Experimental patch for adapting adaptation to CPU count on Mac.

webrtc/video/overuse_frame_detector.cc

 /*
  *  Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
 #include "webrtc/video/overuse_frame_detector.h"
 
 #include <assert.h>
 #include <math.h>
 
 #include <algorithm>
 #include <list>
 #include <map>
 
 #include "webrtc/base/checks.h"
 #include "webrtc/base/exp_filter.h"
 #include "webrtc/base/logging.h"
 #include "webrtc/frame_callback.h"
 #include "webrtc/system_wrappers/include/clock.h"
 #include "webrtc/video_frame.h"
 
+#if defined(WEBRTC_MAC)
+#include <mach/mach.h>
+#endif
+
 namespace webrtc {
 
 namespace {
 const int64_t kProcessIntervalMs = 5000;
 
 // Delay between consecutive rampups. (Used for quick recovery.)
 const int kQuickRampUpDelayMs = 10 * 1000;
 // Delay between rampup attempts. Initially uses standard, scales up to max.
 const int kStandardRampUpDelayMs = 40 * 1000;
 const int kMaxRampUpDelayMs = 240 * 1000;
 // Expontential back-off factor, to prevent annoying up-down behaviour.
 const double kRampUpBackoffFactor = 2.0;
 
 // Max number of overuses detected before always applying the rampup delay.
 const int kMaxOverusesBeforeApplyRampupDelay = 4;
 
 // The maximum exponent to use in VCMExpFilter.
 const float kSampleDiffMs = 33.0f;
 const float kMaxExp = 7.0f;
 
 }  // namespace
 
+CpuOveruseOptions::CpuOveruseOptions()
+    : high_encode_usage_threshold_percent(85),
+      frame_timeout_interval_ms(1500),
+      min_frame_samples(120),
+      min_process_count(3),
+      high_threshold_consecutive_count(2) {
+#if defined(WEBRTC_MAC)
+  // This is proof-of-concept code for letting the physical core count affect
+  // the interval into which we attempt to scale. For now, the code is Mac OS
+  // specific, since that's the platform were we saw most problems.
+  // TODO(torbjorng): Enhance SystemInfo to return this metric.
+
+  mach_port_t mach_host = mach_host_self();
+  host_basic_info hbi = {};
+  mach_msg_type_number_t info_count = HOST_BASIC_INFO_COUNT;
+  kern_return_t kr =
+      host_info(mach_host, HOST_BASIC_INFO, reinterpret_cast<host_info_t>(&hbi),
+                &info_count);
+  mach_port_deallocate(mach_task_self(), mach_host);
+
+  int n_physical_cores;
+  if (kr != KERN_SUCCESS) {
+    // If we couldn't get # of physical CPUs, don't panic. Assume we have 1.
+    n_physical_cores = 1;
+    LOG(LS_ERROR) << "Failed to determine number of physical cores, assuming 1";
+  } else {
+    n_physical_cores = hbi.physical_cpu;
+    LOG(LS_INFO) << "Number of physical cores:" << n_physical_cores;
+  }
+
+  // Change init list default for few core systems. The assumption here is that
+  // encoding, which we measure here, takes about 1/4 of the processing of a
+  // two-way call. This is roughly true for x86 using both vp8 and vp9 without
+  // hardware encoding. Since we don't affect the incoming stream here, we only
+  // control about 1/2 of the total processing needs, but this is not taken into
+  // account.
+  if (n_physical_cores == 1)
+    high_encode_usage_threshold_percent = 20;  // Roughly 1/4 of 100%.
+  else if (n_physical_cores == 2)
+    high_encode_usage_threshold_percent = 40;  // Roughly 1/4 of 200%.
+
+#endif  // WEBRTC_MAC
+  // Note that we make the interval 2x+epsilon wide, since libyuv scaling steps
+  // are close to that (when squared). This wide interval makes sure that
+  // scaling up or down does not jump all the way across the interval.
+  low_encode_usage_threshold_percent =
+      (high_encode_usage_threshold_percent - 1) / 2;
+}
+
 // Class for calculating the processing usage on the send-side (the average
 // processing time of a frame divided by the average time difference between
 // captured frames).
 class OveruseFrameDetector::SendProcessingUsage {
  public:
   explicit SendProcessingUsage(const CpuOveruseOptions& options)
       : kWeightFactorFrameDiff(0.998f),
         kWeightFactorProcessing(0.995f),
         kInitialSampleDiffMs(40.0f),
         kMaxSampleDiffMs(45.0f),
@@ skipping 263 matching lines @@
 bool OveruseFrameDetector::IsUnderusing(const CpuOveruseMetrics& metrics,
                                         int64_t time_now) {
   int delay = in_quick_rampup_ ? kQuickRampUpDelayMs : current_rampup_delay_ms_;
   if (time_now < last_rampup_time_ms_ + delay)
     return false;
 
   return metrics.encode_usage_percent <
          options_.low_encode_usage_threshold_percent;
 }
 }  // namespace webrtc