1 // Copyright (c) 2011 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #include "remoting/host/capture_scheduler.h" 6 7 #include <algorithm> 8 9 #include "base/logging.h" 10 #include "base/sys_info.h" 11 #include "base/time/time.h" 12 13 namespace { 14 15 // Number of samples to average the most recent capture and encode time 16 // over. 17 const int kStatisticsWindow = 3; 18 19 // The hard limit is 30fps or 33ms per recording cycle. 20 const int64 kDefaultMinimumIntervalMs = 33; 21 22 // Controls how much CPU time we can use for encode and capture. 23 // Range of this value is between 0 to 1. 0 means using 0% of of all CPUs 24 // available while 1 means using 100% of all CPUs available. 25 const double kRecordingCpuConsumption = 0.5; 26 27 } // namespace 28 29 namespace remoting { 30 31 // We assume that the number of available cores is constant. 32 CaptureScheduler::CaptureScheduler() 33 : minimum_interval_( 34 base::TimeDelta::FromMilliseconds(kDefaultMinimumIntervalMs)), 35 num_of_processors_(base::SysInfo::NumberOfProcessors()), 36 capture_time_(kStatisticsWindow), 37 encode_time_(kStatisticsWindow) { 38 DCHECK(num_of_processors_); 39 } 40 41 CaptureScheduler::~CaptureScheduler() { 42 } 43 44 base::TimeDelta CaptureScheduler::NextCaptureDelay() { 45 // Delay by an amount chosen such that if capture and encode times 46 // continue to follow the averages, then we'll consume the target 47 // fraction of CPU across all cores. 48 base::TimeDelta delay = base::TimeDelta::FromMilliseconds( 49 (capture_time_.Average() + encode_time_.Average()) / 50 (kRecordingCpuConsumption * num_of_processors_)); 51 52 if (delay < minimum_interval_) 53 return minimum_interval_; 54 return delay; 55 } 56 57 void CaptureScheduler::RecordCaptureTime(base::TimeDelta capture_time) { 58 capture_time_.Record(capture_time.InMilliseconds()); 59 } 60 61 void CaptureScheduler::RecordEncodeTime(base::TimeDelta encode_time) { 62 encode_time_.Record(encode_time.InMilliseconds()); 63 } 64 65 void CaptureScheduler::SetNumOfProcessorsForTest(int num_of_processors) { 66 num_of_processors_ = num_of_processors; 67 } 68 69 } // namespace remoting 70
