Manuel Selva <selva.man...@gmail.com> writes: > > + It seems impossible to have per thread mode with this uncore > event. I have to specify the -a or the -C option to the perf tool to > get some results. Looking at the perf_event_open system call happening > behind the scene, and calling it myself from code, I noticed that the > call succeeded only when the pid parameter is -1 and the cpu one is > different from -1. I guess that per thread counting is not available > for uncore events because it's impossible for the hardware to measure > only the uncore events generated by a given thread (because by > definition uncore is shared by all the cores associated to it) Am I > right ?
Yes uncore counting is per socket counting. > > + How the cpu parameter to perf_event_open should be interpreted for > uncore events ? On my platform I have 12 cores (my two cpus are hexa > core ones and hyper threading is disabled). Does providing a cpu value > of 5 to the system call along with an uncore event means counting the > events on the uncore associated to the core 5 ? Yes, the socket associated with the CPU is used. -Andi -- a...@linux.intel.com -- Speaking for myself only -- To unsubscribe from this list: send the line "unsubscribe linux-perf-users" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
