Jamie Gennis | faf77cc | 2013-07-30 15:10:32 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2013 The Android Open Source Project |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | |
| 17 | #define ATRACE_TAG ATRACE_TAG_GRAPHICS |
| 18 | |
| 19 | // This is needed for stdint.h to define INT64_MAX in C++ |
| 20 | #define __STDC_LIMIT_MACROS |
| 21 | |
| 22 | #include <math.h> |
| 23 | |
| 24 | #include <cutils/log.h> |
| 25 | |
| 26 | #include <ui/Fence.h> |
| 27 | |
| 28 | #include <utils/String8.h> |
| 29 | #include <utils/Thread.h> |
| 30 | #include <utils/Trace.h> |
| 31 | #include <utils/Vector.h> |
| 32 | |
| 33 | #include "DispSync.h" |
| 34 | #include "EventLog/EventLog.h" |
| 35 | |
| 36 | namespace android { |
| 37 | |
| 38 | // Setting this to true enables verbose tracing that can be used to debug |
| 39 | // vsync event model or phase issues. |
| 40 | static const bool traceDetailedInfo = false; |
| 41 | |
| 42 | // This is the threshold used to determine when hardware vsync events are |
| 43 | // needed to re-synchronize the software vsync model with the hardware. The |
| 44 | // error metric used is the mean of the squared difference between each |
| 45 | // present time and the nearest software-predicted vsync. |
| 46 | static const nsecs_t errorThreshold = 160000000000; |
| 47 | |
| 48 | // This works around the lack of support for the sync framework on some |
| 49 | // devices. |
| 50 | #ifdef RUNNING_WITHOUT_SYNC_FRAMEWORK |
| 51 | static const bool runningWithoutSyncFramework = true; |
| 52 | #else |
| 53 | static const bool runningWithoutSyncFramework = false; |
| 54 | #endif |
| 55 | |
| 56 | // This is the offset from the present fence timestamps to the corresponding |
| 57 | // vsync event. |
| 58 | static const int64_t presentTimeOffset = PRESENT_TIME_OFFSET_FROM_VSYNC_NS; |
| 59 | |
| 60 | class DispSyncThread: public Thread { |
| 61 | public: |
| 62 | |
| 63 | DispSyncThread(): |
| 64 | mStop(false), |
| 65 | mPeriod(0), |
| 66 | mPhase(0), |
| 67 | mWakeupLatency(0) { |
| 68 | } |
| 69 | |
| 70 | virtual ~DispSyncThread() {} |
| 71 | |
| 72 | void updateModel(nsecs_t period, nsecs_t phase) { |
| 73 | Mutex::Autolock lock(mMutex); |
| 74 | mPeriod = period; |
| 75 | mPhase = phase; |
| 76 | mCond.signal(); |
| 77 | } |
| 78 | |
| 79 | void stop() { |
| 80 | Mutex::Autolock lock(mMutex); |
| 81 | mStop = true; |
| 82 | mCond.signal(); |
| 83 | } |
| 84 | |
| 85 | virtual bool threadLoop() { |
| 86 | status_t err; |
| 87 | nsecs_t now = systemTime(SYSTEM_TIME_MONOTONIC); |
| 88 | nsecs_t nextEventTime = 0; |
| 89 | |
| 90 | while (true) { |
| 91 | Vector<CallbackInvocation> callbackInvocations; |
| 92 | |
| 93 | nsecs_t targetTime = 0; |
| 94 | |
| 95 | { // Scope for lock |
| 96 | Mutex::Autolock lock(mMutex); |
| 97 | |
| 98 | if (mStop) { |
| 99 | return false; |
| 100 | } |
| 101 | |
| 102 | if (mPeriod == 0) { |
| 103 | err = mCond.wait(mMutex); |
| 104 | if (err != NO_ERROR) { |
| 105 | ALOGE("error waiting for new events: %s (%d)", |
| 106 | strerror(-err), err); |
