[igt-dev] [PATCH i-g-t 3/5] i915: Exercise preemption timeout controls in sysfs
Chris Wilson
chris at chris-wilson.co.uk
Wed Mar 11 09:34:46 UTC 2020
We [will] expose various per-engine scheduling controls. One of which,
'preempt_timeout_ms', defines how we wait for a preemption request to be
honoured by the currently executing context. If it fails to relieve the
GPU within the required timeout, the engine is reset and the miscreant
forcibly evicted.
Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
tests/Makefile.sources | 3 +
tests/i915/sysfs_preempt_timeout.c | 311 +++++++++++++++++++++++++++++
tests/intel-ci/blacklist.txt | 1 +
tests/meson.build | 1 +
4 files changed, 316 insertions(+)
create mode 100644 tests/i915/sysfs_preempt_timeout.c
diff --git a/tests/Makefile.sources b/tests/Makefile.sources
index 4ac6e35ca..c1711b336 100644
--- a/tests/Makefile.sources
+++ b/tests/Makefile.sources
@@ -104,6 +104,9 @@ TESTS_progs = \
vgem_slow \
$(NULL)
+TESTS_progs += sysfs_preempt_timeout
+sysfs_preempt_timeout_SOURCES = i915/sysfs_preempt_timeout.c
+
TESTS_progs += gem_bad_reloc
gem_bad_reloc_SOURCES = i915/gem_bad_reloc.c
diff --git a/tests/i915/sysfs_preempt_timeout.c b/tests/i915/sysfs_preempt_timeout.c
new file mode 100644
index 000000000..be1905bcd
--- /dev/null
+++ b/tests/i915/sysfs_preempt_timeout.c
@@ -0,0 +1,311 @@
+/*
+ * Copyright © 2019 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#include <dirent.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <inttypes.h>
+#include <sched.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include "drmtest.h" /* gem_quiescent_gpu()! */
+#include "i915/gem_engine_topology.h"
+#include "igt_dummyload.h"
+#include "igt_sysfs.h"
+#include "ioctl_wrappers.h" /* igt_require_gem()! */
+#include "sw_sync.h"
+
+#include "igt_debugfs.h"
+
+#define ATTR "preempt_timeout_ms"
+#define RESET_TIMEOUT 20 /* milliseconds, at least one jiffie for kworker */
+
+static bool __enable_hangcheck(int dir, bool state)
+{
+ return igt_sysfs_set(dir, "enable_hangcheck", state ? "1" : "0");
+}
+
+static bool enable_hangcheck(int i915, bool state)
+{
+ bool success;
+ int dir;
+
+ dir = igt_sysfs_open_parameters(i915);
+ if (dir < 0) /* no parameters, must be default! */
+ return false;
+
+ success = __enable_hangcheck(dir, state);
+ close(dir);
+
+ return success;
+}
+
+static void set_preempt_timeout(int engine, unsigned int value)
+{
+ unsigned int delay;
+
+ igt_sysfs_printf(engine, ATTR, "%u", value);
+ igt_sysfs_scanf(engine, ATTR, "%u", &delay);
+ igt_assert_eq(delay, value);
+}
+
+static void test_idempotent(int i915, int engine)
+{
+ unsigned int delays[] = { 0, 1, 1000, 1234, 654321 };
+ unsigned int saved;
+
+ /* Quick test that store/show reports the same values */
+
+ igt_assert(igt_sysfs_scanf(engine, ATTR, "%u", &saved) == 1);
+ igt_debug("Initial %s:%u\n", ATTR, saved);
+
+ for (int i = 0; i < ARRAY_SIZE(delays); i++)
+ set_preempt_timeout(engine, delays[i]);
+
+ set_preempt_timeout(engine, saved);
+}
+
+static void test_invalid(int i915, int engine)
+{
+ unsigned int saved, delay;
+
+ /* Quick test that values that are not representable are rejected */
+
+ igt_assert(igt_sysfs_scanf(engine, ATTR, "%u", &saved) == 1);
+ igt_debug("Initial %s:%u\n", ATTR, saved);
+
+ igt_sysfs_printf(engine, ATTR, PRIu64, -1);
+ igt_sysfs_scanf(engine, ATTR, "%u", &delay);
+ igt_assert_eq(delay, saved);
+
+ igt_sysfs_printf(engine, ATTR, "%d", -1);
+ igt_sysfs_scanf(engine, ATTR, "%u", &delay);
+ igt_assert_eq(delay, saved);
+
