for a duration of time can be examined.
$ perf stat -a \
- -e kmem:mm_page_alloc -e kmem:mm_page_free_direct \
- -e kmem:mm_pagevec_free \
+ -e kmem:mm_page_alloc -e kmem:mm_page_free \
+ -e kmem:mm_page_free_batched \
sleep 10
Performance counter stats for 'sleep 10':
9630 kmem:mm_page_alloc
- 2143 kmem:mm_page_free_direct
- 7424 kmem:mm_pagevec_free
+ 2143 kmem:mm_page_free
+ 7424 kmem:mm_page_free_batched
10.002577764 seconds time elapsed
Events can be activated and tracked for the duration of a process on a local
basis using PCL such as follows.
- $ perf stat -e kmem:mm_page_alloc -e kmem:mm_page_free_direct \
- -e kmem:mm_pagevec_free ./hackbench 10
+ $ perf stat -e kmem:mm_page_alloc -e kmem:mm_page_free \
+ -e kmem:mm_page_free_batched ./hackbench 10
Time: 0.909
Performance counter stats for './hackbench 10':
17803 kmem:mm_page_alloc
- 12398 kmem:mm_page_free_direct
- 4827 kmem:mm_pagevec_free
+ 12398 kmem:mm_page_free
+ 4827 kmem:mm_page_free_batched
0.973913387 seconds time elapsed
performance analyst to do it by hand. In the event that the discrete event
occurrences are useful to the performance analyst, then perf can be used.
- $ perf stat --repeat 5 -e kmem:mm_page_alloc -e kmem:mm_page_free_direct
- -e kmem:mm_pagevec_free ./hackbench 10
+ $ perf stat --repeat 5 -e kmem:mm_page_alloc -e kmem:mm_page_free
+ -e kmem:mm_page_free_batched ./hackbench 10
Time: 0.890
Time: 0.895
Time: 0.915
Performance counter stats for './hackbench 10' (5 runs):
16630 kmem:mm_page_alloc ( +- 3.542% )
- 11486 kmem:mm_page_free_direct ( +- 4.771% )
- 4730 kmem:mm_pagevec_free ( +- 2.325% )
+ 11486 kmem:mm_page_free ( +- 4.771% )
+ 4730 kmem:mm_page_free_batched ( +- 2.325% )
0.982653002 seconds time elapsed ( +- 1.448% )
Using --repeat, it is also possible to view how events are fluctuating over
time on a system-wide basis using -a and sleep.
- $ perf stat -e kmem:mm_page_alloc -e kmem:mm_page_free_direct \
- -e kmem:mm_pagevec_free \
+ $ perf stat -e kmem:mm_page_alloc -e kmem:mm_page_free \
+ -e kmem:mm_page_free_batched \
-a --repeat 10 \
sleep 1
Performance counter stats for 'sleep 1' (10 runs):
1066 kmem:mm_page_alloc ( +- 26.148% )
- 182 kmem:mm_page_free_direct ( +- 5.464% )
- 890 kmem:mm_pagevec_free ( +- 30.079% )
+ 182 kmem:mm_page_free ( +- 5.464% )
+ 890 kmem:mm_page_free_batched ( +- 30.079% )
1.002251757 seconds time elapsed ( +- 0.005% )
data must be recorded. At the time of writing, this required root:
$ perf record -c 1 \
- -e kmem:mm_page_alloc -e kmem:mm_page_free_direct \
- -e kmem:mm_pagevec_free \
+ -e kmem:mm_page_alloc -e kmem:mm_page_free \
+ -e kmem:mm_page_free_batched \
./hackbench 10
Time: 0.894
[ perf record: Captured and wrote 0.733 MB perf.data (~32010 samples) ]
at it:
$ perf record -c 1 -f \
- -e kmem:mm_page_alloc -e kmem:mm_page_free_direct \
- -e kmem:mm_pagevec_free \
+ -e kmem:mm_page_alloc -e kmem:mm_page_free \
+ -e kmem:mm_page_free_batched \
-p `pidof X`
This was interrupted after a few seconds and