[igt-dev] [PATCH i-g-t 4/5] i915: Exercise sysfs heartbeat controls
Chris Wilson
chris at chris-wilson.co.uk
Mon Jan 27 12:18:17 UTC 2020
We [will] expose various per-engine scheduling controls. One of which,
'heartbeat_duration_ms', defines how often we send a heartbeat down the
engine to check upon the health of the engine. If a heartbeat does not
complete within the interval (or two), the engine is declared hung.
Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
tests/Makefile.sources | 3 +
tests/i915/sysfs_heartbeat_interval.c | 466 ++++++++++++++++++++++++++
tests/meson.build | 1 +
3 files changed, 470 insertions(+)
create mode 100644 tests/i915/sysfs_heartbeat_interval.c
diff --git a/tests/Makefile.sources b/tests/Makefile.sources
index fc9e04e97..fd6f67a73 100644
--- a/tests/Makefile.sources
+++ b/tests/Makefile.sources
@@ -102,6 +102,9 @@ TESTS_progs = \
vgem_slow \
$(NULL)
+TESTS_progs += sysfs_heartbeat_interval
+sysfs_heartbeat_interval_SOURCES = i915/sysfs_heartbeat_interval
+
TESTS_progs += sysfs_preempt_timeout
sysfs_preempt_timeout_SOURCES = i915/sysfs_preempt_timeout
diff --git a/tests/i915/sysfs_heartbeat_interval.c b/tests/i915/sysfs_heartbeat_interval.c
new file mode 100644
index 000000000..9ce7b7b85
--- /dev/null
+++ b/tests/i915/sysfs_heartbeat_interval.c
@@ -0,0 +1,466 @@
+/*
+ * 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 <signal.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <sys/wait.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"
+
+static bool __enable_hangcheck(int dir, bool state)
+{
+ return igt_sysfs_set(dir, "enable_hangcheck", state ? "1" : "0");
+}
+
+static void enable_hangcheck(int i915, bool state)
+{
+ int dir;
+
+ dir = igt_sysfs_open_parameters(i915);
+ if (dir < 0) /* no parameters, must be default! */
+ return;
+
+ __enable_hangcheck(dir, state);
+ close(dir);
+}
+
+static void set_heartbeat(int engine, unsigned int value)
+{
+ unsigned int delay = ~value;
+
+ igt_sysfs_printf(engine, "heartbeat_interval_ms", "%u", value);
+ igt_sysfs_scanf(engine, "heartbeat_interval_ms", "%u", &delay);
+ igt_assert_eq(delay, value);
+}
+
+static void test_idempotent(int i915, int engine)
+{
+ unsigned int delays[] = { 1, 1000, 5000, 50000, 123456789 };
+ unsigned int saved;
+
+ /* Quick test that the property reports the values we set */
+
+ igt_assert(igt_sysfs_scanf(engine, "heartbeat_interval_ms", "%u", &saved) == 1);
+ igt_debug("Initial heartbeat_interval_ms:%u\n", saved);
+
+ for (int i = 0; i < ARRAY_SIZE(delays); i++)
+ set_heartbeat(engine, delays[i]);
+
+ set_heartbeat(engine, saved);
+}
+
+static void test_invalid(int i915, int engine)
+{
+ unsigned int saved, delay;
+
+ /* Quick test that we reject any unrepresentable intervals */
+
+ igt_assert(igt_sysfs_scanf(engine, "heartbeat_interval_ms", "%u", &saved) == 1);
+ igt_debug("Initial heartbeat_interval_ms:%u\n", saved);
+
+ igt_sysfs_printf(engine, "heartbeat_interval_ms", PRIu64, -1);
+ igt_sysfs_scanf(engine, "heartbeat_interval_ms", "%u", &delay);
+ igt_assert_eq(delay, saved);
+
+ igt_sysfs_printf(engine, "heartbeat_interval_ms", PRIu64, 10ull << 32);
+ igt_sysfs_scanf(engine, "heartbeat_interval_ms", "%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,
+ };
+
+ igt_assert_eq(__gem_context_set_param(i915, &p), 0);
+}
+
+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_heartbeat(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, 1), 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_precise(int i915, int engine)
+{
+ int delays[] = { 1, 50, 100, 500 };
+ unsigned int saved;
+
+ /*
+ * The heartbeat interval defines how long the kernel waits between
+ * checking on the status of the engines. It first sends down a
+ * heartbeat pulse, waits the interval and sees if the system managed
+ * to complete the pulse. If not, it gives a priority bump to the pulse
+ * and waits again. This is repeated until the priority cannot be bumped
+ * any more, and the system is declared hung.
+ *
+ * If we combine the preemptive pulse with forced preemption, we instead
+ * get a much faster hang detection. Thus in combination we can measure
+ * the system response time to reseting a hog as a measure of the
+ * heartbeat interval, and so confirm it matches our specification.
