Messages in this thread | | | Date | Fri, 19 Feb 2016 22:50:54 +0100 (CET) | From | Thomas Gleixner <> | Subject | Re: [PATCH v4 2/2] powercap/rapl: reduce ipi calls |
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On Fri, 19 Feb 2016, Jacob Pan wrote: > @@ -1380,6 +1375,7 @@ static int rapl_detect_topology(void) > int i; > int phy_package_id; > struct rapl_package *new_package, *rp; > + int lead_cpu; > > for_each_online_cpu(i) { > phy_package_id = topology_physical_package_id(i); > @@ -1392,7 +1388,11 @@ static int rapl_detect_topology(void) > /* add the new package to the list */ > new_package->id = phy_package_id; > new_package->nr_cpus = 1; > - > + /* find the first active cpu of the package */ > + lead_cpu = cpumask_any_and(topology_core_cpumask(i), > + cpumask_of(i));
Yuck. Why any_and? The result is i, simply because i is online otherwise you would not be there.
> + if (lead_cpu < nr_cpu_ids) > + new_package->lead_cpu = lead_cpu;
So the above is identical to
new_package->lead_cpu = lead_cpu;
Hmm?
> @@ -1500,6 +1503,15 @@ static int rapl_cpu_callback(struct notifier_block *nfb, > break; > if (--rp->nr_cpus == 0) > rapl_remove_package(rp); > + else if (cpu == rp->lead_cpu) { > + /* choose another active cpu in the package */ > + lead_cpu = cpumask_any_but(topology_core_cpumask(cpu), cpu);
This part is correct.
Thanks,
tglx
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