| 107 | return false; |
| 108 | } |
| 109 | continue; |
| 110 | } |
| 111 | |
| 112 | nextEventTime = computeNextEventTimeLocked(now); |
| 113 | targetTime = nextEventTime - mWakeupLatency; |
| 114 | |
| 115 | bool isWakeup = false; |
| 116 | |
| 117 | if (now < targetTime) { |
| 118 | err = mCond.waitRelative(mMutex, targetTime - now); |
| 119 | |
| 120 | if (err == TIMED_OUT) { |
| 121 | isWakeup = true; |
| 122 | } else if (err != NO_ERROR) { |
| 123 | ALOGE("error waiting for next event: %s (%d)", |
| 124 | strerror(-err), err); |
| 125 | return false; |
| 126 | } |
| 127 | } |
| 128 | |
| 129 | now = systemTime(SYSTEM_TIME_MONOTONIC); |
| 130 | |
| 131 | if (isWakeup) { |
| 132 | mWakeupLatency = ((mWakeupLatency * 63) + |
| 133 | (now - targetTime)) / 64; |
| 134 | if (mWakeupLatency > 500000) { |
| 135 | // Don't correct by more than 500 us |
| 136 | mWakeupLatency = 500000; |
| 137 | } |
| 138 | if (traceDetailedInfo) { |
| 139 | ATRACE_INT64("DispSync:WakeupLat", now - nextEventTime); |
| 140 | ATRACE_INT64("DispSync:AvgWakeupLat", mWakeupLatency); |
| 141 | } |
| 142 | } |
| 143 | |
| 144 | callbackInvocations = gatherCallbackInvocationsLocked(now); |
| 145 | } |
| 146 | |
| 147 | if (callbackInvocations.size() > 0) { |
| 148 | fireCallbackInvocations(callbackInvocations); |
| 149 | } |
| 150 | } |
| 151 | |
| 152 | return false; |
| 153 | } |
| 154 | |
| 155 | status_t addEventListener(nsecs_t phase, const sp<DispSync::Callback>& callback) { |
| 156 | Mutex::Autolock lock(mMutex); |
| 157 | |
| 158 | for (size_t i = 0; i < mEventListeners.size(); i++) { |
| 159 | if (mEventListeners[i].mCallback == callback) { |
| 160 | return BAD_VALUE; |
| 161 | } |
| 162 | } |
| 163 | |
| 164 | EventListener listener; |
| 165 | listener.mPhase = phase; |
| 166 | listener.mCallback = callback; |
| 167 | listener.mLastEventTime = systemTime(SYSTEM_TIME_MONOTONIC); |
| 168 | mEventListeners.push(listener); |
| 169 | |
| 170 | mCond.signal(); |
| 171 | |
| 172 | return NO_ERROR; |
| 173 | } |
| 174 | |
| 175 | status_t removeEventListener(const sp<DispSync::Callback>& callback) { |
| 176 | Mutex::Autolock lock(mMutex); |
| 177 | |
| 178 | for (size_t i = 0; i < mEventListeners.size(); i++) { |
| 179 | if (mEventListeners[i].mCallback == callback) { |
| 180 | mEventListeners.removeAt(i); |
| 181 | mCond.signal(); |
| 182 | return NO_ERROR; |
| 183 | } |
| 184 | } |
| 185 | |
| 186 | return BAD_VALUE; |
| 187 | } |
| 188 | |
| 189 | // This method is only here to handle the runningWithoutSyncFramework |
| 190 | // case. |
| 191 | bool hasAnyEventListeners() { |
| 192 | Mutex::Autolock lock(mMutex); |
| 193 | return !mEventListeners.empty(); |
| 194 | } |
| 195 | |
| 196 | private: |
| 197 | |
| 198 | struct EventListener { |
| 199 | nsecs_t mPhase; |
| 200 | nsecs_t mLastEventTime; |
| 201 | sp<DispSync::Callback> mCallback; |
| 202 | }; |
| 203 | |
| 204 | struct CallbackInvocation { |
| 205 | sp<DispSync::Callback> mCallback; |
| 206 | nsecs_t mEventTime; |
| 207 | }; |
| 208 | |
