[Intel-gfx] [PATCH i-g-t v6 05/12] tests/perf: remove frequency related changes

Lionel Landwerlin lionel.g.landwerlin at intel.com
Wed Oct 4 11:19:40 UTC 2017


Experience shows that most of the issues we face with periodicity of
the reports produced by the OA unit are related to power management,
not frequency.

Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin at intel.com>
Reviewed-by: Matthew Auld <matthew.auld at intel.com>
---
 tests/perf.c | 141 ++++-------------------------------------------------------
 1 file changed, 9 insertions(+), 132 deletions(-)

diff --git a/tests/perf.c b/tests/perf.c
index 5fe0a332..f256bac3 100644
--- a/tests/perf.c
+++ b/tests/perf.c
@@ -293,12 +293,9 @@ static int card = -1;
 static int n_eus;
 
 static uint64_t test_metric_set_id = UINT64_MAX;
-static uint64_t gt_min_freq_mhz_saved = 0;
-static uint64_t gt_max_freq_mhz_saved = 0;
-static uint64_t gt_min_freq_mhz = 0;
-static uint64_t gt_max_freq_mhz = 0;
 
 static uint64_t timestamp_frequency = 12500000;
+static uint64_t gt_max_freq_mhz = 0;
 static enum drm_i915_oa_format test_oa_format;
 static bool *undefined_a_counters;
 static uint64_t oa_exp_1_millisec;
@@ -402,16 +399,6 @@ sysfs_read(const char *file)
 	return read_u64_file(buf);
 }
 
-static void
-sysfs_write(const char *file, uint64_t val)
-{
-	char buf[512];
-
-	snprintf(buf, sizeof(buf), "/sys/class/drm/card%d/%s", card, file);
-
-	write_u64_file(buf, val);
-}
-
 static char *
 read_debugfs_record(int device, const char *file, const char *key)
 {
@@ -1008,54 +995,6 @@ init_sys_info(void)
 	return try_read_u64_file(buf, &test_metric_set_id);
 }
 
-static void
-gt_frequency_range_save(void)
-{
-	gt_min_freq_mhz_saved = sysfs_read("gt_min_freq_mhz");
-	gt_max_freq_mhz_saved = sysfs_read("gt_max_freq_mhz");
-
-	gt_min_freq_mhz = gt_min_freq_mhz_saved;
-	gt_max_freq_mhz = gt_max_freq_mhz_saved;
-}
-
-static void
-gt_frequency_pin(int gt_freq_mhz)
-{
-	igt_debug("requesting pinned GT freq = %dmhz\n", gt_freq_mhz);
-
-	if (gt_freq_mhz > gt_max_freq_mhz) {
-		sysfs_write("gt_max_freq_mhz", gt_freq_mhz);
-		sysfs_write("gt_min_freq_mhz", gt_freq_mhz);
-	} else {
-		sysfs_write("gt_min_freq_mhz", gt_freq_mhz);
-		sysfs_write("gt_max_freq_mhz", gt_freq_mhz);
-	}
-	gt_min_freq_mhz = gt_freq_mhz;
-	gt_max_freq_mhz = gt_freq_mhz;
-}
-
-static void
-gt_frequency_range_restore(void)
-{
-	igt_debug("restoring GT frequency range: min = %dmhz, max =%dmhz, current: min=%dmhz, max=%dmhz\n",
-		  (int)gt_min_freq_mhz_saved,
-		  (int)gt_max_freq_mhz_saved,
-		  (int)gt_min_freq_mhz,
-		  (int)gt_max_freq_mhz);
-
-	/* Assume current min/max are the same */
-	if (gt_min_freq_mhz_saved > gt_max_freq_mhz) {
-		sysfs_write("gt_max_freq_mhz", gt_max_freq_mhz_saved);
-		sysfs_write("gt_min_freq_mhz", gt_min_freq_mhz_saved);
-	} else {
-		sysfs_write("gt_min_freq_mhz", gt_min_freq_mhz_saved);
-		sysfs_write("gt_max_freq_mhz", gt_max_freq_mhz_saved);
-	}
-
-	gt_min_freq_mhz = gt_min_freq_mhz_saved;
-	gt_max_freq_mhz = gt_max_freq_mhz_saved;
-}
-
 static int
 i915_read_reports_until_timestamp(enum drm_i915_oa_format oa_format,
 				  uint8_t *buf,
@@ -1632,33 +1571,9 @@ test_oa_formats(void)
 }
 
 static void
-test_oa_exponents(int gt_freq_mhz)
+test_oa_exponents(void)
 {
-	uint32_t freq_margin;
-
-	/* This test tries to use the sysfs interface for pinning the GT
-	 * frequency so we have another point of reference for comparing with
-	 * the clock frequency as derived from OA reports.
-	 *
-	 * This test has been finicky to stabilise while the
-	 * gt_min/max_freq_mhz files in sysfs don't seem to be a reliable
-	 * mechanism for fixing the gpu frequency.
-	 *
-	 * Since these unit tests are focused on the OA unit not the ability to
-	 * pin the frequency via sysfs we make the test account for pinning not
-	 * being reliable and read back the current frequency for each
-	 * iteration of this test to take this into account.
-	 */
-	gt_frequency_pin(gt_freq_mhz);
-
-	igt_debug("Testing OA timer exponents with requested GT frequency = %dmhz\n",
-		  gt_freq_mhz);
-
-	/* allow a +- 10% error margin when checking that the frequency
-	 * calculated from the OA reports matches the frequency according to
-	 * sysfs.
-	 */
-	freq_margin = gt_freq_mhz * 0.1;
+	igt_debug("Testing OA timer exponents\n");
 
