From 7c21e0b6b184e4dd0b7e119f470089a4149b6e2d Mon Sep 17 00:00:00 2001
From: gineshidalgo99 <gineshidalgo99@gmail.com>
Date: Thu, 5 Jul 2018 12:17:45 -0400
Subject: [PATCH] CPU works less if queues are full or empty

---
 doc/release_notes.md                            | 1 +
 include/openpose/thread/subThreadQueueIn.hpp    | 5 ++++-
 include/openpose/thread/subThreadQueueInOut.hpp | 5 +++++
 include/openpose/thread/subThreadQueueOut.hpp   | 3 +++
 4 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/doc/release_notes.md b/doc/release_notes.md
index 58e1c727d..62e7e1b4b 100644
--- a/doc/release_notes.md
+++ b/doc/release_notes.md
@@ -243,6 +243,7 @@ OpenPose Library - Release Notes
     18. Speed up of cvMatToOpOutput and opOutputToCvMat: op::Datum::outputData is now H x W x C instead of C x H x W, making it much faster to be copied to/from op::Datum::cvOutputData.
     19. Much faster GUI display by adding the `WITH_OPENCV_WITH_OPENGL` flag to tell whether to use OpenGL support for OpenCV.
     20. Turned security check error into warning when using dynamic `net_resolution` for `image_dir` in CPU/OpenCL versions.
+    21. Minimized CPU usage when queues are empty or full, in order to prevent problems such as general computer slow down, overheating, or excesive power usage.
 2. Functions or parameters renamed:
     1. Removed scale parameter from hand and face rectangle extractor (causing wrong results if custom `--output_resolution`).
     2. Functions `scaleKeypoints`, other than `scaleKeypoints(Array<float>& keypoints, const float scale)`, renamed as `scaleKeypoints2d`.
diff --git a/include/openpose/thread/subThreadQueueIn.hpp b/include/openpose/thread/subThreadQueueIn.hpp
index b2e3df831..3786426f8 100644
--- a/include/openpose/thread/subThreadQueueIn.hpp
+++ b/include/openpose/thread/subThreadQueueIn.hpp
@@ -31,7 +31,8 @@ namespace op
 namespace op
 {
     template<typename TDatums, typename TWorker, typename TQueue>
-    SubThreadQueueIn<TDatums, TWorker, TQueue>::SubThreadQueueIn(const std::vector<TWorker>& tWorkers, const std::shared_ptr<TQueue>& tQueueIn) :
+    SubThreadQueueIn<TDatums, TWorker, TQueue>::SubThreadQueueIn(const std::vector<TWorker>& tWorkers,
+                                                                 const std::shared_ptr<TQueue>& tQueueIn) :
         SubThread<TDatums, TWorker>{tWorkers},
         spTQueueIn{tQueueIn}
     {
@@ -44,6 +45,8 @@ namespace op
         try
         {
             // Pop TDatums
+            if (spTQueueIn->empty())
+                std::this_thread::sleep_for(std::chrono::microseconds{100});
             TDatums tDatums;
             bool queueIsRunning = spTQueueIn->tryPop(tDatums);
             // Check queue not empty
diff --git a/include/openpose/thread/subThreadQueueInOut.hpp b/include/openpose/thread/subThreadQueueInOut.hpp
index ce6310c22..edf44fc41 100644
--- a/include/openpose/thread/subThreadQueueInOut.hpp
+++ b/include/openpose/thread/subThreadQueueInOut.hpp
@@ -61,6 +61,8 @@ namespace op
                 if (!spTQueueOut->isFull())
                 {
                     // Pop TDatums
+                    if (spTQueueIn->empty())
+                        std::this_thread::sleep_for(std::chrono::microseconds{100});
                     TDatums tDatums;
                     bool workersAreRunning = spTQueueIn->tryPop(tDatums);
                     // Check queue not stopped
@@ -83,7 +85,10 @@ namespace op
                     return workersAreRunning;
                 }
                 else
+                {
+                    std::this_thread::sleep_for(std::chrono::microseconds{100});
                     return true;
+                }
             }
         }
         catch (const std::exception& e)
diff --git a/include/openpose/thread/subThreadQueueOut.hpp b/include/openpose/thread/subThreadQueueOut.hpp
index 289aefbb2..bd02480c2 100644
--- a/include/openpose/thread/subThreadQueueOut.hpp
+++ b/include/openpose/thread/subThreadQueueOut.hpp
@@ -68,7 +68,10 @@ namespace op
                     return workersAreRunning;
                 }
                 else
+                {
+                    std::this_thread::sleep_for(std::chrono::microseconds{100});
                     return true;
+                }
             }
         }
         catch (const std::exception& e)