| 209 | nsecs_t computeNextEventTimeLocked(nsecs_t now) { |
| 210 | nsecs_t nextEventTime = INT64_MAX; |
| 211 | for (size_t i = 0; i < mEventListeners.size(); i++) { |
| 212 | nsecs_t t = computeListenerNextEventTimeLocked(mEventListeners[i], |
| 213 | now); |
| 214 | |
| 215 | if (t < nextEventTime) { |
| 216 | nextEventTime = t; |
| 217 | } |
| 218 | } |
| 219 | |
| 220 | return nextEventTime; |
| 221 | } |
| 222 | |
| 223 | Vector<CallbackInvocation> gatherCallbackInvocationsLocked(nsecs_t now) { |
| 224 | Vector<CallbackInvocation> callbackInvocations; |
| 225 | nsecs_t ref = now - mPeriod; |
| 226 | |
| 227 | for (size_t i = 0; i < mEventListeners.size(); i++) { |
| 228 | nsecs_t t = computeListenerNextEventTimeLocked(mEventListeners[i], |
| 229 | ref); |
| 230 | |
| 231 | if (t - mWakeupLatency < now) { |
| 232 | CallbackInvocation ci; |
| 233 | ci.mCallback = mEventListeners[i].mCallback; |
| 234 | ci.mEventTime = t; |
| 235 | callbackInvocations.push(ci); |
| 236 | mEventListeners.editItemAt(i).mLastEventTime = t; |
| 237 | } |
| 238 | } |
| 239 | |
| 240 | return callbackInvocations; |
| 241 | } |
| 242 | |
| 243 | nsecs_t computeListenerNextEventTimeLocked(const EventListener& listener, |
| 244 | nsecs_t ref) { |
| 245 | |
| 246 | nsecs_t lastEventTime = listener.mLastEventTime; |
| 247 | if (ref < lastEventTime) { |
| 248 | ref = lastEventTime; |
| 249 | } |
| 250 | |
| 251 | nsecs_t phase = mPhase + listener.mPhase; |
| 252 | nsecs_t t = (((ref - phase) / mPeriod) + 1) * mPeriod + phase; |
| 253 | |
| 254 | if (t - listener.mLastEventTime < mPeriod / 2) { |
| 255 | t += mPeriod; |
| 256 | } |
| 257 | |
| 258 | return t; |
| 259 | } |
| 260 | |
| 261 | void fireCallbackInvocations(const Vector<CallbackInvocation>& callbacks) { |
| 262 | for (size_t i = 0; i < callbacks.size(); i++) { |
| 263 | callbacks[i].mCallback->onDispSyncEvent(callbacks[i].mEventTime); |
| 264 | } |
| 265 | } |
| 266 | |
| 267 | bool mStop; |
| 268 | |
| 269 | nsecs_t mPeriod; |
| 270 | nsecs_t mPhase; |
| 271 | nsecs_t mWakeupLatency; |
| 272 | |
| 273 | Vector<EventListener> mEventListeners; |
| 274 | |
| 275 | Mutex mMutex; |
| 276 | Condition mCond; |
| 277 | }; |
| 278 | |
| 279 | class ZeroPhaseTracer : public DispSync::Callback { |
| 280 | public: |
| 281 | ZeroPhaseTracer() : mParity(false) {} |
| 282 | |
| 283 | virtual void onDispSyncEvent(nsecs_t when) { |
| 284 | mParity = !mParity; |
| 285 | ATRACE_INT("ZERO_PHASE_VSYNC", mParity ? 1 : 0); |
| 286 | } |
| 287 | |
| 288 | private: |
| 289 | bool mParity; |
| 290 | }; |
| 291 | |
| 292 | DispSync::DispSync() { |
| 293 | mThread = new DispSyncThread(); |
| 294 | mThread->run("DispSync", PRIORITY_URGENT_DISPLAY + PRIORITY_MORE_FAVORABLE); |
| 295 | |
| 296 | reset(); |
| 297 | beginResync(); |
| 298 | |
| 299 | if (traceDetailedInfo) { |
| 300 | // If runningWithoutSyncFramework is true then the ZeroPhaseTracer |
| 301 | // would prevent HW vsync event from ever being turned off. |
| 302 | // Furthermore the zero-phase tracing is not needed because any time |
