| // Copyright (c) 2011 The Chromium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #include "remoting/host/capture_scheduler.h" |
| |
| #include <algorithm> |
| |
| #include "base/logging.h" |
| #include "base/sys_info.h" |
| #include "base/time/time.h" |
| |
| namespace { |
| |
| // Number of samples to average the most recent capture and encode time |
| // over. |
| const int kStatisticsWindow = 3; |
| |
| // The hard limit is 30fps or 33ms per recording cycle. |
| const int64 kDefaultMinimumIntervalMs = 33; |
| |
| // Controls how much CPU time we can use for encode and capture. |
| // Range of this value is between 0 to 1. 0 means using 0% of of all CPUs |
| // available while 1 means using 100% of all CPUs available. |
| const double kRecordingCpuConsumption = 0.5; |
| |
| } // namespace |
| |
| namespace remoting { |
| |
| // We assume that the number of available cores is constant. |
| CaptureScheduler::CaptureScheduler() |
| : minimum_interval_( |
| base::TimeDelta::FromMilliseconds(kDefaultMinimumIntervalMs)), |
| num_of_processors_(base::SysInfo::NumberOfProcessors()), |
| capture_time_(kStatisticsWindow), |
| encode_time_(kStatisticsWindow) { |
| DCHECK(num_of_processors_); |
| } |
| |
| CaptureScheduler::~CaptureScheduler() { |
| } |
| |
| base::TimeDelta CaptureScheduler::NextCaptureDelay() { |
| // Delay by an amount chosen such that if capture and encode times |
| // continue to follow the averages, then we'll consume the target |
| // fraction of CPU across all cores. |
| base::TimeDelta delay = base::TimeDelta::FromMilliseconds( |
| (capture_time_.Average() + encode_time_.Average()) / |
| (kRecordingCpuConsumption * num_of_processors_)); |
| |
| if (delay < minimum_interval_) |
| return minimum_interval_; |
| return delay; |
| } |
| |
| void CaptureScheduler::RecordCaptureTime(base::TimeDelta capture_time) { |
| capture_time_.Record(capture_time.InMilliseconds()); |
| } |
| |
| void CaptureScheduler::RecordEncodeTime(base::TimeDelta encode_time) { |
| encode_time_.Record(encode_time.InMilliseconds()); |
| } |
| |
| void CaptureScheduler::SetNumOfProcessorsForTest(int num_of_processors) { |
| num_of_processors_ = num_of_processors; |
| } |
| |
| } // namespace remoting |