+ igt_sysfs_printf(engine, ATTR, PRIu64, 40ull << 32);
+ igt_sysfs_scanf(engine, ATTR, "%u", &delay);
+ igt_assert_eq(delay, saved);
+}
+
+static void set_unbannable(int i915, uint32_t ctx)
+{
+ struct drm_i915_gem_context_param p = {
+ .ctx_id = ctx,
+ .param = I915_CONTEXT_PARAM_BANNABLE,
+ };
+
+ gem_context_set_param(i915, &p);
+}
+
+static uint32_t create_context(int i915, unsigned int class, unsigned int inst, int prio)
+{
+ uint32_t ctx;
+
+ ctx = gem_context_create_for_engine(i915, class, inst);
+ set_unbannable(i915, ctx);
+ gem_context_set_priority(i915, ctx, prio);
+
+ return ctx;
+}
+
+static uint64_t __test_timeout(int i915, int engine, unsigned int timeout)
+{
+ unsigned int class, inst;
+ struct timespec ts = {};
+ igt_spin_t *spin[2];
+ uint64_t elapsed;
+ uint32_t ctx[2];
+
+ igt_assert(igt_sysfs_scanf(engine, "class", "%u", &class) == 1);
+ igt_assert(igt_sysfs_scanf(engine, "instance", "%u", &inst) == 1);
+
+ set_preempt_timeout(engine, timeout);
+
+ ctx[0] = create_context(i915, class, inst, -1023);
+ spin[0] = igt_spin_new(i915, ctx[0],
+ .flags = (IGT_SPIN_NO_PREEMPTION |
+ IGT_SPIN_POLL_RUN |
+ IGT_SPIN_FENCE_OUT));
+ igt_spin_busywait_until_started(spin[0]);
+
+ ctx[1] = create_context(i915, class, inst, 1023);
+ igt_nsec_elapsed(&ts);
+ spin[1] = igt_spin_new(i915, ctx[1], .flags = IGT_SPIN_POLL_RUN);
+ igt_spin_busywait_until_started(spin[1]);
+ elapsed = igt_nsec_elapsed(&ts);
+
+ igt_spin_free(i915, spin[1]);
+
+ igt_assert_eq(sync_fence_wait(spin[0]->out_fence, RESET_TIMEOUT), 0);
+ igt_assert_eq(sync_fence_status(spin[0]->out_fence), -EIO);
+
+ igt_spin_free(i915, spin[0]);
+
+ gem_context_destroy(i915, ctx[1]);
+ gem_context_destroy(i915, ctx[0]);
+ gem_quiescent_gpu(i915);
+
+ return elapsed;
+}
+
+static void test_timeout(int i915, int engine)
+{
+ int delays[] = { 1, 50, 100, 500 };
+ unsigned int saved;
+
+ /*
+ * Send down some non-preemptable workloads and then request a
+ * switch to a higher priority context. The HW will not be able to
+ * respond, so the kernel will be forced to reset the hog. This
+ * timeout should match our specification, and so we can measure
+ * the delay from requesting the preemption to its completion.
+ */
+
+ igt_assert(igt_sysfs_scanf(engine, ATTR, "%u", &saved) == 1);
+ igt_debug("Initial %s:%u\n", ATTR, saved);
+
+ gem_quiescent_gpu(i915);
+ igt_require(enable_hangcheck(i915, false));
+
+ for (int i = 0; i < ARRAY_SIZE(delays); i++) {
+ uint64_t elapsed;
+
+ elapsed = __test_timeout(i915, engine, delays[i]);
+ igt_info("%s:%d, elapsed=%.3fms\n",
+ ATTR, delays[i], elapsed * 1e-6);
+
+ /*
+ * We need to give a couple of jiffies slack for the scheduler timeouts
+ * and then a little more slack fr the overhead in submitting and
+ * measuring. 50ms should cover all of our sins and be useful
+ * tolerance.
+ */
+ igt_assert_f(elapsed / 1000 / 1000 < delays[i] + 50,
+ "Forced preemption timeout exceeded request!\n");
+ }
+
+ igt_assert(enable_hangcheck(i915, true));
+ gem_quiescent_gpu(i915);
+ set_preempt_timeout(engine, saved);
+}
+
+static void test_off(int i915, int engine)
+{
+ unsigned int class, inst;
+ igt_spin_t *spin[2];
+ unsigned int saved;
+ uint32_t ctx[2];
+
+ /*
+ * We support setting the timeout to 0 to disable the reset on
+ * preemption failure. Having established that we can do forced
+ * preemption on demand, we use the same setup (non-preeemptable hog
+ * followed by a high priority context) and verify that the hog is
+ * never reset. Never is a long time, so we settle for 150s.
