| Message ID | 1458274308.6622.79.camel@neuling.org (mailing list archive) |
|---|---|
| State | Superseded, archived |
| Headers | show |
On Fri, Mar 18, 2016 at 5:11 AM, Michael Neuling <mikey@neuling.org> wrote: > On Fri, 2016-03-18 at 15:04 +1100, Michael Neuling wrote: > >> On Wed, 2016-02-03 at 01:11 +0530, Shilpasri G Bhat wrote: >> > >> > cpu_to_chip_id() does a DT walk through to find out the chip id by >> > taking a contended device tree lock. This adds an unnecessary >> > overhead >> > in a hot path. So instead of calling cpu_to_chip_id() everytime >> > cache >> > the chip ids for all cores in the array 'core_to_chip_map' and use >> > it >> > in the hotpath. >> > >> > Reported-by: Anton Blanchard <anton@samba.org> >> > Signed-off-by: Shilpasri G Bhat <shilpa.bhat@linux.vnet.ibm.com> >> > Reviewed-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com> >> > Acked-by: Viresh Kumar <viresh.kumar@linaro.org> >> > --- >> > No changes from v7. >> >> How about this instead? It removes the linear lookup and seems a lot >> less complex. This has gone in already. Can you please send a patch on top of it? > BTW we never init nr_chips before using it. We also need something > like. > > diff --git a/drivers/cpufreq/powernv-cpufreq.c b/drivers/cpufreq/powernv-cpufreq.c > index d63d2cb..c819ed4 100644 > --- a/drivers/cpufreq/powernv-cpufreq.c > +++ b/drivers/cpufreq/powernv-cpufreq.c > @@ -556,6 +556,8 @@ static int init_chip_info(void) > unsigned int cpu, i; > unsigned int prev_chip_id = UINT_MAX; > > + nr_chips = 0; > + > for_each_possible_cpu(cpu) { > unsigned int id = cpu_to_chip_id(cpu); > > Including this part too maybe? Thanks, Rafael -- To unsubscribe from this list: send the line "unsubscribe linux-pm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/cpufreq/powernv-cpufreq.c b/drivers/cpufreq/powernv-cpufreq.c index d63d2cb..c819ed4 100644 --- a/drivers/cpufreq/powernv-cpufreq.c +++ b/drivers/cpufreq/powernv-cpufreq.c @@ -556,6 +556,8 @@ static int init_chip_info(void) unsigned int cpu, i; unsigned int prev_chip_id = UINT_MAX; + nr_chips = 0; + for_each_possible_cpu(cpu) { unsigned int id = cpu_to_chip_id(cpu);