MonoPipe.cpp revision 6d8aabe8a3be1ac0789d00b82c3ca8b81381f5ab
1010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten/* 2010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten * Copyright (C) 2012 The Android Open Source Project 3010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten * 4010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten * Licensed under the Apache License, Version 2.0 (the "License"); 5010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten * you may not use this file except in compliance with the License. 6010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten * You may obtain a copy of the License at 7010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten * 8010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten * http://www.apache.org/licenses/LICENSE-2.0 9010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten * 10010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten * Unless required by applicable law or agreed to in writing, software 11010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten * distributed under the License is distributed on an "AS IS" BASIS, 12010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten * See the License for the specific language governing permissions and 14010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten * limitations under the License. 15010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten */ 16010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten 17010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten#define LOG_TAG "MonoPipe" 18010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten//#define LOG_NDEBUG 0 19010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten 20010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten#include <cutils/atomic.h> 21010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten#include <cutils/compiler.h> 22010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten#include <utils/Log.h> 23010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten#include "MonoPipe.h" 24010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten#include "roundup.h" 25010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten 26010662326b9c43c703725f933e95e0897f8a6bddGlenn Kastennamespace android { 27010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten 28010662326b9c43c703725f933e95e0897f8a6bddGlenn KastenMonoPipe::MonoPipe(size_t maxFrames, NBAIO_Format format, bool writeCanBlock) : 29010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten NBAIO_Sink(format), 30010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten mMaxFrames(roundup(maxFrames)), 31010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten mBuffer(malloc(mMaxFrames * Format_frameSize(format))), 32010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten mFront(0), 33010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten mRear(0), 34010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten mWriteCanBlock(writeCanBlock) 35010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten{ 36010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten} 37010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten 38010662326b9c43c703725f933e95e0897f8a6bddGlenn KastenMonoPipe::~MonoPipe() 39010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten{ 40010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten free(mBuffer); 41010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten} 42010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten 43010662326b9c43c703725f933e95e0897f8a6bddGlenn Kastenssize_t MonoPipe::availableToWrite() const 44010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten{ 45010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten if (CC_UNLIKELY(!mNegotiated)) { 46010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten return NEGOTIATE; 47010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten } 48010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten ssize_t ret = mMaxFrames - (mRear - android_atomic_acquire_load(&mFront)); 