in my current code, I use barriers for synchronization as well as the event counters to measure the clock cycles. The main idea is that at the beginning of the loop, I start the counter and at specific times inside the algorithm I only read the values into an array (to make sense of it later).
The approach works fine, but after the first barrier, some counters (depending on something, 3 to 6 cores) get stuck. Restarting them doesn't help. If I always stop/start the timers, they don't get stuck. All 16 cores run the exact same SREC file.
Is any interaction between barriers and event counters known? Why could a CLK-counter just stop counting?
Is there any information about barriers around? What is the overhead using them, I measured some 600 clocks when all cores are synchronous, but when running 5-6 barriers directly after each other, the timers only show zero differences (since reading a timer takes about 26 cycles, something is wrong there).
Best Regards,
SebastianStatistics: Posted by sebraa — Mon Jul 21, 2014 8:34 pm
]]>