1 // SPDX-License-Identifier: MIT
3 * Copyright © 2019 Intel Corporation
6 #include <linux/kobject.h>
7 #include <linux/sysfs.h>
10 #include "intel_engine.h"
11 #include "intel_engine_heartbeat.h"
12 #include "sysfs_engines.h"
16 struct intel_engine_cs *engine;
19 static struct intel_engine_cs *kobj_to_engine(struct kobject *kobj)
21 return container_of(kobj, struct kobj_engine, base)->engine;
25 name_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
27 return sprintf(buf, "%s\n", kobj_to_engine(kobj)->name);
30 static struct kobj_attribute name_attr =
31 __ATTR(name, 0444, name_show, NULL);
34 class_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
36 return sprintf(buf, "%d\n", kobj_to_engine(kobj)->uabi_class);
39 static struct kobj_attribute class_attr =
40 __ATTR(class, 0444, class_show, NULL);
43 inst_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
45 return sprintf(buf, "%d\n", kobj_to_engine(kobj)->uabi_instance);
48 static struct kobj_attribute inst_attr =
49 __ATTR(instance, 0444, inst_show, NULL);
52 mmio_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
54 return sprintf(buf, "0x%x\n", kobj_to_engine(kobj)->mmio_base);
57 static struct kobj_attribute mmio_attr =
58 __ATTR(mmio_base, 0444, mmio_show, NULL);
60 static const char * const vcs_caps[] = {
61 [ilog2(I915_VIDEO_CLASS_CAPABILITY_HEVC)] = "hevc",
62 [ilog2(I915_VIDEO_AND_ENHANCE_CLASS_CAPABILITY_SFC)] = "sfc",
65 static const char * const vecs_caps[] = {
66 [ilog2(I915_VIDEO_AND_ENHANCE_CLASS_CAPABILITY_SFC)] = "sfc",
69 static ssize_t repr_trim(char *buf, ssize_t len)
71 /* Trim off the trailing space and replace with a newline */
81 __caps_show(struct intel_engine_cs *engine,
82 unsigned long caps, char *buf, bool show_unknown)
84 const char * const *repr;
88 switch (engine->class) {
89 case VIDEO_DECODE_CLASS:
91 count = ARRAY_SIZE(vcs_caps);
94 case VIDEO_ENHANCEMENT_CLASS:
96 count = ARRAY_SIZE(vecs_caps);
104 GEM_BUG_ON(count > BITS_PER_LONG);
107 for_each_set_bit(n, &caps, show_unknown ? BITS_PER_LONG : count) {
108 if (n >= count || !repr[n]) {
109 if (GEM_WARN_ON(show_unknown))
110 len += snprintf(buf + len, PAGE_SIZE - len,
113 len += snprintf(buf + len, PAGE_SIZE - len,
116 if (GEM_WARN_ON(len >= PAGE_SIZE))
119 return repr_trim(buf, len);
123 caps_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
125 struct intel_engine_cs *engine = kobj_to_engine(kobj);
127 return __caps_show(engine, engine->uabi_capabilities, buf, true);
130 static struct kobj_attribute caps_attr =
131 __ATTR(capabilities, 0444, caps_show, NULL);
134 all_caps_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
136 return __caps_show(kobj_to_engine(kobj), -1, buf, false);
139 static struct kobj_attribute all_caps_attr =
140 __ATTR(known_capabilities, 0444, all_caps_show, NULL);
143 max_spin_store(struct kobject *kobj, struct kobj_attribute *attr,
144 const char *buf, size_t count)
146 struct intel_engine_cs *engine = kobj_to_engine(kobj);
147 unsigned long long duration;
151 * When waiting for a request, if is it currently being executed
152 * on the GPU, we busywait for a short while before sleeping. The
153 * premise is that most requests are short, and if it is already
154 * executing then there is a good chance that it will complete
155 * before we can setup the interrupt handler and go to sleep.
156 * We try to offset the cost of going to sleep, by first spinning
157 * on the request -- if it completed in less time than it would take
158 * to go sleep, process the interrupt and return back to the client,
159 * then we have saved the client some latency, albeit at the cost
160 * of spinning on an expensive CPU core.
162 * While we try to avoid waiting at all for a request that is unlikely
163 * to complete, deciding how long it is worth spinning is for is an
164 * arbitrary decision: trading off power vs latency.