49010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten ALOG_ASSERT((0 <= ret) && (ret <= mMaxFrames)); 50010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten return ret; 51010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten} 52010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten 53010662326b9c43c703725f933e95e0897f8a6bddGlenn Kastenssize_t MonoPipe::write(const void *buffer, size_t count) 54010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten{ 55010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten if (CC_UNLIKELY(!mNegotiated)) { 56010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten return NEGOTIATE; 57010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten } 58010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten size_t totalFramesWritten = 0; 596d8aabe8a3be1ac0789d00b82c3ca8b81381f5abGlenn Kasten while (count > 0) { 606d8aabe8a3be1ac0789d00b82c3ca8b81381f5abGlenn Kasten size_t avail = availableToWrite(); 616d8aabe8a3be1ac0789d00b82c3ca8b81381f5abGlenn Kasten size_t written = avail; 62010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten if (CC_LIKELY(written > count)) { 63010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten written = count; 64010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten } 65010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten size_t rear = mRear & (mMaxFrames - 1); 66010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten size_t part1 = mMaxFrames - rear; 67010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten if (part1 > written) { 68010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten part1 = written; 69010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten } 70010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten if (CC_LIKELY(part1 > 0)) { 71010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten memcpy((char *) mBuffer + (rear << mBitShift), buffer, part1 << mBitShift); 72010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten if (CC_UNLIKELY(rear + part1 == mMaxFrames)) { 73010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten size_t part2 = written - part1; 74010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten if (CC_LIKELY(part2 > 0)) { 75010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten memcpy(mBuffer, (char *) buffer + (part1 << mBitShift), part2 << mBitShift); 76010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten } 77010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten } 78010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten android_atomic_release_store(written + mRear, &mRear); 79010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten totalFramesWritten += written; 80010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten } 816d8aabe8a3be1ac0789d00b82c3ca8b81381f5abGlenn Kasten if (!mWriteCanBlock) { 82010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten break; 83010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten } 846d8aabe8a3be1ac0789d00b82c3ca8b81381f5abGlenn Kasten count -= written; 85010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten buffer = (char *) buffer + (written << mBitShift); 866d8aabe8a3be1ac0789d00b82c3ca8b81381f5abGlenn Kasten // Simulate blocking I/O by sleeping at different rates, depending on a throttle. 876d8aabe8a3be1ac0789d00b82c3ca8b81381f5abGlenn Kasten // The throttle tries to keep the pipe about 5/8 full on average, with a slight jitter. 886d8aabe8a3be1ac0789d00b82c3ca8b81381f5abGlenn Kasten uint64_t ns; 896d8aabe8a3be1ac0789d00b82c3ca8b81381f5abGlenn Kasten enum { 906d8aabe8a3be1ac0789d00b82c3ca8b81381f5abGlenn Kasten THROTTLE_VERY_FAST, // pipe is (nearly) empty, fill quickly 916d8aabe8a3be1ac0789d00b82c3ca8b81381f5abGlenn Kasten THROTTLE_FAST, // pipe is normal, fill at slightly faster rate 926d8aabe8a3be1ac0789d00b82c3ca8b81381f5abGlenn Kasten THROTTLE_NOMINAL, // pipe is normal, fill at nominal rate 936d8aabe8a3be1ac0789d00b82c3ca8b81381f5abGlenn Kasten THROTTLE_SLOW, // pipe is normal, fill at slightly slower rate 946d8aabe8a3be1ac0789d00b82c3ca8b81381f5abGlenn