[PATCH i-g-t v6] pm_rps: Changes in waitboost scenario

[Katarzyna Dec <katarzyna.dec@intel.com>]

CI is observing sporadical failures in pm_rps subtests.
There are a couple of reasons. One of them is the fact that
on gen6, gen7 and gen7.5, max frequency (as in the HW limit)
is not set to RP0, but the value obtaind from PCODE (which
may be different from RP0). Thus the test is operating under
wrong assumptions (SOFTMAX == RP0 == BOOST which is simply
not the case). Let's compare current frequency with BOOST
frequency rather than SOFTMAX to get the test behaviour under control.
In boost_freq function I set MAX freq to midium freqency, which ensures
that we for sure reach BOOST frequency. This could help with failures
with boost frequency failing to drop down.
GPU reset needs to be modified so we are not dependent on kernel's low
priority retire worker. Reset method was replaced by igt_force_gpu_reset()
and in reset testcase we make sure that we can recover from hang.

v2: Commit message, simplified waiting for boost to finish, drop
noisy whitespace cleanup.

v3: Removed reading from i915_rps_boost_info debugfs because it not
the same on every kernel. Removed function waiting for boost.
Instead of that I made sure we will reach in boost by setting MAX freq to fmid.

v4: Moved proposal with making test drm master to other patch

v5: Used igt_force_gpu_reset() to reset GPU. Modified "reset" testcase.

v6: Comments changes and update.

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Jeff Mcgee <jeff.mcgee@intel.com>
Cc: Petri Latvala <petri.latvala@intel.com>
Cc: Jani Saarinen <jani.saarinen@intel.com>
Cc: Radoslaw Szwichtenberg <radoslaw.szwichtenberg@intel.com>
Reviewed-by: Radoslaw Szwichtenberg <radoslaw.szwichtenberg@intel.com>
Acked-by: Daniel Vetter <daniel.vetter@intel.com>
Signed-off-by: Katarzyna Dec <katarzyna.dec@intel.com>
---
 tests/pm_rps.c | 67 ++++++++++++++++++++++++++++++++++++----------------------
 1 file changed, 42 insertions(+), 25 deletions(-)

diff --git a/tests/pm_rps.c b/tests/pm_rps.c
index f0455e78..f821c210 100644
--- a/tests/pm_rps.c
+++ b/tests/pm_rps.c
@@ -50,6 +50,7 @@ enum {
 	RP0,
 	RP1,
 	RPn,
+	BOOST,
 	NUMFREQ
 };
 
@@ -60,7 +61,7 @@ struct junk {
 	const char *mode;
 	FILE *filp;
 } stuff[] = {
-	{ "cur", "r", NULL }, { "min", "rb+", NULL }, { "max", "rb+", NULL }, { "RP0", "r", NULL }, { "RP1", "r", NULL }, { "RPn", "r", NULL }, { NULL, NULL, NULL }
+	{ "cur", "r", NULL }, { "min", "rb+", NULL }, { "max", "rb+", NULL }, { "RP0", "r", NULL }, { "RP1", "r", NULL }, { "RPn", "r", NULL }, { "boost", "rb+", NULL }, { NULL, NULL, NULL }
 };
 
 static int readval(FILE *filp)
@@ -167,7 +168,7 @@ static void dump(const int *freqs)
 }
 
 enum load {
-	LOW,
+	LOW = 0,
 	HIGH
 };
 
@@ -185,9 +186,10 @@ static struct load_helper {
 
 static void load_helper_signal_handler(int sig)
 {
-	if (sig == SIGUSR2)
-		lh.load = lh.load == LOW ? HIGH : LOW;
-	else
+	if (sig == SIGUSR2) {
+		lh.load = !lh.load;
+		igt_debug("Switching background load to %s\n", lh.load ? "high" : "low");
+	} else
 		lh.exit = true;
 }
 
@@ -238,6 +240,7 @@ static void load_helper_run(enum load load)
 		return;
 	}
 
+	lh.exit = false;
 	lh.load = load;
 
 	igt_fork_helper(&lh.igt_proc) {
@@ -263,6 +266,8 @@ static void load_helper_run(enum load load)
 		if (intel_gen(lh.devid) >= 6)
 			execbuf.flags = I915_EXEC_BLT;
 
