[Intel-gfx] [PATCH] drm/i915/selftests: Show the full scaling curve on failure

[Chris Wilson]

If we detect that the RPS end points do not scale perfectly, take the
time to measure all the in between values as well. We are aborting the
test, so we might as well spend the available time gathering critical
debug information instead.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala at linux.intel.com>
---
 drivers/gpu/drm/i915/gt/selftest_rps.c | 40 ++++++++++++++++++++++++++
 1 file changed, 40 insertions(+)

diff --git a/drivers/gpu/drm/i915/gt/selftest_rps.c b/drivers/gpu/drm/i915/gt/selftest_rps.c
index e0a791eac752..395265121e43 100644
--- a/drivers/gpu/drm/i915/gt/selftest_rps.c
+++ b/drivers/gpu/drm/i915/gt/selftest_rps.c
@@ -484,11 +484,31 @@ int live_rps_frequency_cs(void *arg)
 		if (!scaled_within(max.freq * min.count,
 				   min.freq * max.count,
 				   2, 3)) {
+			int f;
+
 			pr_err("%s: CS did not scale with frequency! scaled min:%llu, max:%llu\n",
 			       engine->name,
 			       max.freq * min.count,
 			       min.freq * max.count);
 			show_pcu_config(rps);
+
+			for (f = min.freq + 1; f <= rps->max_freq; f++) {
+				int act = f;
+				u64 count;
+
+				count = measure_cs_frequency_at(rps, engine, &act);
+				if (act < f)
+					break;
+
+				pr_info("%s: %x:%uMHz: %lluKHz [%d%%]\n",
+					engine->name,
+					act, intel_gpu_freq(rps, act), count,
+					(int)DIV64_U64_ROUND_CLOSEST(100 * min.freq * count,
+								     act * min.count));
+
+				f = act; /* may skip ahead [pcu granularity] */
+			}
+
 			err = -EINVAL;
 		}
 
@@ -593,11 +613,31 @@ int live_rps_frequency_srm(void *arg)
 		if (!scaled_within(max.freq * min.count,
 				   min.freq * max.count,
 				   1, 2)) {
+			int f;
+
 			pr_err("%s: CS did not scale with frequency! scaled min:%llu, max:%llu\n",
 			       engine->name,
 			       max.freq * min.count,
 			       min.freq * max.count);
 			show_pcu_config(rps);
+
+			for (f = min.freq + 1; f <= rps->max_freq; f++) {
+				int act = f;
+				u64 count;
+
+				count = measure_frequency_at(rps, cntr, &act);
+				if (act < f)
+					break;
+
+				pr_info("%s: %x:%uMHz: %lluKHz [%d%%]\n",
+					engine->name,
+					act, intel_gpu_freq(rps, act), count,
+					(int)DIV64_U64_ROUND_CLOSEST(100 * min.freq * count,
+								     act * min.count));
+
+				f = act; /* may skip ahead [pcu granularity] */
+			}
+
 			err = -EINVAL;
 		}
 
-- 
2.20.1