Kasten THROTTLE_VERY_SLOW, // pipe is (nearly) full, fill slowly 956d8aabe8a3be1ac0789d00b82c3ca8b81381f5abGlenn Kasten } throttle; 966d8aabe8a3be1ac0789d00b82c3ca8b81381f5abGlenn Kasten avail -= written; 976d8aabe8a3be1ac0789d00b82c3ca8b81381f5abGlenn Kasten // FIXME cache these values to avoid re-computation 986d8aabe8a3be1ac0789d00b82c3ca8b81381f5abGlenn Kasten if (avail >= (mMaxFrames * 3) / 4) { 996d8aabe8a3be1ac0789d00b82c3ca8b81381f5abGlenn Kasten throttle = THROTTLE_VERY_FAST; 1006d8aabe8a3be1ac0789d00b82c3ca8b81381f5abGlenn Kasten } else if (avail >= mMaxFrames / 2) { 1016d8aabe8a3be1ac0789d00b82c3ca8b81381f5abGlenn Kasten throttle = THROTTLE_FAST; 1026d8aabe8a3be1ac0789d00b82c3ca8b81381f5abGlenn Kasten } else if (avail >= (mMaxFrames * 3) / 8) { 1036d8aabe8a3be1ac0789d00b82c3ca8b81381f5abGlenn Kasten throttle = THROTTLE_NOMINAL; 1046d8aabe8a3be1ac0789d00b82c3ca8b81381f5abGlenn Kasten } else if (avail >= mMaxFrames / 4) { 1056d8aabe8a3be1ac0789d00b82c3ca8b81381f5abGlenn Kasten throttle = THROTTLE_SLOW; 1066d8aabe8a3be1ac0789d00b82c3ca8b81381f5abGlenn Kasten } else { 1076d8aabe8a3be1ac0789d00b82c3ca8b81381f5abGlenn Kasten throttle = THROTTLE_VERY_SLOW; 1086d8aabe8a3be1ac0789d00b82c3ca8b81381f5abGlenn Kasten } 1096d8aabe8a3be1ac0789d00b82c3ca8b81381f5abGlenn Kasten if (written > 0) { 1106d8aabe8a3be1ac0789d00b82c3ca8b81381f5abGlenn Kasten // FIXME cache these values also 1116d8aabe8a3be1ac0789d00b82c3ca8b81381f5abGlenn Kasten switch (throttle) { 1126d8aabe8a3be1ac0789d00b82c3ca8b81381f5abGlenn Kasten case THROTTLE_VERY_FAST: 1136d8aabe8a3be1ac0789d00b82c3ca8b81381f5abGlenn Kasten default: 1146d8aabe8a3be1ac0789d00b82c3ca8b81381f5abGlenn Kasten ns = written * ( 500000000 / Format_sampleRate(mFormat)); 1156d8aabe8a3be1ac0789d00b82c3ca8b81381f5abGlenn Kasten break; 1166d8aabe8a3be1ac0789d00b82c3ca8b81381f5abGlenn Kasten case THROTTLE_FAST: 1176d8aabe8a3be1ac0789d00b82c3ca8b81381f5abGlenn Kasten ns = written * ( 750000000 / Format_sampleRate(mFormat)); 1186d8aabe8a3be1ac0789d00b82c3ca8b81381f5abGlenn Kasten break; 1196d8aabe8a3be1ac0789d00b82c3ca8b81381f5abGlenn Kasten case THROTTLE_NOMINAL: 1206d8aabe8a3be1ac0789d00b82c3ca8b81381f5abGlenn Kasten ns = written * (1000000000 / Format_sampleRate(mFormat)); 1216d8aabe8a3be1ac0789d00b82c3ca8b81381f5abGlenn Kasten break; 1226d8aabe8a3be1ac0789d00b82c3ca8b81381f5abGlenn Kasten case THROTTLE_SLOW: 1236d8aabe8a3be1ac0789d00b82c3ca8b81381f5abGlenn Kasten ns = written * (1100000000 / Format_sampleRate(mFormat)); 1246d8aabe8a3be1ac0789d00b82c3ca8b81381f5abGlenn Kasten break; 1256d8aabe8a3be1ac0789d00b82c3ca8b81381f5abGlenn Kasten case THROTTLE_VERY_SLOW: 1266d8aabe8a3be1ac0789d00b82c3ca8b81381f5abGlenn Kasten ns = written * (1250000000 / Format_sampleRate(mFormat)); 1276d8aabe8a3be1ac0789d00b82c3ca8b81381f5abGlenn Kasten break; 1286d8aabe8a3be1ac0789d00b82c3ca8b81381f5abGlenn Kasten } 1296d8aabe8a3be1ac0789d00b82c3ca8b81381f5abGlenn Kasten } else { 1306d8aabe8a3be1ac0789d00b82c3ca8b81381f5abGlenn Kasten ns = mMaxFrames * (250000000 / Format_sampleRate(mFormat)); 1316d8aabe8a3be1ac0789d00b82c3ca8b81381f5abGlenn Kasten } 1326d8aabe8a3be1ac0789d00b82c3ca8b81381f5abGlenn Kasten if (ns > 999999999) { 1336d8aabe8a3be1ac0789d00b82c3ca8b81381f5abGlenn Kasten ns = 999999999; 1346d8aabe8a3be1ac0789d00b82c3ca8b81381f5abGlenn Kasten } 1356d8aabe8a3be1ac0789d00b82c3ca8b81381f5abGlenn Kasten struct timespec sleep; 1366d8aabe8a3be1ac0789d00b82c3ca8b81381f5abGlenn Kasten sleep.tv_sec = 0; 1376d8aabe8a3be1ac0789d00b82c3ca8b81381f5abGlenn Kasten sleep.tv_nsec = ns; 1386d8aabe8a3be1ac0789d00b82c3ca8b81381f5abGlenn Kasten nanosleep(&sleep, NULL); 139010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten } 140010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten mFramesWritten += totalFramesWritten; 141010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten return totalFramesWritten; 142010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten} 143010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten 144010662326b9c43c703725f933e95e0897f8a6bddGlenn Kasten} // namespace android 145