 	/* It's asking a lot to sample with a 160 nanosecond period and the
 	 * test can fail due to buffer overflows if it wasn't possible to
@@ -1673,7 +1588,6 @@ test_oa_exponents(int gt_freq_mhz)
 		uint32_t clock_delta;
 		uint32_t freq;
 		int n_tested = 0;
-		int n_freq_matches = 0;
 
 		/* The exponent is effectively selecting a bit in the timestamp
 		 * to trigger reports on and so in practice we expect the raw
@@ -1683,15 +1597,10 @@ test_oa_exponents(int gt_freq_mhz)
 		expected_timestamp_delta = 2 << i;
 
 		for (int j = 0; n_tested < 10 && j < 100; j++) {
-			int gt_freq_mhz_0, gt_freq_mhz_1;
 			uint32_t ticks0, ticks1;
 
-			gt_freq_mhz_0 = sysfs_read("gt_act_freq_mhz");
-
-			igt_debug("ITER %d: testing OA exponent %d (period = %"PRIu64"ns) with sysfs GT freq = %dmhz +- %u\n",
-				  j, i,
-				  oa_exponent_to_ns(i),
-				  gt_freq_mhz_0, freq_margin);
+			igt_debug("ITER %d: testing OA exponent %d (period = %"PRIu64"ns)\n",
+				  j, i, oa_exponent_to_ns(i));
 
 			open_and_read_2_oa_reports(test_oa_format,
 						   i, /* exponent */
@@ -1700,16 +1609,6 @@ test_oa_exponents(int gt_freq_mhz)
 						   true); /* timer triggered
 							     reports only */
 
-			gt_freq_mhz_1 = sysfs_read("gt_act_freq_mhz");
-
-			/* If it looks like the frequency has changed according
-			 * to sysfs then skip looking at this pair of reports
-			 */
-			if (gt_freq_mhz_0 != gt_freq_mhz_1) {
-				igt_debug("skipping OA reports pair due to GT frequency change according to sysfs\n");
-				continue;
-			}
-
 			timestamp_delta = oa_report1[1] - oa_report0[1];
 			igt_assert_neq(timestamp_delta, 0);
 
@@ -1732,31 +1631,13 @@ test_oa_exponents(int gt_freq_mhz)
 			igt_debug("ITER %d: time delta = %"PRIu32"(ns) clock delta = %"PRIu32" freq = %"PRIu32"(mhz)\n",
 				  j, time_delta, clock_delta, freq);
 
-                        if (freq < (gt_freq_mhz_1 + freq_margin) &&
-                            freq > (gt_freq_mhz_1 - freq_margin))
-				n_freq_matches++;
-
 			n_tested++;
 		}
 
 		if (n_tested < 10)
 			igt_debug("sysfs frequency pinning too unstable for cross-referencing with OA derived frequency");
 		igt_assert_eq(n_tested, 10);
-
-		igt_debug("number of iterations with expected clock frequency = %d\n",
-			  n_freq_matches);
-
-		/* Don't assert the calculated frequency for extremely short
-		 * durations.
-		 *
-		 * Allow some mismatches since can't be can't be sure about
-		 * frequency changes between sysfs reads.
-		 */
-		if (i > 3)
-			igt_assert(n_freq_matches >= 7);
 	}
-
-	gt_frequency_range_restore();
 }
 
 /* The OA exponent selects a timestamp counter bit to trigger reports on.
@@ -3981,11 +3862,11 @@ igt_main
 
 		igt_require(init_sys_info());
 
-		gt_frequency_range_save();
-
 		write_u64_file("/proc/sys/dev/i915/perf_stream_paranoid", 1);
 		write_u64_file("/proc/sys/dev/i915/oa_max_sample_rate", 100000);
 
+		gt_max_freq_mhz = sysfs_read("gt_boost_freq_mhz");
+
 		render_copy = igt_get_render_copyfunc(devid);
 		igt_require_f(render_copy, "no render-copy function\n");
 	}
@@ -4012,10 +3893,8 @@ igt_main
 		test_invalid_oa_exponent();
 	igt_subtest("low-oa-exponent-permissions")
 		test_low_oa_exponent_permissions();
-	igt_subtest("oa-exponents") {
-		test_oa_exponents(450);
-		test_oa_exponents(550);
-	}
+	igt_subtest("oa-exponents")
+		test_oa_exponents();
 
 	igt_subtest("per-context-mode-unprivileged") {
 		igt_require(IS_HASWELL(devid));
@@ -4081,8 +3960,6 @@ igt_main
 		write_u64_file("/proc/sys/dev/i915/oa_max_sample_rate", 100000);
 		write_u64_file("/proc/sys/dev/i915/perf_stream_paranoid", 1);
 
-		gt_frequency_range_restore();
-
 		close(drm_fd);
 	}
 }
-- 
2.14.2



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