common/Cycles.cc: skip initialization if rdtsc is not implemented

The Cycles initialization gets stuck in infinite loop if rdtsc is not
implemented. This patch fixes the issue by quitting the initialization
if rtdsc fails.

The patch was cherry-picked from ubuntu patch by James Page, see

https://bugzilla.redhat.com/show_bug.cgi?id=1222286

for more details on the patch.

Signed-off-by: James Page <james.page@ubuntu.com>

diff --git a/src/common/Cycles.cc b/src/common/Cycles.cc
index a2efcf34b8f3aa194fc3617e826f0ae51a2a911f..b0b687e49d46b3d3ea1c4bfac449ecfd5950957d 100644 (file)
--- a/src/common/Cycles.cc
+++ b/src/common/Cycles.cc
@@ -52,6 +52,10 @@ void Cycles::init()
   if (cycles_per_sec != 0)
     return;
 
+  // Skip initialization if rtdsc is not implemented
+  if (rdtsc() == 0)
+    return;
+
   // Compute the frequency of the fine-grained CPU timer: to do this,
   // take parallel time readings using both rdtsc and gettimeofday.
   // After 10ms have elapsed, take the ratio between these readings.