+		igt_debug("Applying %s load...\n", lh.load ? "high" : "low");
+
 		while (!lh.exit) {
 			memset(&object, 0, sizeof(object));
 			object.handle = fences[val%3];
@@ -296,6 +301,12 @@ static void load_helper_run(enum load load)
 		gem_close(drm_fd, fences[0]);
 		gem_close(drm_fd, fences[1]);
 		gem_close(drm_fd, fences[2]);
+
+		/* Idle/boost logic is tide with request requirement.
+		 * Speed up detection of idle state and ensure deboost
+		 * after removing load.
+		 */
+		igt_drop_caches_set(drm_fd, DROP_RETIRE);
 	}
 }
 
@@ -553,38 +564,43 @@ static void stabilize_check(int *out)
 	igt_debug("Waited %d msec to stabilize cur\n", wait);
 }
 
-static void reset_gpu(void)
-{
-	int fd = drm_open_driver(DRIVER_INTEL);
-	igt_post_hang_ring(fd, igt_hang_ring(fd, I915_EXEC_DEFAULT));
-	close(fd);
-}
-
 static void boost_freq(int fd, int *boost_freqs)
 {
 	int64_t timeout = 1;
-	int ring = -1;
 	igt_spin_t *load;
+	unsigned int engine;
+	int fmid = (origfreqs[RPn] + origfreqs[RP0]) / 2;
 
-	load = igt_spin_batch_new(fd, ring, 0);
+	fmid = get_hw_rounded_freq(fmid);
+	/* set max freq to less then boost freq */
+	writeval(stuff[MAX].filp, fmid);
 
+	/* put boost on the same engine as low load */
+	engine = I915_EXEC_RENDER;
+	if (intel_gen(lh.devid) >= 6)
+		engine = I915_EXEC_BLT;
+	load = igt_spin_batch_new(fd, engine, 0);
 	/* Waiting will grant us a boost to maximum */
 	gem_wait(fd, load->handle, &timeout);
 
 	read_freqs(boost_freqs);
 	dump(boost_freqs);
 
+	/* Avoid downlocking till boost request is pending */
+	igt_spin_batch_end(load);
+	gem_sync(fd, load->handle);
 	igt_spin_batch_free(fd, load);
+
+	/* set max freq to original softmax */
+	writeval(stuff[MAX].filp, origfreqs[MAX]);
 }
 
-static void waitboost(bool reset)
+static void waitboost(int fd, bool reset)
 {
 	int pre_freqs[NUMFREQ];
 	int boost_freqs[NUMFREQ];
 	int post_freqs[NUMFREQ];
 
-	int fd = drm_open_driver(DRIVER_INTEL);
-
 	load_helper_run(LOW);
 
 	igt_debug("Apply low load...\n");
@@ -593,7 +609,7 @@ static void waitboost(bool reset)
 
 	if (reset) {
 		igt_debug("Reset gpu...\n");
-		reset_gpu();
+		igt_force_gpu_reset(fd);
 		sleep(1);
 	}
 
@@ -611,10 +627,9 @@ static void waitboost(bool reset)
 	idle_check();
 
 	igt_assert_lt(pre_freqs[CUR], pre_freqs[MAX]);
-	igt_assert_eq(boost_freqs[CUR], boost_freqs[MAX]);
+	igt_assert_eq(boost_freqs[CUR], boost_freqs[BOOST]);
 	igt_assert_lt(post_freqs[CUR], post_freqs[MAX]);
 
-	close(fd);
 }
 
 static void pm_rps_exit_handler(int sig)
@@ -657,7 +672,7 @@ igt_main
 			val = readval(junk->filp);
 			igt_assert(val >= 0);
 			junk++;
-		} while(junk->name != NULL);
+		} while (junk->name != NULL);
 
 		read_freqs(origfreqs);
 
@@ -679,9 +694,11 @@ igt_main
 	}
 
 	igt_subtest("waitboost")
-		waitboost(false);
-
-	igt_subtest("reset")
-		waitboost(true);
+		waitboost(drm_fd, false);
 
+	igt_subtest("reset") {
+		igt_hang_t hang = igt_allow_hang(drm_fd, 0, 0);
+		waitboost(drm_fd, true);
+		igt_disallow_hang(drm_fd, hang);
+	}
 }
-- 
2.13.4

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