167 err = kstrtoull(buf, 0, &duration);
171 if (duration > jiffies_to_nsecs(2))
174 WRITE_ONCE(engine->props.max_busywait_duration_ns, duration);
180 max_spin_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
182 struct intel_engine_cs *engine = kobj_to_engine(kobj);
184 return sprintf(buf, "%lu\n", engine->props.max_busywait_duration_ns);
187 static struct kobj_attribute max_spin_attr =
188 __ATTR(max_busywait_duration_ns, 0644, max_spin_show, max_spin_store);
191 max_spin_default(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
193 struct intel_engine_cs *engine = kobj_to_engine(kobj);
195 return sprintf(buf, "%lu\n", engine->defaults.max_busywait_duration_ns);
198 static struct kobj_attribute max_spin_def =
199 __ATTR(max_busywait_duration_ns, 0444, max_spin_default, NULL);
202 timeslice_store(struct kobject *kobj, struct kobj_attribute *attr,
203 const char *buf, size_t count)
205 struct intel_engine_cs *engine = kobj_to_engine(kobj);
206 unsigned long long duration;
210 * Execlists uses a scheduling quantum (a timeslice) to alternate
211 * execution between ready-to-run contexts of equal priority. This
212 * ensures that all users (though only if they of equal importance)
213 * have the opportunity to run and prevents livelocks where contexts
214 * may have implicit ordering due to userspace semaphores.
217 err = kstrtoull(buf, 0, &duration);
221 if (duration > jiffies_to_msecs(MAX_SCHEDULE_TIMEOUT))
224 WRITE_ONCE(engine->props.timeslice_duration_ms, duration);
226 if (execlists_active(&engine->execlists))
227 set_timer_ms(&engine->execlists.timer, duration);
233 timeslice_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
235 struct intel_engine_cs *engine = kobj_to_engine(kobj);
237 return sprintf(buf, "%lu\n", engine->props.timeslice_duration_ms);
240 static struct kobj_attribute timeslice_duration_attr =
241 __ATTR(timeslice_duration_ms, 0644, timeslice_show, timeslice_store);
244 timeslice_default(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
246 struct intel_engine_cs *engine = kobj_to_engine(kobj);
248 return sprintf(buf, "%lu\n", engine->defaults.timeslice_duration_ms);
251 static struct kobj_attribute timeslice_duration_def =
252 __ATTR(timeslice_duration_ms, 0444, timeslice_default, NULL);
255 stop_store(struct kobject *kobj, struct kobj_attribute *attr,
256 const char *buf, size_t count)
258 struct intel_engine_cs *engine = kobj_to_engine(kobj);
259 unsigned long long duration;
263 * When we allow ourselves to sleep before a GPU reset after disabling
264 * submission, even for a few milliseconds, gives an innocent context
265 * the opportunity to clear the GPU before the reset occurs. However,
266 * how long to sleep depends on the typical non-preemptible duration
267 * (a similar problem to determining the ideal preempt-reset timeout
268 * or even the heartbeat interval).
271 err = kstrtoull(buf, 0, &duration);
275 if (duration > jiffies_to_msecs(MAX_SCHEDULE_TIMEOUT))
278 WRITE_ONCE(engine->props.stop_timeout_ms, duration);
283 stop_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
285 struct intel_engine_cs *engine = kobj_to_engine(kobj);
287 return sprintf(buf, "%lu\n", engine->props.stop_timeout_ms);
290 static struct kobj_attribute stop_timeout_attr =
291 __ATTR(stop_timeout_ms, 0644, stop_show, stop_store);
294 stop_default(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
296 struct intel_engine_cs *engine = kobj_to_engine(kobj);
298 return sprintf(buf, "%lu\n", engine->defaults.stop_timeout_ms);
301 static struct kobj_attribute stop_timeout_def =
302 __ATTR(stop_timeout_ms, 0444, stop_default, NULL);
305 preempt_timeout_store(struct kobject *kobj, struct kobj_attribute *attr,
306 const char *buf, size_t count)
308 struct intel_engine_cs *engine = kobj_to_engine(kobj);
309 unsigned long long timeout;
313 * After initialising a preemption request, we give the current
314 * resident a small amount of time to vacate the GPU. The preemption
315 * request is for a higher priority context and should be immediate to
316 * maintain high quality of service (and avoid priority inversion).
317 * However, the preemption granularity of the GPU can be quite coarse
318 * and so we need a compromise.