| 303 | // there is an event registered we will turn on the HW vsync events. |
| 304 | if (!runningWithoutSyncFramework) { |
| 305 | addEventListener(0, new ZeroPhaseTracer()); |
| 306 | } |
| 307 | } |
| 308 | } |
| 309 | |
| 310 | DispSync::~DispSync() {} |
| 311 | |
| 312 | void DispSync::reset() { |
| 313 | Mutex::Autolock lock(mMutex); |
| 314 | |
| 315 | mNumResyncSamples = 0; |
| 316 | mFirstResyncSample = 0; |
| 317 | mNumResyncSamplesSincePresent = 0; |
| 318 | resetErrorLocked(); |
| 319 | } |
| 320 | |
| 321 | bool DispSync::addPresentFence(const sp<Fence>& fence) { |
| 322 | Mutex::Autolock lock(mMutex); |
| 323 | |
| 324 | mPresentFences[mPresentSampleOffset] = fence; |
| 325 | mPresentTimes[mPresentSampleOffset] = 0; |
| 326 | mPresentSampleOffset = (mPresentSampleOffset + 1) % NUM_PRESENT_SAMPLES; |
| 327 | mNumResyncSamplesSincePresent = 0; |
| 328 | |
| 329 | for (size_t i = 0; i < NUM_PRESENT_SAMPLES; i++) { |
| 330 | const sp<Fence>& f(mPresentFences[i]); |
| 331 | if (f != NULL) { |
| 332 | nsecs_t t = f->getSignalTime(); |
| 333 | if (t < INT64_MAX) { |
| 334 | mPresentFences[i].clear(); |
| 335 | mPresentTimes[i] = t + presentTimeOffset; |
| 336 | } |
| 337 | } |
| 338 | } |
| 339 | |
| 340 | updateErrorLocked(); |
| 341 | |
| 342 | return mPeriod == 0 || mError > errorThreshold; |
| 343 | } |
| 344 | |
| 345 | void DispSync::beginResync() { |
| 346 | Mutex::Autolock lock(mMutex); |
| 347 | |
| 348 | mNumResyncSamples = 0; |
| 349 | } |
| 350 | |
| 351 | bool DispSync::addResyncSample(nsecs_t timestamp) { |
| 352 | Mutex::Autolock lock(mMutex); |
| 353 | |
| 354 | size_t idx = (mFirstResyncSample + mNumResyncSamples) % MAX_RESYNC_SAMPLES; |
| 355 | mResyncSamples[idx] = timestamp; |
| 356 | |
| 357 | if (mNumResyncSamples < MAX_RESYNC_SAMPLES) { |
| 358 | mNumResyncSamples++; |
| 359 | } else { |
| 360 | mFirstResyncSample = (mFirstResyncSample + 1) % MAX_RESYNC_SAMPLES; |
| 361 | } |
| 362 | |
| 363 | updateModelLocked(); |
| 364 | |
| 365 | if (mNumResyncSamplesSincePresent++ > MAX_RESYNC_SAMPLES_WITHOUT_PRESENT) { |
| 366 | resetErrorLocked(); |
| 367 | } |
| 368 | |
| 369 | if (runningWithoutSyncFramework) { |
| 370 | // If we don't have the sync framework we will never have |
| 371 | // addPresentFence called. This means we have no way to know whether |
| 372 | // or not we're synchronized with the HW vsyncs, so we just request |
| 373 | // that the HW vsync events be turned on whenever we need to generate |
| 374 | // SW vsync events. |
| 375 | return mThread->hasAnyEventListeners(); |
| 376 | } |
| 377 | |
| 378 | return mPeriod == 0 || mError > errorThreshold; |
| 379 | } |
| 380 | |
| 381 | void DispSync::endResync() { |
| 382 | } |
| 383 | |
| 384 | status_t DispSync::addEventListener(nsecs_t phase, |
| 385 | const sp<Callback>& callback) { |
| 386 | |
| 387 | Mutex::Autolock lock(mMutex); |
| 388 | return mThread->addEventListener(phase, callback); |
| 389 | } |
| 390 | |
| 391 | status_t DispSync::removeEventListener(const sp<Callback>& callback) { |
| 392 | Mutex::Autolock lock(mMutex); |