+ */
+
+ igt_assert(igt_sysfs_scanf(engine, ATTR, "%u", &saved) == 1);
+ igt_debug("Initial %s:%u\n", ATTR, saved);
+
+ gem_quiescent_gpu(i915);
+ igt_require(enable_hangcheck(i915, false));
+
+ igt_assert(igt_sysfs_scanf(engine, "class", "%u", &class) == 1);
+ igt_assert(igt_sysfs_scanf(engine, "instance", "%u", &inst) == 1);
+
+ set_preempt_timeout(engine, 0);
+
+ ctx[0] = create_context(i915, class, inst, -1023);
+ spin[0] = igt_spin_new(i915, ctx[0],
+ .flags = (IGT_SPIN_NO_PREEMPTION |
+ IGT_SPIN_POLL_RUN |
+ IGT_SPIN_FENCE_OUT));
+ igt_spin_busywait_until_started(spin[0]);
+
+ ctx[1] = create_context(i915, class, inst, 1023);
+ spin[1] = igt_spin_new(i915, ctx[1], .flags = IGT_SPIN_POLL_RUN);
+
+ for (int i = 0; i < 150; i++) {
+ igt_assert_eq(sync_fence_status(spin[0]->out_fence), 0);
+ sleep(1);
+ }
+
+ set_preempt_timeout(engine, 1);
+
+ igt_spin_busywait_until_started(spin[1]);
+ igt_spin_free(i915, spin[1]);
+
+ igt_assert_eq(sync_fence_wait(spin[0]->out_fence, RESET_TIMEOUT), 0);
+ igt_assert_eq(sync_fence_status(spin[0]->out_fence), -EIO);
+
+ igt_spin_free(i915, spin[0]);
+
+ gem_context_destroy(i915, ctx[1]);
+ gem_context_destroy(i915, ctx[0]);
+
+ igt_assert(enable_hangcheck(i915, true));
+ gem_quiescent_gpu(i915);
+
+ set_preempt_timeout(engine, saved);
+}
+
+igt_main
+{
+ static const struct {
+ const char *name;
+ void (*fn)(int, int);
+ } tests[] = {
+ { "idempotent", test_idempotent },
+ { "invalid", test_invalid },
+ { "timeout", test_timeout },
+ { "off", test_off },
+ { }
+ };
+ int i915 = -1, engines = -1;
+
+ igt_fixture {
+ int sys;
+
+ i915 = drm_open_driver(DRIVER_INTEL);
+ igt_require_gem(i915);
+ igt_allow_hang(i915, 0, 0);
+
+ sys = igt_sysfs_open(i915);
+ igt_require(sys != -1);
+
+ engines = openat(sys, "engine", O_RDONLY);
+ igt_require(engines != -1);
+
+ close(sys);
+ }
+
+ for (typeof(*tests) *t = tests; t->name; t++)
+ igt_subtest_with_dynamic(t->name)
+ dyn_sysfs_engines(i915, engines, ATTR, t->fn);
+
+ igt_fixture {
+ close(engines);
+ close(i915);
+ }
+}
diff --git a/tests/intel-ci/blacklist.txt b/tests/intel-ci/blacklist.txt
index 8085719f5..1b5442278 100644
--- a/tests/intel-ci/blacklist.txt
+++ b/tests/intel-ci/blacklist.txt
@@ -60,6 +60,7 @@ igt at gem_sync@(?!.*basic).*
igt at gem_tiled_swapping@(?!non-threaded).*
igt at gem_userptr_blits@(major|minor|forked|mlocked|swapping).*
igt at gem_wait@.*hang.*
+igt at sysfs_preemption_timeout@off.*
###############################################
# GEM: Not worth fixing
###############################################
diff --git a/tests/meson.build b/tests/meson.build
index 9280eb3d8..bafd00513 100644
--- a/tests/meson.build
+++ b/tests/meson.build
@@ -227,6 +227,7 @@ i915_progs = [
'i915_query',
'i915_selftest',
'i915_suspend',
+ 'sysfs_preempt_timeout',
]
test_deps = [ igt_deps ]
--
2.25.1
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