tjh.dev
powerpc/mm: Add trace point for tracking hash pte fault
This enables us to understand how many hash fault we are taking
when running benchmarks.
For ex:
-bash-4.2# ./perf stat -e powerpc:hash_fault -e page-faults /tmp/ebizzy.ppc64 -S 30 -P -n 1000
...
Performance counter stats for '/tmp/ebizzy.ppc64 -S 30 -P -n 1000':
1,10,04,075 powerpc:hash_fault
1,10,03,429 page-faults
30.865978991 seconds time elapsed
NOTE:
The impact of the tracepoint was not noticeable when running test. It was
within the run-time variance of the test. For ex:
without-patch:
--------------
Performance counter stats for './a.out 3000 300':
643 page-faults # 0.089 M/sec
7.236562 task-clock (msec) # 0.928 CPUs utilized
2,179,213 stalled-cycles-frontend # 0.00% frontend cycles idle
17,174,367 stalled-cycles-backend # 0.00% backend cycles idle
0 context-switches # 0.000 K/sec
0.007794658 seconds time elapsed
And with-patch:
---------------
Performance counter stats for './a.out 3000 300':
643 page-faults # 0.089 M/sec
7.233746 task-clock (msec) # 0.921 CPUs utilized
0 context-switches # 0.000 K/sec
0.007854876 seconds time elapsed
Performance counter stats for './a.out 3000 300':
643 page-faults # 0.087 M/sec
649 powerpc:hash_fault # 0.087 M/sec
7.430376 task-clock (msec) # 0.938 CPUs utilized
2,347,174 stalled-cycles-frontend # 0.00% frontend cycles idle
17,524,282 stalled-cycles-backend # 0.00% backend cycles idle
0 context-switches # 0.000 K/sec
0.007920284 seconds time elapsed
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
authored by