diff --git a/src/steamcompmgr.cpp b/src/steamcompmgr.cpp
index b0e8e1a..8af16ec 100644
--- a/src/steamcompmgr.cpp
+++ b/src/steamcompmgr.cpp
@@ -32,6 +32,7 @@
 #include <thread>
 #include <condition_variable>
 #include <mutex>
+#include <atomic>
 #include <vector>
 
 #include <assert.h>
@@ -404,14 +405,18 @@ get_time_in_milliseconds (void)
 	return tv.tv_sec * 1000 + tv.tv_usec / 1000;
 }
 
-struct timeval lastvblankmsgtv;
-std::mutex lastvblankmsgtv_lock;
+uint64_t get_time_in_nanos()
+{
+	timespec ts;
+	clock_gettime(CLOCK_MONOTONIC_RAW, &ts);
+	return ts.tv_sec * 1000000000ul + ts.tv_nsec;
+}
+
+static std::atomic<uint64_t> g_lastvblank = { 0lu };
 
 void mark_vblank_message_time ( void )
 {
-	std::lock_guard<std::mutex> lock( lastvblankmsgtv_lock );
-
-	gettimeofday( &lastvblankmsgtv, NULL );
+	g_lastvblank = get_time_in_nanos();
 }
 
 static void
@@ -2828,18 +2833,12 @@ steamcompmgr_main (int argc, char **argv)
 
 					if ( ev.xclient.data.l[0] == 24 && ev.xclient.data.l[1] == 8 )
 					{
-						// Message from vblankmanager
-						std::lock_guard<std::mutex> lock( lastvblankmsgtv_lock );
-
-						struct timeval vblankmsgreceivedtv = {};
-						gettimeofday( &vblankmsgreceivedtv, nullptr );
-
-						struct timeval timediff = {};
-
-						timersub( &vblankmsgreceivedtv, &lastvblankmsgtv, &timediff );
+						uint64_t vblanktime = g_lastvblank;
+						uint64_t vblankreceived = get_time_in_nanos();
+						uint64_t diff = vblankreceived - vblanktime;
 
 						// give it 1 ms of slack.. maybe too long
-						if ( timediff.tv_sec != 0 || timediff.tv_usec > 1000 )
+						if ( diff > 1000000ul )
 						{
 							gpuvis_trace_printf( "ignored stale vblank\n" );
 						}