[igt-dev] [PATCH i-g-t] igt/gem_measure_ring_size_inflight: Measure smallest inflight ring size

[Antonio Argenziano]

Some tests measure the render's ring size but are actually meant to
measure the smallest across all engines. This patch adds measuring the
smallest size in gem_measure_ring_size_inflight() given the appropriate
parameter.

Suggested-by: Chris Wilson <chris at chris-wilson.co.uk>
Signed-off-by: Antonio Argenziano <antonio.argenziano at intel.com>
Cc: Chris Wilson <chris at chris-wilson.co.uk>
---
 lib/i915/gem_ring.c      | 51 ++++++++++++++++++++++++++++++++++--------------
 lib/i915/gem_ring.h      |  3 +++
 tests/gem_busy.c         |  2 +-
 tests/gem_exec_await.c   |  2 +-
 tests/gem_exec_fence.c   |  2 +-
 tests/gem_exec_latency.c |  2 +-
 tests/gem_ringfill.c     |  2 +-
 7 files changed, 44 insertions(+), 20 deletions(-)

diff --git a/lib/i915/gem_ring.c b/lib/i915/gem_ring.c
index 7326673a..df379f1a 100644
--- a/lib/i915/gem_ring.c
+++ b/lib/i915/gem_ring.c
@@ -30,27 +30,14 @@
 #include "drmtest.h"
 #include "ioctl_wrappers.h"
 #include "igt_dummyload.h"
+#include "igt_gt.h"
 
 static void alarm_handler(int sig)
 {
 }
 
-/**
- * gem_measure_ring_inflight:
- * @fd: open i915 drm file descriptor
- * @engine: execbuf engine flag
- * @flags: flags to affect measurement:
- *		- MEASURE_RING_NEW_CTX: use a new context to account for the space
- *		  used by the lrc init.
- *
- * This function calculates the maximum number of batches that can be inserted
- * at the same time in the ring on the selected engine.
- *
- * Returns:
- * Number of batches that fit in the ring
- */
 unsigned int
-gem_measure_ring_inflight(int fd, unsigned int engine, enum measure_ring_flags flags)
+__gem_measure_ring_inflight(int fd, unsigned int engine, enum measure_ring_flags flags)
 {
 	struct sigaction old_sa, sa = { .sa_handler = alarm_handler };
 	struct drm_i915_gem_exec_object2 obj[2];
@@ -115,3 +102,37 @@ gem_measure_ring_inflight(int fd, unsigned int engine, enum measure_ring_flags f
 
 	return count;
 }
+
+/**
+ * gem_measure_ring_inflight:
+ * @fd: open i915 drm file descriptor
+ * @engine: execbuf engine flag. Use '~0u' to get the minimum size across
+ *		    all physical engines.
+ * @flags: flags to affect measurement:
+ *		- MEASURE_RING_NEW_CTX: use a new context to account for the space
+ *		  used by the lrc init.
+ *
+ * This function calculates the maximum number of batches that can be inserted
+ * at the same time in the ring on the selected engine.
+ *
+ * Returns:
+ * Number of batches that fit in the ring
+ */
+unsigned int
+gem_measure_ring_inflight(int fd, unsigned int engine, enum measure_ring_flags flags)
+{
+	if (engine == ~0u) { /* Find minimum ring size across all engines */
+		unsigned int global_min = ~0u;
+
+		for_each_physical_engine(fd, engine) {
+			unsigned int engine_min = __gem_measure_ring_inflight(fd, engine, flags);
+
+			if (engine_min < global_min)
+				global_min = engine_min;
+		}
+
+		return global_min;
+	}
+
+	return __gem_measure_ring_inflight(fd, engine, flags);
+}
diff --git a/lib/i915/gem_ring.h b/lib/i915/gem_ring.h
index c69adce0..9fbce59e 100644
--- a/lib/i915/gem_ring.h
+++ b/lib/i915/gem_ring.h
@@ -30,6 +30,9 @@ enum measure_ring_flags {
 	MEASURE_RING_NEW_CTX = 1
 };
 
+unsigned int
+__gem_measure_ring_inflight(int fd, unsigned int engine, enum measure_ring_flags flags);
+
 unsigned int
 gem_measure_ring_inflight(int fd, unsigned int engine, enum measure_ring_flags flags);
 
diff --git a/tests/gem_busy.c b/tests/gem_busy.c
index fcff51a2..0460877e 100644
--- a/tests/gem_busy.c
+++ b/tests/gem_busy.c
@@ -301,7 +301,7 @@ static void xchg_u32(void *array, unsigned i, unsigned j)
 static void close_race(int fd)
 {
 	const unsigned int ncpus = sysconf(_SC_NPROCESSORS_ONLN);
-	const unsigned int nhandles = gem_measure_ring_inflight(fd, 0, 0) / 2;
+	const unsigned int nhandles = gem_measure_ring_inflight(fd, ~0u, 0) / 2;
 	unsigned int engines[16], nengine;
 	unsigned long *control;
 	uint32_t *handles;
diff --git a/tests/gem_exec_await.c b/tests/gem_exec_await.c
index 2ff180b0..255e0400 100644
--- a/tests/gem_exec_await.c
+++ b/tests/gem_exec_await.c
@@ -234,7 +234,7 @@ igt_main
 		igt_require_gem(device);
 		gem_submission_print_method(device);
 
-		ring_size = gem_measure_ring_inflight(device, 0, 0) - 10;
+		ring_size = gem_measure_ring_inflight(device, ~0u, 0) - 10;
 		if (!gem_has_execlists(device))
 			ring_size /= 2;
 		igt_info("Ring size: %d batches\n", ring_size);
diff --git a/tests/gem_exec_fence.c b/tests/gem_exec_fence.c
index 93ed3b9b..45c9eb83 100644
--- a/tests/gem_exec_fence.c
+++ b/tests/gem_exec_fence.c
@@ -1537,7 +1537,7 @@ igt_main
 		long ring_size = 0;
 
 		igt_fixture {
-			ring_size = gem_measure_ring_inflight(i915, 0, 0) - 1;
+			ring_size = gem_measure_ring_inflight(i915, ~0u, 0) - 1;
 			igt_info("Ring size: %ld batches\n", ring_size);
 			igt_require(ring_size);
 
diff --git a/tests/gem_exec_latency.c b/tests/gem_exec_latency.c
index f0e13419..e6bbeb9e 100644
--- a/tests/gem_exec_latency.c
+++ b/tests/gem_exec_latency.c
@@ -363,7 +363,7 @@ igt_main
 
 		gem_submission_print_method(device);
 
-		ring_size = gem_measure_ring_inflight(device, 0, 0);
+		ring_size = gem_measure_ring_inflight(device, ~0u, 0);
 		igt_info("Ring size: %d batches\n", ring_size);
 		igt_require(ring_size > 8);
 		ring_size -= 8; /* leave some spare */
diff --git a/tests/gem_ringfill.c b/tests/gem_ringfill.c
index eea1d403..cd9ae6c8 100644
--- a/tests/gem_ringfill.c
+++ b/tests/gem_ringfill.c
@@ -272,7 +272,7 @@ igt_main
 			master = true;
 		}
 
-		ring_size = gem_measure_ring_inflight(fd, 0, 0);
+		ring_size = gem_measure_ring_inflight(fd, ~0u, 0);
 		igt_info("Ring size: %d batches\n", ring_size);
 		igt_require(ring_size);
 	}
-- 
2.14.2