+ */
+
+ igt_require(igt_sysfs_printf(engine, "preempt_timeout_ms", "%u", 1) == 1);
+
+ igt_assert(igt_sysfs_scanf(engine, "heartbeat_interval_ms", "%u", &saved) == 1);
+ igt_debug("Initial heartbeat_interval_ms:%u\n", saved);
+ gem_quiescent_gpu(i915);
+
+ for (int i = 0; i < ARRAY_SIZE(delays); i++) {
+ uint64_t elapsed;
+
+ elapsed = __test_timeout(i915, engine, delays[i]);
+ igt_info("heartbeat_interval_ms:%d, elapsed=%.3fms[%d]\n",
+ delays[i], elapsed * 1e-6,
+ (int)(elapsed / 1000 / 1000)
+ );
+
+ /*
+ * It takes a couple of missed heartbeats before we start
+ * terminating hogs, and a little bit of jiffie slack for
+ * scheduling at each step. 150ms should cover all of our
+ * sins and be useful tolerance.
+ */
+ igt_assert_f(elapsed / 1000 / 1000 < 3 * delays[i] + 150,
+ "Heartbeat interval (and CPR) exceeded request!\n");
+ }
+
+ gem_quiescent_gpu(i915);
+ set_heartbeat(engine, saved);
+}
+
+static void test_nopreempt(int i915, int engine)
+{
+ int delays[] = { 1, 50, 100, 500 };
+ unsigned int saved;
+
+ /*
+ * The same principle as test_precise(), except that forced preemption
+ * is disabled (or simply not supported by the platform). This time,
+ * it waits until the system misses a few heartbeat before doing a
+ * per-engine/full-gpu reset. As such it is less precise, but we
+ * can still estimate an upper bound for our specified heartbeat
+ * interval and verify the system conforms.
+ */
+
+ /* Test heartbeats with forced preemption disabled */
+ igt_sysfs_printf(engine, "preempt_timeout_ms", "%u", 0);
+
+ igt_assert(igt_sysfs_scanf(engine, "heartbeat_interval_ms", "%u", &saved) == 1);
+ igt_debug("Initial heartbeat_interval_ms:%u\n", saved);
+ gem_quiescent_gpu(i915);
+
+ for (int i = 0; i < ARRAY_SIZE(delays); i++) {
+ uint64_t elapsed;
+
+ elapsed = __test_timeout(i915, engine, delays[i]);
+ igt_info("heartbeat_interval_ms:%d, elapsed=%.3fms[%d]\n",
+ delays[i], elapsed * 1e-6,
+ (int)(elapsed / 1000 / 1000)
+ );
+
+ /*
+ * It takes a several missed heartbeats before we start
+ * terminating hogs, and a little bit of jiffie slack for
+ * scheduling at each step. 250ms should cover all of our
+ * sins and be useful tolerance.
+ */
+ igt_assert_f(elapsed / 1000 / 1000 < 5 * delays[i] + 150,
+ "Heartbeat interval (and CPR) exceeded request!\n");
+ }
+
+ gem_quiescent_gpu(i915);
+ set_heartbeat(engine, saved);
+}
+
+static void client(int i915, int engine, int *ctl, int duration, int expect)
+{
+ unsigned int class, inst;
+ unsigned long count = 0;
+ uint32_t ctx;
+
+ igt_assert(igt_sysfs_scanf(engine, "class", "%u", &class) == 1);
+ igt_assert(igt_sysfs_scanf(engine, "instance", "%u", &inst) == 1);
+
+ ctx = create_context(i915, class, inst, 0);
+
+ while (!READ_ONCE(*ctl)) {
+ igt_spin_t *spin;
+
+ spin = igt_spin_new(i915, ctx,
+ .flags = (IGT_SPIN_NO_PREEMPTION |
+ IGT_SPIN_POLL_RUN |
+ IGT_SPIN_FENCE_OUT));
+ igt_spin_busywait_until_started(spin);
+
+ igt_spin_set_timeout(spin, (uint64_t)duration * 1000 * 1000);
+ sync_fence_wait(spin->out_fence, -1);
+
+ igt_assert_eq(sync_fence_status(spin->out_fence), expect);
+ count++;
+ }
+
+ gem_context_destroy(i915, ctx);
+ igt_info("%s client completed %lu spins\n",
+ expect < 0 ? "Bad" : "Good", count);
+}
+
+static void sigign(int sig)
+{
+}
+
+static void wait_until(int duration)
+{
+ signal(SIGCHLD, sigign);
+ sleep(duration);
+ signal(SIGCHLD, SIG_IGN);
+}
+
+static void __test_mixed(int i915, int engine,
+ int heartbeat,
+ int good,
+ int bad,
+ int duration)
+{
+ unsigned int saved;
+ int *shared;
+
+ /*
+ * Given two clients of which one is a hog, be sure we cleanly
+ * terminate the hog leaving the good client to run.
