The testcase added here, stimulates this scenario where a high priority
request is sent while another process keeps submitting requests and
filling its ringbuffer.
>From RFC (Chris):
- Use two FDs, one for each priority submission.
- Move from gem_ringfill to gem_exec_schedule.
- Bound processes to same cpu and wake with signals.
Cc: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Antonio Argenziano <antonio.argenziano@xxxxxxxxx>
---
tests/gem_exec_schedule.c | 113 +++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 112 insertions(+), 1 deletion(-)
diff --git a/tests/gem_exec_schedule.c b/tests/gem_exec_schedule.c
index f2847863..476626e6 100644
--- a/tests/gem_exec_schedule.c
+++ b/tests/gem_exec_schedule.c
@@ -21,7 +21,12 @@
* IN THE SOFTWARE.
*/
+#define _GNU_SOURCE
+#include <sched.h>
+#include <signal.h>
+
#include <sys/poll.h>
+#include <sys/ioctl.h>
#include "igt.h"
#include "igt_vgem.h"
@@ -39,6 +44,15 @@
IGT_TEST_DESCRIPTION("Check that we can control the order of execution");
+static void alarm_handler(int sig)
+{
+}
+
+static int __execbuf(int fd, struct drm_i915_gem_execbuffer2 *execbuf)
+{
+ return ioctl(fd, DRM_IOCTL_I915_GEM_EXECBUFFER2, execbuf);
+}
+
static int __ctx_set_priority(int fd, uint32_t ctx, int prio)
{
struct local_i915_gem_context_param param;
@@ -659,6 +673,95 @@ static bool has_scheduler(int fd)
return has > 0;
}
+static void bind_to_cpu(int cpu)
+{
+ const int ncpus = sysconf(_SC_NPROCESSORS_ONLN);
+ cpu_set_t allowed;
+
+ CPU_ZERO(&allowed);
+ CPU_SET(cpu % ncpus, &allowed);
+ igt_assert(sched_setaffinity(getpid(), sizeof(cpu_set_t), &allowed) == 0);
+}
+
+static void setup_timer(int timeout)
+{
+ struct itimerval itv;
+ struct sigaction sa = { .sa_handler = alarm_handler };
+
+ sigaction(SIGALRM, &sa, NULL);
+ itv.it_interval.tv_sec = 0;
+ itv.it_interval.tv_usec = 100;
+ itv.it_value.tv_sec = 0;
+ itv.it_value.tv_usec = timeout * 1000;
+ setitimer(ITIMER_REAL, &itv, NULL);
+}
+
+/*
+ * This test checks that is possible for a high priority request to trigger a
+ * preemption if another context has filled its ringbuffer.
+ * The aim of the test is to make sure that high priority requests cannot be
+ * stalled by low priority tasks.
+ * */
+static void preempt_while_ringbuffer_full(int fd, uint32_t engine)
+{
+ uint32_t hp_fd;
+ uint32_t hp_ctx, lp_ctx;
+ struct drm_i915_gem_exec_object2 obj, hp_obj;
+ struct drm_i915_gem_execbuffer2 execbuf;
+
+ const unsigned timeout = 10; /*ms*/
+ const uint32_t bbe = MI_BATCH_BUFFER_END;
+
+ hp_fd = drm_open_driver(DRIVER_INTEL);
+
+ memset(&execbuf, 0, sizeof(execbuf));
+ memset(&obj, 0, sizeof(obj));
+ memset(&hp_obj, 0, sizeof(hp_obj));
+
+ lp_ctx = gem_context_create(fd);
+ ctx_set_priority(fd, lp_ctx, -MAX_PRIO);
+
+ hp_ctx = gem_context_create(hp_fd);
+ ctx_set_priority(hp_fd, hp_ctx, MAX_PRIO);
+
+ hp_obj.handle = gem_create(fd, 4096);
+ gem_write(fd, hp_obj.handle, 0, &bbe, sizeof(bbe));
+
+ obj.handle = gem_create(fd, 4096);
+ gem_write(fd, obj.handle, 0, &bbe, sizeof(bbe));
+
+ execbuf.buffers_ptr = to_user_pointer(&obj);
+ execbuf.flags = engine;
+ execbuf.buffer_count = 1;
+ execbuf.rsvd1 = lp_ctx;
+
+ /*Stall execution and fill ring*/
+ igt_spin_batch_new(fd, lp_ctx, engine, 0);
+
+ setup_timer(timeout);
+ while (__execbuf(fd, &execbuf) == 0)
+ ;
+
+ /* steal cpu */
+ bind_to_cpu(0);
+ igt_fork(child, 1) {
+ /* this child is forced to wait for parent to sleep */
+ execbuf.buffers_ptr = to_user_pointer(&hp_obj);
+ execbuf.rsvd1 = hp_ctx;
+ setup_timer(timeout);
+ if (__execbuf(fd, &execbuf)) {
+ igt_assert_f(0, "Failed High priority submission.\n");
+ igt_terminate_spin_batches();
+ }
+ }
+
+ /* process sleeps waiting for space to free, releasing child */
+ setup_timer(2*timeout);
+ __execbuf(fd, &execbuf);
+ igt_terminate_spin_batches();
+ igt_waitchildren();
+}
+
igt_main
{
const struct intel_execution_engine *e;
@@ -669,7 +772,7 @@ igt_main
igt_fixture {
fd = drm_open_driver_master(DRIVER_INTEL);
igt_require_gem(fd);
- gem_require_mmap_wc(fd);
+ //gem_require_mmap_wc(fd);
igt_fork_hang_detector(fd);
}
@@ -731,6 +834,14 @@ igt_main
}
}
+ igt_subtest_group {
+ for (e = intel_execution_engines; e->name; e++) {
+ igt_subtest_f("preempt-while-full-%s", e->name) {
+ preempt_while_ringbuffer_full(fd, e->exec_id | e->flags);
+ }
+ }
+ }
+
igt_fixture {
igt_stop_hang_detector();
close(fd);
--
2.14.1
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