| 393 | return mThread->removeEventListener(callback); |
| 394 | } |
| 395 | |
| 396 | void DispSync::setPeriod(nsecs_t period) { |
| 397 | Mutex::Autolock lock(mMutex); |
| 398 | mPeriod = period; |
| 399 | mPhase = 0; |
Jesse Hall | 72f69d9 | 2013-10-10 14:48:22 -0700 | [diff] [blame^] | 400 | mThread->updateModel(mPeriod, mPhase); |
Jamie Gennis | faf77cc | 2013-07-30 15:10:32 -0700 | [diff] [blame] | 401 | } |
| 402 | |
| 403 | void DispSync::updateModelLocked() { |
| 404 | if (mNumResyncSamples >= MIN_RESYNC_SAMPLES_FOR_UPDATE) { |
| 405 | nsecs_t durationSum = 0; |
| 406 | for (size_t i = 1; i < mNumResyncSamples; i++) { |
| 407 | size_t idx = (mFirstResyncSample + i) % MAX_RESYNC_SAMPLES; |
| 408 | size_t prev = (idx + MAX_RESYNC_SAMPLES - 1) % MAX_RESYNC_SAMPLES; |
| 409 | durationSum += mResyncSamples[idx] - mResyncSamples[prev]; |
| 410 | } |
| 411 | |
| 412 | mPeriod = durationSum / (mNumResyncSamples - 1); |
| 413 | |
| 414 | double sampleAvgX = 0; |
| 415 | double sampleAvgY = 0; |
| 416 | double scale = 2.0 * M_PI / double(mPeriod); |
| 417 | for (size_t i = 0; i < mNumResyncSamples; i++) { |
| 418 | size_t idx = (mFirstResyncSample + i) % MAX_RESYNC_SAMPLES; |
| 419 | nsecs_t sample = mResyncSamples[idx]; |
| 420 | double samplePhase = double(sample % mPeriod) * scale; |
| 421 | sampleAvgX += cos(samplePhase); |
| 422 | sampleAvgY += sin(samplePhase); |
| 423 | } |
| 424 | |
| 425 | sampleAvgX /= double(mNumResyncSamples); |
| 426 | sampleAvgY /= double(mNumResyncSamples); |
| 427 | |
| 428 | mPhase = nsecs_t(atan2(sampleAvgY, sampleAvgX) / scale); |
| 429 | |
| 430 | if (mPhase < 0) { |
| 431 | mPhase += mPeriod; |
| 432 | } |
| 433 | |
| 434 | if (traceDetailedInfo) { |
| 435 | ATRACE_INT64("DispSync:Period", mPeriod); |
| 436 | ATRACE_INT64("DispSync:Phase", mPhase); |
| 437 | } |
| 438 | |
| 439 | mThread->updateModel(mPeriod, mPhase); |
| 440 | } |
| 441 | } |
| 442 | |
| 443 | void DispSync::updateErrorLocked() { |
| 444 | if (mPeriod == 0) { |
| 445 | return; |
| 446 | } |
| 447 | |
| 448 | int numErrSamples = 0; |
| 449 | nsecs_t sqErrSum = 0; |
| 450 | |
| 451 | for (size_t i = 0; i < NUM_PRESENT_SAMPLES; i++) { |
| 452 | nsecs_t sample = mPresentTimes[i]; |
| 453 | if (sample > mPhase) { |
| 454 | nsecs_t sampleErr = (sample - mPhase) % mPeriod; |
| 455 | if (sampleErr > mPeriod / 2) { |
| 456 | sampleErr -= mPeriod; |
| 457 | } |
| 458 | sqErrSum += sampleErr * sampleErr; |
| 459 | numErrSamples++; |
| 460 | } |
| 461 | } |
| 462 | |
| 463 | if (numErrSamples > 0) { |
| 464 | mError = sqErrSum / numErrSamples; |
| 465 | } else { |
| 466 | mError = 0; |
| 467 | } |
| 468 | |
| 469 | if (traceDetailedInfo) { |
| 470 | ATRACE_INT64("DispSync:Error", mError); |
| 471 | } |
| 472 | } |
| 473 | |
| 474 | void DispSync::resetErrorLocked() { |
| 475 | mPresentSampleOffset = 0; |
| 476 | mError = 0; |
| 477 | for (size_t i = 0; i < NUM_PRESENT_SAMPLES; i++) { |
| 478 | mPresentFences[i].clear(); |
| 479 | mPresentTimes[i] = 0; |
| 480 | } |
| 481 | } |
| 482 | |
| 483 | } // namespace android |