Create one decode thread for each CPU

We can start creating more decoding threads now that we handle
rect ordering properly. No point in creating more threads than
there are CPUs though.

3 files changed, 44 insertions, 4 deletions

diff --git a/common/os/Thread.cxx b/common/os/Thread.cxx
index 7150a7f2..f38a10b7 100644
--- a/common/os/Thread.cxx
+++ b/common/os/Thread.cxx
@@ -20,6 +20,7 @@
 #include <windows.h>
 #else
 #include <pthread.h>
+#include <unistd.h>
 #endif
 
 #include <rdr/Exception.h>
@@ -99,6 +100,36 @@ bool Thread::isRunning()
   return running;
 }
 
+size_t Thread::getSystemCPUCount()
+{
+#ifdef WIN32
+  SYSTEM_INFO si;
+  size_t count;
+  DWORD mask;
+
+  GetSystemInfo(&si);
+
+  count = 0;
+  for (mask = si.dwActiveProcessorMask;mask != 0;mask >>= 1) {
+    if (mask & 0x1)
+      count++;
+  }
+
+  if (count > si.dwNumberOfProcessors)
+    count = si.dwNumberOfProcessors;
+
+  return count;
+#else
+  long ret;
+
+  ret = sysconf(_SC_NPROCESSORS_ONLN);
+  if (ret == -1)
+    return 0;
+
+  return ret;
+#endif
+}
+
 #ifdef WIN32
 long unsigned __stdcall Thread::startRoutine(void* data)
 #else
diff --git a/common/os/Thread.h b/common/os/Thread.h
index 41d94868..1a9aa54b 100644
--- a/common/os/Thread.h
+++ b/common/os/Thread.h
@@ -32,6 +32,9 @@ namespace os {
 
     bool isRunning();
 
+  public:
+    static size_t getSystemCPUCount();
+
   protected:
     virtual void worker() = 0;
 
diff --git a/common/rfb/DecodeManager.cxx b/common/rfb/DecodeManager.cxx
index ba2b2d2f..724cf215 100644
--- a/common/rfb/DecodeManager.cxx
+++ b/common/rfb/DecodeManager.cxx
@@ -38,7 +38,7 @@ static LogWriter vlog("DecodeManager");
 DecodeManager::DecodeManager(CConnection *conn) :
   conn(conn)
 {
-  int i;
+  size_t cpuCount;
 
   memset(decoders, 0, sizeof(decoders));
 
@@ -46,9 +46,15 @@ DecodeManager::DecodeManager(CConnection *conn) :
   producerCond = new os::Condition(queueMutex);
   consumerCond = new os::Condition(queueMutex);
 
-  // Just a single thread for now as we haven't sorted out the
-  // dependencies between rects
-  for (i = 0;i < 1;i++) {
+  cpuCount = os::Thread::getSystemCPUCount();
+  if (cpuCount == 0) {
+    vlog.error("Unable to determine the number of CPU cores on this system");
+    cpuCount = 1;
+  } else {
+    vlog.info("Detected %d CPU core(s) available for decoding", (int)cpuCount);
+  }
+
+  while (cpuCount--) {
     // Twice as many possible entries in the queue as there
     // are worker threads to make sure they don't stall
     freeBuffers.push_back(new rdr::MemOutStream());