i915/gem_pwrite: Replace exhaustive tests with bounded probes

Our current tests for pwrite do an exhaustive test of each page within
the object in multiple directions to try and trick the page lookup into
flummoxing. This is quite time consuming, so replace those for CI with a
just a randomised, time-bounded check.

Closes: https://gitlab.freedesktop.org/drm/intel/issues/1283
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Acked-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>

1 files changed, 42 insertions, 1 deletions

diff --git a/tests/i915/gem_pwrite.c b/tests/i915/gem_pwrite.c
index 69f823d5..20e9728b 100644
--- a/tests/i915/gem_pwrite.c
+++ b/tests/i915/gem_pwrite.c
@@ -25,7 +25,6 @@
  *
  */
 
-#include "igt.h"
 #include <unistd.h>
 #include <stdlib.h>
 #include <stdint.h>
@@ -37,8 +36,12 @@
 #include <sys/stat.h>
 #include <sys/ioctl.h>
 #include <sys/time.h>
+
 #include "drm.h"
 
+#include "igt.h"
+#include "igt_rand.h"
+
 #define MiB(x) ((x) * 1024 * 1024)
 
 typedef void *(*mmap_fn_t)(int, uint32_t, uint64_t, uint64_t, unsigned int);
@@ -238,6 +241,41 @@ static void test_big_gtt(int fd, int scale, unsigned flags)
 	gem_close(fd, handle);
 }
 
+static void test_random(int fd)
+{
+	uint32_t prng = 0xdeadbeef;
+	unsigned long count;
+	uint32_t handle;
+	uint64_t *map;
+	uint64_t size;
+
+	gem_require_mmap_wc(fd);
+
+	size = min(intel_get_total_ram_mb() / 2,
+		    gem_mappable_aperture_size() + 4096);
+	intel_require_memory(1, size, CHECK_RAM);
+
+	handle = gem_create(fd, size);
+	map = gem_mmap__wc(fd, handle, 0, size, PROT_WRITE);
+
+	count = 0;
+	igt_until_timeout(5) {
+		uint64_t a = hars_petruska_f54_1_random64(&prng) % (size / sizeof(uint64_t));
+		uint64_t x = hars_petruska_f54_1_random64(&prng);
+
+		gem_write(fd, handle, a * sizeof(x), &x, sizeof(x));
+
+		gem_set_domain(fd, handle, I915_GEM_DOMAIN_WC, 0);
+		igt_assert_eq_u64(map[a], x);
+
+		count++;
+	}
+	igt_info("Completed %lu cycles\n", count);
+
+	munmap(map, handle);
+	gem_close(fd, handle);
+}
+
 uint32_t *src, dst;
 uint32_t *src_user, dst_stolen;
 int fd;
@@ -369,6 +407,9 @@ igt_main_args("s:", NULL, help_str, opt_handler, NULL)
 		gem_close(fd, dst_stolen);
 	}
 
+	igt_subtest_f("basic-random")
+		test_random(fd);
+
 	{
 		const struct mode {
 			const char *name;