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 20fps or 50ms per recording cycle. 20 const int64 kMinimumRecordingDelay = 50; 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. CaptureScheduler()32CaptureScheduler::CaptureScheduler() 33 : num_of_processors_(base::SysInfo::NumberOfProcessors()), 34 capture_time_(kStatisticsWindow), 35 encode_time_(kStatisticsWindow) { 36 DCHECK(num_of_processors_); 37 } 38 ~CaptureScheduler()39CaptureScheduler::~CaptureScheduler() { 40 } 41 NextCaptureDelay()42base::TimeDelta CaptureScheduler::NextCaptureDelay() { 43 // Delay by an amount chosen such that if capture and encode times 44 // continue to follow the averages, then we'll consume the target 45 // fraction of CPU across all cores. 46 double delay = 47 (capture_time_.Average() + encode_time_.Average()) / 48 (kRecordingCpuConsumption * num_of_processors_); 49 50 if (delay < kMinimumRecordingDelay) 51 return base::TimeDelta::FromMilliseconds(kMinimumRecordingDelay); 52 return base::TimeDelta::FromMilliseconds(delay); 53 } 54 RecordCaptureTime(base::TimeDelta capture_time)55void CaptureScheduler::RecordCaptureTime(base::TimeDelta capture_time) { 56 capture_time_.Record(capture_time.InMilliseconds()); 57 } 58 RecordEncodeTime(base::TimeDelta encode_time)59void CaptureScheduler::RecordEncodeTime(base::TimeDelta encode_time) { 60 encode_time_.Record(encode_time.InMilliseconds()); 61 } 62 SetNumOfProcessorsForTest(int num_of_processors)63void CaptureScheduler::SetNumOfProcessorsForTest(int num_of_processors) { 64 num_of_processors_ = num_of_processors; 65 } 66 67 } // namespace remoting 68