+ */
+
+ igt_assert(igt_sysfs_scanf(engine, "heartbeat_interval_ms", "%u", &saved) == 1);
+ igt_debug("Initial heartbeat_interval_ms:%u\n", saved);
+ gem_quiescent_gpu(i915);
+
+ shared = mmap(NULL, 4096, PROT_WRITE, MAP_SHARED | MAP_ANON, -1, 0);
+ igt_assert(shared != MAP_FAILED);
+
+ set_heartbeat(engine, heartbeat);
+
+ igt_fork(child, 1) /* good client */
+ client(i915, engine, shared, good, 1);
+ igt_fork(child, 1) /* bad client */
+ client(i915, engine, shared, bad, -EIO);
+
+ wait_until(duration);
+
+ *shared = true;
+ igt_waitchildren();
+ munmap(shared, 4096);
+
+ gem_quiescent_gpu(i915);
+ set_heartbeat(engine, saved);
+}
+
+static void test_mixed(int i915, int engine)
+{
+ /*
+ * Hogs rarely run alone. Our hang detection must carefully wean
+ * out the hogs from the innocent clients. Thus we run a mixed workload
+ * with non-preemptable hogs that exceed the heartbeat, and quicker
+ * innocents. We inspect the fence status of each to verify that
+ * only the hogs are reset.
+ */
+ igt_sysfs_printf(engine, "preempt_timeout_ms", "%u", 1);
+ __test_mixed(i915, engine, 10, 10, 100, 5);
+}
+
+static void test_long(int i915, int engine)
+{
+ /*
+ * Some clients relish being hogs, and demand that the system
+ * never do hangchecking. Never is hard to test, so instead we
+ * run over a day and verify that only the super hogs are reset.
+ */
+ igt_sysfs_printf(engine, "preempt_timeout_ms", "%u", 0);
+ __test_mixed(i915, engine,
+ 60 * 1000, /* 60s */
+ 60 * 1000, /* 60s */
+ 300 * 1000, /* 5min */
+ 24 * 3600 /* 24hours */);
+}
+
+static void test_off(int i915, int engine)
+{
+ unsigned int class, inst;
+ unsigned int saved;
+ igt_spin_t *spin;
+ uint32_t ctx;
+
+ /*
+ * Some other clients request that there is never any interruption
+ * or jitter in their workload and so demand that the kernel never
+ * sends a heartbeat to steal precious cycles from their workload.
+ * Turn off the heartbeat and check that the workload is uninterrupted
+ * for 150s.
+ */
+
+ igt_assert(igt_sysfs_scanf(engine, "heartbeat_interval_ms", "%u", &saved) == 1);
+ igt_debug("Initial heartbeat_interval_ms:%u\n", saved);
+ gem_quiescent_gpu(i915);
+
+ igt_assert(igt_sysfs_scanf(engine, "class", "%u", &class) == 1);
+ igt_assert(igt_sysfs_scanf(engine, "instance", "%u", &inst) == 1);
+
+ set_heartbeat(engine, 0);
+
+ ctx = create_context(i915, class, inst, 0);
+
+ spin = igt_spin_new(i915, ctx,
+ .flags = (IGT_SPIN_POLL_RUN |
+ IGT_SPIN_NO_PREEMPTION |
+ IGT_SPIN_FENCE_OUT));
+ igt_spin_busywait_until_started(spin);
+
+ for (int i = 0; i < 150; i++) {
+ igt_assert_eq(sync_fence_status(spin->out_fence), 0);
+ sleep(1);
+ }
+
+ set_heartbeat(engine, 1);
+
+ igt_assert_eq(sync_fence_wait(spin->out_fence, 250), 0);
+ igt_assert_eq(sync_fence_status(spin->out_fence), -EIO);
+
+ igt_spin_free(i915, spin);
+
+ gem_quiescent_gpu(i915);
+ set_heartbeat(engine, saved);
+}
+
+igt_main
+{
+ 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);
+
+ enable_hangcheck(i915, true);
+ }
+
+ igt_subtest_with_dynamic("idempotent")
+ dyn_sysfs_engines(i915, engines, "heartbeat_interval_ms",
+ test_idempotent);
+
+ igt_subtest_with_dynamic("invalid")
+ dyn_sysfs_engines(i915, engines, "heartbeat_interval_ms",
+ test_invalid);
+
+ igt_subtest_with_dynamic("precise")
+ dyn_sysfs_engines(i915, engines, "heartbeat_interval_ms",
+ test_precise);
+
+ igt_subtest_with_dynamic("nopreempt")
+ dyn_sysfs_engines(i915, engines, "heartbeat_interval_ms",
+ test_nopreempt);
+
+ igt_subtest_with_dynamic("mixed")
+ dyn_sysfs_engines(i915, engines, "heartbeat_interval_ms",
+ test_mixed);
+
+ igt_subtest_with_dynamic("off")
+ dyn_sysfs_engines(i915, engines, "heartbeat_interval_ms",
+ test_off);
+
+ igt_subtest_with_dynamic("long")
+ dyn_sysfs_engines(i915, engines, "heartbeat_interval_ms",
+ test_long);
+
+ igt_fixture {
+ close(engines);
+ close(i915);
+ }
+}
diff --git a/tests/meson.build b/tests/meson.build
index 1893f2c34..8795dfe1b 100644
--- a/tests/meson.build
+++ b/tests/meson.build
@@ -238,6 +238,7 @@ i915_progs = [
'i915_query',
'i915_selftest',
'i915_suspend',
+ 'sysfs_heartbeat_interval',
'sysfs_preempt_timeout',
]
--
2.25.0
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