Add timeout for context queue pop. (#382)

Co-authored-by: Earle Lowe <e.lowe@chia.net>

src/cli.cpp

@@ -70,7 +70,7 @@ inline void InitDecompressorQueueDefault(bool no_cuda = false)
     if (initialized) {
         return;
     }
-    decompressor_context_queue.init(1, (uint32_t)std::thread::hardware_concurrency(), false, 9, !no_cuda, 0, false);
+    decompressor_context_queue.init(1, (uint32_t)std::thread::hardware_concurrency(), false, 9, !no_cuda, 0, false, 30);
     initialized = true;
 }
 

src/prover_disk.hpp

@@ -29,6 +29,7 @@
 #include <vector>
 #include <mutex>
 #include <condition_variable>
+#include <chrono>
 
 #include "../lib/include/picosha2.hpp"
 #include "calculate_bucket.hpp"
@@ -67,7 +68,8 @@ class ContextQueue {
         const uint32_t max_compression_level,
         bool use_gpu_harvesting,
         uint32_t gpu_index,
-        bool enforce_gpu_index
+        bool enforce_gpu_index,
+        uint16_t context_queue_timeout
     ) {
         assert(!_dcompressor_queue_initialized);
         _dcompressor_queue_initialized = true;
@@ -167,6 +169,7 @@ class ContextQueue {
                 }
             }
         }
+        this->context_queue_timeout = context_queue_timeout;
         return false;
     }
 
@@ -179,9 +182,24 @@ class ContextQueue {
 
     GreenReaperContext* pop() {
         std::unique_lock<std::mutex> lock(mutex);
-        while (queue.empty()) {
-            condition.wait(lock);
+
+        std::chrono::duration<double> wait_time = std::chrono::seconds(context_queue_timeout);
+
+        while (queue.empty() && wait_time.count() > 0) {
+            auto before_wait = std::chrono::steady_clock::now();
+
+            if (condition.wait_for(lock, wait_time) == std::cv_status::timeout) {
+                break;
+            }
+
+            auto elapsed = std::chrono::duration_cast<std::chrono::duration<double>>(std::chrono::steady_clock::now() - before_wait);
+            wait_time -= elapsed;
+        }
+
+        if (queue.empty()) {
+            throw std::runtime_error("Timeout waiting for context queue.");
         }
+
         GreenReaperContext* gr = queue.front();
         queue.pop();
         return gr;
@@ -191,6 +209,7 @@ class ContextQueue {
     std::queue<GreenReaperContext*> queue;
     std::mutex mutex;
     std::condition_variable condition;
+    uint16_t context_queue_timeout;
 };
 
 class ProofCache {
@@ -266,7 +285,8 @@ class ContextQueue {
         const uint32_t max_compression_level,
         bool use_gpu_harvesting,
         uint32_t gpu_index,
-        bool enforce_gpu_index
+        bool enforce_gpu_index,
+        uint16_t context_queue_timeout
     ) 
     {
         return false;