Re: [PATCH v4 2/2] powercap/rapl: reduce ipi calls
From: Thomas Gleixner <hidden>
Date: 2016-02-19 21:52:18
Also in:
lkml
On Fri, 19 Feb 2016, Jacob Pan wrote:
quoted hunk ↗ jump to hunk
@@ -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?
quoted hunk ↗ jump to hunk
@@ -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