Hi all, I'm not sure if this is the correct place to ask this. I'm trying to get the branch miss-predict rate of an application using oprofile on an ARM cortex A8.
Due to the complexity of the ARM performance counters, I'm trying to write some simple test code to get performance counter results from, however I'm not entirely sure of how to do this. Ideally, I think that I would like to simply read/write to the PMCNT registers from usermode, which should be possible so long as it's turned on in the kernel. From reading some of the kernel code, it appears that this functionality is turned on when the PERF_EVENT_IOC_ENABLE ioctl is called, however I'm still getting an illegal instruction error, suggesting that this is not the case. The code that I currently have is located at https://gist.github.com/891812. If anybody could give me any pointers, it would be greatly appreciated. All the best, -- Nathan -- To unsubscribe from this list: send the line "unsubscribe linux-perf-users" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
