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powerpc/perf/imc: Fix nest events on muti socket system

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In a multi node system with discontiguous node ids, nest event values
are not showing up properly. eg. lscpu output:

  NUMA node0 CPU(s): 0-15
  NUMA node8 CPU(s): 16-31

Nest event values on such systems can be counted on CPUs <= 15:

  $./perf stat -e 'nest_powerbus0_imc/PM_PB_CYC/' -C 0-14 -I 1000 sleep 1000
  #           time             counts unit events
       1.000294577    30,17,24,42,880 nest_powerbus0_imc/PM_PB_CYC/

But not on CPUs >= 16:

  $./perf stat -e 'nest_powerbus0_imc/PM_PB_CYC/' -C 16-28 -I 1000 sleep 1000
  #           time             counts unit events
       1.000049902    <not supported> nest_powerbus0_imc/PM_PB_CYC/

This is because, when fetching the reference count, the node id (which
may be sparse) is used as the array index, not the node number (which
is 0 based and contiguous).

Fix it by using the node number as the array index.

  $./perf stat -e 'nest_powerbus0_imc/PM_PB_CYC/' -C 16-28 -I 1000 sleep 1000
  #           time             counts unit events
       1.000241961    26,12,35,28,704 nest_powerbus0_imc/PM_PB_CYC/

Signed-off-by: Anju T Sudhakar <anju@linux.vnet.ibm.com>
[mpe: Change log tweaks for clarity and brevity]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Anju T 2017-08-14 17:12:23 +05:30 committed by Michael Ellerman
parent 5b6c133e08
commit 7efbae9089
1 changed files with 1 additions and 1 deletions
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2
arch/powerpc/perf/imc-pmu.c
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@ -1064,7 +1064,7 @@ static int init_nest_pmu_ref(void)
*/
for_each_possible_cpu(cpu) {
nid = cpu_to_node(cpu);
for_each_online_node(i) {
for (i = 0; i < num_possible_nodes(); i++) {
if (nest_imc_refc[i].id == nid) {
per_cpu(local_nest_imc_refc, cpu) = &nest_imc_refc[i];
break;