321 err = kstrtoull(buf, 0, &timeout);
325 if (timeout > jiffies_to_msecs(MAX_SCHEDULE_TIMEOUT))
328 WRITE_ONCE(engine->props.preempt_timeout_ms, timeout);
330 if (READ_ONCE(engine->execlists.pending[0]))
331 set_timer_ms(&engine->execlists.preempt, timeout);
337 preempt_timeout_show(struct kobject *kobj, struct kobj_attribute *attr,
340 struct intel_engine_cs *engine = kobj_to_engine(kobj);
342 return sprintf(buf, "%lu\n", engine->props.preempt_timeout_ms);
345 static struct kobj_attribute preempt_timeout_attr =
346 __ATTR(preempt_timeout_ms, 0644, preempt_timeout_show, preempt_timeout_store);
349 preempt_timeout_default(struct kobject *kobj, struct kobj_attribute *attr,
352 struct intel_engine_cs *engine = kobj_to_engine(kobj);
354 return sprintf(buf, "%lu\n", engine->defaults.preempt_timeout_ms);
357 static struct kobj_attribute preempt_timeout_def =
358 __ATTR(preempt_timeout_ms, 0444, preempt_timeout_default, NULL);
361 heartbeat_store(struct kobject *kobj, struct kobj_attribute *attr,
362 const char *buf, size_t count)
364 struct intel_engine_cs *engine = kobj_to_engine(kobj);
365 unsigned long long delay;
369 * We monitor the health of the system via periodic heartbeat pulses.
370 * The pulses also provide the opportunity to perform garbage
371 * collection. However, we interpret an incomplete pulse (a missed
372 * heartbeat) as an indication that the system is no longer responsive,
373 * i.e. hung, and perform an engine or full GPU reset. Given that the
374 * preemption granularity can be very coarse on a system, the optimal
375 * value for any workload is unknowable!
378 err = kstrtoull(buf, 0, &delay);
382 if (delay >= jiffies_to_msecs(MAX_SCHEDULE_TIMEOUT))
385 err = intel_engine_set_heartbeat(engine, delay);
393 heartbeat_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
395 struct intel_engine_cs *engine = kobj_to_engine(kobj);
397 return sprintf(buf, "%lu\n", engine->props.heartbeat_interval_ms);
400 static struct kobj_attribute heartbeat_interval_attr =
401 __ATTR(heartbeat_interval_ms, 0644, heartbeat_show, heartbeat_store);
404 heartbeat_default(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
406 struct intel_engine_cs *engine = kobj_to_engine(kobj);
408 return sprintf(buf, "%lu\n", engine->defaults.heartbeat_interval_ms);
411 static struct kobj_attribute heartbeat_interval_def =
412 __ATTR(heartbeat_interval_ms, 0444, heartbeat_default, NULL);
414 static void kobj_engine_release(struct kobject *kobj)
419 static struct kobj_type kobj_engine_type = {
420 .release = kobj_engine_release,
421 .sysfs_ops = &kobj_sysfs_ops
424 static struct kobject *
425 kobj_engine(struct kobject *dir, struct intel_engine_cs *engine)
427 struct kobj_engine *ke;
429 ke = kzalloc(sizeof(*ke), GFP_KERNEL);
433 kobject_init(&ke->base, &kobj_engine_type);
436 if (kobject_add(&ke->base, dir, "%s", engine->name)) {
437 kobject_put(&ke->base);
441 /* xfer ownership to sysfs tree */
445 static void add_defaults(struct kobj_engine *parent)
447 static const struct attribute *files[] = {
449 &stop_timeout_def.attr,
450 #if CONFIG_DRM_I915_HEARTBEAT_INTERVAL
451 &heartbeat_interval_def.attr,
455 struct kobj_engine *ke;
457 ke = kzalloc(sizeof(*ke), GFP_KERNEL);
461 kobject_init(&ke->base, &kobj_engine_type);
462 ke->engine = parent->engine;
464 if (kobject_add(&ke->base, &parent->base, "%s", ".defaults")) {
465 kobject_put(&ke->base);
469 if (sysfs_create_files(&ke->base, files))
472 if (intel_engine_has_timeslices(ke->engine) &&
473 sysfs_create_file(&ke->base, ×lice_duration_def.attr))
476 if (intel_engine_has_preempt_reset(ke->engine) &&
477 sysfs_create_file(&ke->base, &preempt_timeout_def.attr))
481 void intel_engines_add_sysfs(struct drm_i915_private *i915)
483 static const struct attribute *files[] = {
491 &stop_timeout_attr.attr,
492 #if CONFIG_DRM_I915_HEARTBEAT_INTERVAL
493 &heartbeat_interval_attr.attr,
498 struct device *kdev = i915->drm.primary->kdev;
499 struct intel_engine_cs *engine;
502 dir = kobject_create_and_add("engine", &kdev->kobj);
506 for_each_uabi_engine(engine, i915) {
507 struct kobject *kobj;
509 kobj = kobj_engine(dir, engine);
513 if (sysfs_create_files(kobj, files))
516 if (intel_engine_has_timeslices(engine) &&
517 sysfs_create_file(kobj, ×lice_duration_attr.attr))
520 if (intel_engine_has_preempt_reset(engine) &&
521 sysfs_create_file(kobj, &preempt_timeout_attr.attr))
524 add_defaults(container_of(kobj, struct kobj_engine, base));
530 dev_err(kdev, "Failed to add sysfs engine '%s'\n",