I'm trying to measure a native event on an AMD multicore machine (our 48-core romulus). The event name is "CPU_TO_DRAM_REQUESTS_TO_TARGET_NODE:*". There is no error if I start less than 5 threads, but then PAPI_read() starts to report errors if I have more threads (e.g., 6, 12 threads).
And here is the error information: Error in PAPI_read: PAPI_ESBST. BTW, I'm using PAPI 4.2.0.
Do you know what would be the reasons for the error?
This is strange. It's possible that that's a northbridge event; in that case it can only be used by one thread per core. I would think you'd be able to work on more than 5 threads though, I think you'd get at least 8. Are you pinning the threads to a CPU?