Jens Axboe wrote on 03/03/2016 08:20 AM: > On Thu, Mar 03 2016, Sitsofe Wheeler wrote: >> On 3 March 2016 at 03:03, Vladislav Bolkhovitin <vst@xxxxxxxx> wrote: >>> For those who asked about perf profiling, it remained the same as before with the CPU >>> consumption is all about timekeeping and memset: >>> >>> - 55.74% fio fio [.] clock_thread_fn >>> clock_thread_fn >> >> Perhaps this is what is already included above but could you use the >> -g option on perf to collect it into a call-graph and post the top >> results? > > The above looks like a side effect of using gtod_cpu, it'll burn one > core. For the original poster - did you verify whether using gtod_cpu > was faster than using the CPU clock source in each CPU? Yes, I had verified it and mentioned in one of my reports. It slightly decreased the IOPS. I guess, it's a locking contention somewhere. Thanks, Vlad -- To unsubscribe from this list: send the line "unsubscribe fio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
