the loop we perform blocking polls while the HW is sampling at

@@ -2239,8 +2258,8 @@ test_polling(void)
 	user_ns = (end_times.tms_utime - start_times.tms_utime) * tick_ns;
 	kernel_ns = (end_times.tms_stime - start_times.tms_stime) * tick_ns;
 
-	igt_debug("%d blocking reads during test with ~25Hz OA sampling (expect no more than %d)\n",
-		  n, max_iterations);
+	igt_debug("%d non-blocking reads during test with %lu Hz OA sampling (expect no more than %d)\n",
+		  n, NSEC_PER_SEC / oa_period, max_iterations);
 	igt_debug("%d extra iterations seen, not related to periodic sampling (e.g. context switches)\n",
 		  n_extra_iterations);
 	igt_debug("time in userspace = %"PRIu64"ns (+-%dns) (start utime = %d, end = %d)\n",

@@ -4588,6 +4607,23 @@ test_sysctl_defaults(void)
 	igt_assert_eq(max_freq, 100000);
 }
 
+static int i915_perf_revision(int fd)
+{
+	drm_i915_getparam_t gp;
+	int value = 1, ret;
+
+	gp.param = I915_PARAM_PERF_REVISION;
+	gp.value = &value;
+	ret = igt_ioctl(drm_fd, DRM_IOCTL_I915_GETPARAM, &gp);
+	if (ret == -1) {
+		/* If the param is missing, consider version 1. */
+		igt_assert_eq(errno, EINVAL);
+		return 1;
+	}
+
+	return value;
+}
+
 igt_main
 {
 	igt_fixture {

@@ -4670,11 +4706,43 @@ igt_main
 	igt_subtest("enable-disable")
 		test_enable_disable();
 
-	igt_subtest("blocking")
-		test_blocking();
+	igt_describe("Test blocking read with default hrtimer frequency");
+	igt_subtest("blocking") {
+		test_blocking(40 * 1000 * 1000 /* 40ms oa period */,
+			      false /* set_kernel_hrtimer */,
+			      5 * 1000 * 1000 /* default 5ms/200Hz hrtimer */);
+	}
+
+	igt_describe("Test blocking read with different hrtimer frequencies");
+	igt_subtest("blocking-parameterized") {
+		igt_require(i915_perf_revision(drm_fd) >= 5);
+
+		test_blocking(10 * 1000 * 1000 /* 10ms oa period */,
+			      true /* set_kernel_hrtimer */,
+			      40 * 1000 * 1000 /* default 40ms hrtimer */);
+		test_blocking(500 * 1000 /* 500us oa period */,
+			      true /* set_kernel_hrtimer */,
+			      2 * 1000 * 1000 /* default 2ms hrtimer */);
+	}
 
-	igt_subtest("polling")
-		test_polling();
+	igt_describe("Test polled read with default hrtimer frequency");
+	igt_subtest("polling") {
+		test_polling(40 * 1000 * 1000 /* 40ms oa period */,
+			     false /* set_kernel_hrtimer */,
+			     5 * 1000 * 1000 /* default 5ms/200Hz hrtimer */);
+	}
+
+	igt_describe("Test polled read with different hrtimer frequencies");
+	igt_subtest("polling-parameterized") {
+		igt_require(i915_perf_revision(drm_fd) >= 5);
+
+		test_polling(10 * 1000 * 1000 /* 10ms oa period */,
+			     true /* set_kernel_hrtimer */,
+			     40 * 1000 * 1000 /* default 40ms hrtimer */);
+		test_polling(500 * 1000 /* 500us oa period */,
+			     true /* set_kernel_hrtimer */,
+			     2 * 1000 * 1000 /* default 2ms hrtimer */);
+	}
 
 	igt_subtest("short-reads")
 		test_short_reads();

index 6bbc451e..ca4f13ea 100644
@@ -353,14 +353,31 @@ struct recording_context {
 
 	const char *command_fifo;
 	int command_fifo_fd;
+
+	uint64_t poll_period;
 };
 
+static int
+perf_revision(int drm_fd)
+{
+	drm_i915_getparam_t gp;
+	int value = 1;
+
+	gp.param = I915_PARAM_PERF_REVISION;
+	gp.value = &value;
+	perf_ioctl(drm_fd, DRM_IOCTL_I915_GETPARAM, &gp);
+
+	return value;
+}
+
 static int
 perf_open(struct recording_context *ctx)
 {
 	uint64_t properties[DRM_I915_PERF_PROP_MAX * 2];
 	struct drm_i915_perf_open_param param;
-	int p = 0, stream_fd;
+	int p = 0, stream_fd, revision;
+
+	revision = perf_revision(ctx->drm_fd);
 
 	properties[p++] = DRM_I915_PERF_PROP_SAMPLE_OA;
 	properties[p++] = true;

@@ -374,6 +391,11 @@ perf_open(struct recording_context *ctx)
 	properties[p++] = DRM_I915_PERF_PROP_OA_EXPONENT;
 	properties[p++] = ctx->oa_exponent;
 
+	if (revision >= 4) {
+		properties[p++] = DRM_I915_PERF_PROP_POLL_OA_PERIOD;
+		properties[p++] = ctx->poll_period;
+	}
+
 	memset(&param, 0, sizeof(param));
 	param.flags = 0;
 	param.flags |= I915_PERF_FLAG_FD_CLOEXEC | I915_PERF_FLAG_FD_NONBLOCK;

@@ -720,7 +742,10 @@ usage(const char *name)
 		"                                       (To use with i915-perf-control)\n"
 		"     --output,             -o <path>   Output file (default = i915_perf.record)\n"
 		"     --cpu-clock,          -k <path>   Cpu clock to use for correlations\n"
-		"                                       Values: boot, mono, mono_raw (default = mono)\n",
+		"                                       Values: boot, mono, mono_raw (default = mono)\n"
+		"     --poll-delay          -P <value>  Polling interval in microseconds used by a timer in the driver to query\n"
+		"                                       for OA reports periodically\n"
+		"                                       (default = 5000), Minimum = 100.\n",
 		name);
 }
 

@@ -762,6 +787,7 @@ main(int argc, char *argv[])
 		{"size",                 required_argument, 0, 's'},
 		{"command-fifo",         required_argument, 0, 'f'},
 		{"cpu-clock",            required_argument, 0, 'k'},
+		{"poll-delay",           required_argument, 0, 'P'},
 		{0, 0, 0, 0}
 	};
 	const struct {

@@ -788,9 +814,11 @@ main(int argc, char *argv[])
 
 		.command_fifo = I915_PERF_RECORD_FIFO_PATH,
 		.command_fifo_fd = -1,
+
+		.poll_period = 5 * 1000 * 1000,
 	};
 
-	while ((opt = getopt_long(argc, argv, "hc:p:m:Co:s:f:k:", long_options, NULL)) != -1) {
+	while ((opt = getopt_long(argc, argv, "hc:p:m:Co:s:f:k:P:", long_options, NULL)) != -1) {
 		switch (opt) {
 		case 'h':
 			usage(argv[0]);

@@ -832,6 +860,9 @@ main(int argc, char *argv[])
 			}
 			break;
 		}
+		case 'P':
+			ctx.poll_period = MAX(100, atol(optarg)) * 1000;
+			break;
 		default:
 			fprintf(stderr, "Internal error: "
 				"unexpected getopt value: %d\n", opt);