[PATCH i-g-t] tests/i915/perf: trybot: Print lost reports on SKL for polling-small-buf

[Umesh Nerlige Ramappa]

On some platforms like SKL a very short oa sampling period sometimes
results in lost reports. The polling-small-buf test fails in some
scenarios on SKL, so print the number of reports.

Signed-off-by: Umesh Nerlige Ramappa <umesh.nerlige.ramappa at intel.com>
---
 tests/i915/perf.c | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/tests/i915/perf.c b/tests/i915/perf.c
index ba477f1c..991f5891 100644
--- a/tests/i915/perf.c
+++ b/tests/i915/perf.c
@@ -2313,13 +2313,15 @@ static void test_polling_small_buf(void)
 		.properties_ptr = to_user_pointer(properties),
 	};
 	uint32_t test_duration = 80 * 1000 * 1000;
-	int sample_size = (sizeof(struct drm_i915_perf_record_header) +
+	struct drm_i915_perf_record_header *header;
+	int sample_size = (sizeof(*header) +
 			   get_oa_format(test_set->perf_oa_format).size);
 	int n_expected_reports = test_duration / oa_exponent_to_ns(oa_exponent);
 	int n_expect_read_bytes = n_expected_reports * sample_size;
 	struct timespec ts = {};
 	int n_bytes_read = 0;
 	uint32_t n_polls = 0;
+	uint32_t n_report_lost = 0;
 
 	stream_fd = __perf_open(drm_fd, &param, true /* prevent_pm */);
 	do_ioctl(stream_fd, I915_PERF_IOCTL_ENABLE, 0);
@@ -2330,20 +2332,26 @@ static void test_polling_small_buf(void)
 		ppoll(&pollfd, 1, NULL, NULL);
 		if (pollfd.revents & POLLIN) {
 			uint8_t buf[1024];
-			int ret;
+			int ret, offset;
 
 			ret = read(stream_fd, buf, sizeof(buf));
 			if (ret >= 0)
 				n_bytes_read += ret;
+
+			for (offset = 0; offset < ret; offset += sample_size) {
+				header = (void *)(buf + offset);
+				if (header->type == DRM_I915_PERF_RECORD_OA_REPORT_LOST)
+					n_report_lost++;
+			}
 		}
 
 		n_polls++;
 	}
 
-	igt_info("Read %d expected %d (%.2f%% of the expected number), polls=%u\n",
+	igt_info("Read %d expected %d (%.2f%% of the expected number), polls=%u, reports lost=%u\n",
 		 n_bytes_read, n_expect_read_bytes,
 		 n_bytes_read * 100.0f / n_expect_read_bytes,
-		 n_polls);
+		 n_polls, n_report_lost);
 
 	__perf_close(stream_fd);
 
-- 
2.20.1