On 3 June 2014 15:22, Morten Rasmussen <morten.rasmus...@arm.com> wrote: > On Fri, May 23, 2014 at 04:52:58PM +0100, Vincent Guittot wrote: >> power_orig is only changed for system with a SMT sched_domain level in order >> to >> reflect the lower capacity of CPUs. Heterogenous system also have to reflect >> an >> original capacity that is different from the default value. >> >> Create a more generic function arch_scale_cpu_power that can be also used by >> non SMT platform to set power_orig. > > I did a quick test of the patch set with adjusting cpu_power on > big.LITTLE (ARM TC2) to reflect the different compute capacities of the > A15s and A7s. I ran the sysbench cpu benchmark with 5 threads with and > without the patches applied, but with non-default cpu_powers. > > I didn't see any difference in the load-balance. Three tasks ended up on > the two A15s and two tasks ended up on two of the three A7s leaving one > unused in both cases. > > Using default cpu_power I get one task on each of the five cpus (best > throughput). Unless I messed something up, it seems that setting > cpu_power doesn't give me the best throughput with these patches > applied.
That's normal this patchset is necessary but not enough to solve the issue you mention. We also need to fix the way the imbalance is calculated for such situation. I have planned to push that in another patchset in order to not mix too much thing together Vincent > > Have you done any tests on big.LITTLE? > > Morten -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/