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Commit 90a5d5af authored by Konstantin Khlebnikov's avatar Konstantin Khlebnikov Committed by Linus Torvalds
Browse files

mm-tracepoint: fix documentation and examples 



We renamed the page-free mm tracepoints.

Signed-off-by: default avatarKonstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: default avatarMinchan Kim <minchan.kim@gmail.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent b413d48a

Documentation/trace/tracepoint-analysis.txt

+20 −20
Original line number Diff line number Diff line
@@ -93,14 +93,14 @@ By specifying the -a switch and analysing sleep, the system-wide events 
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
@@ -119,15 +119,15 @@ basis using set_ftrace_pid. 
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
@@ -146,8 +146,8 @@ to know what the standard deviation is. By and large, this is left to the 
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
@@ -157,8 +157,8 @@ occurrences are useful to the performance analyst, then perf can be used. 
   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% )
@@ -168,15 +168,15 @@ aggregation of discrete events, then a script would need to be developed. 
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% )
@@ -220,8 +220,8 @@ were generating events within the kernel. To begin this sort of analysis, the 
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) ]
@@ -260,8 +260,8 @@ noticed that X was generating an insane amount of page allocations so let's look 
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

tools/perf/Documentation/examples.txt

+17 −17
Original line number Diff line number Diff line
@@ -17,8 +17,8 @@ titan:~> perf list 
  kmem:kmem_cache_alloc_node               [Tracepoint event]

  kmem:kfree                               [Tracepoint event]

  kmem:kmem_cache_free                     [Tracepoint event]

  kmem:mm_page_free_direct                 [Tracepoint event]

  kmem:mm_pagevec_free                     [Tracepoint event]

  kmem:mm_page_free                        [Tracepoint event]

  kmem:mm_page_free_batched                [Tracepoint event]

  kmem:mm_page_alloc                       [Tracepoint event]

  kmem:mm_page_alloc_zone_locked           [Tracepoint event]

  kmem:mm_page_pcpu_drain                  [Tracepoint event]
@@ -29,15 +29,15 @@ measured. For example the page alloc/free properties of a 'hackbench 
run' are:



 titan:~> perf stat -e kmem:mm_page_pcpu_drain -e kmem:mm_page_alloc

 -e kmem:mm_pagevec_free -e kmem:mm_page_free_direct ./hackbench 10

 -e kmem:mm_page_free_batched -e kmem:mm_page_free ./hackbench 10

 Time: 0.575



 Performance counter stats for './hackbench 10':



          13857  kmem:mm_page_pcpu_drain

          27576  kmem:mm_page_alloc

           6025  kmem:mm_pagevec_free

          20934  kmem:mm_page_free_direct

           6025  kmem:mm_page_free_batched

          20934  kmem:mm_page_free



    0.613972165  seconds time elapsed
@@ -45,8 +45,8 @@ You can observe the statistical properties as well, by using the 
'repeat the workload N times' feature of perf stat:



 titan:~> perf stat --repeat 5 -e kmem:mm_page_pcpu_drain -e

   kmem:mm_page_alloc -e kmem:mm_pagevec_free -e

   kmem:mm_page_free_direct ./hackbench 10

   kmem:mm_page_alloc -e kmem:mm_page_free_batched -e

   kmem:mm_page_free ./hackbench 10

 Time: 0.627

 Time: 0.644

 Time: 0.564
@@ -57,8 +57,8 @@ You can observe the statistical properties as well, by using the 


          12920  kmem:mm_page_pcpu_drain    ( +-   3.359% )

          25035  kmem:mm_page_alloc         ( +-   3.783% )

           6104  kmem:mm_pagevec_free       ( +-   0.934% )

          18376  kmem:mm_page_free_direct   ( +-   4.941% )

           6104  kmem:mm_page_free_batched  ( +-   0.934% )

          18376  kmem:mm_page_free	    ( +-   4.941% )



    0.643954516  seconds time elapsed   ( +-   2.363% )
@@ -158,15 +158,15 @@ Or you can observe the whole system's page allocations for 10 
seconds:



titan:~/git> perf stat -a -e kmem:mm_page_pcpu_drain -e

kmem:mm_page_alloc -e kmem:mm_pagevec_free -e

kmem:mm_page_free_direct sleep 10

kmem:mm_page_alloc -e kmem:mm_page_free_batched -e

kmem:mm_page_free sleep 10



 Performance counter stats for 'sleep 10':



         171585  kmem:mm_page_pcpu_drain

         322114  kmem:mm_page_alloc

          73623  kmem:mm_pagevec_free

         254115  kmem:mm_page_free_direct

          73623  kmem:mm_page_free_batched

         254115  kmem:mm_page_free



   10.000591410  seconds time elapsed
@@ -174,15 +174,15 @@ Or observe how fluctuating the page allocations are, via statistical 
analysis done over ten 1-second intervals:



 titan:~/git> perf stat --repeat 10 -a -e kmem:mm_page_pcpu_drain -e

   kmem:mm_page_alloc -e kmem:mm_pagevec_free -e

   kmem:mm_page_free_direct sleep 1

   kmem:mm_page_alloc -e kmem:mm_page_free_batched -e

   kmem:mm_page_free sleep 1



 Performance counter stats for 'sleep 1' (10 runs):



          17254  kmem:mm_page_pcpu_drain    ( +-   3.709% )

          34394  kmem:mm_page_alloc         ( +-   4.617% )

           7509  kmem:mm_pagevec_free       ( +-   4.820% )

          25653  kmem:mm_page_free_direct   ( +-   3.672% )

           7509  kmem:mm_page_free_batched  ( +-   4.820% )

          25653  kmem:mm_page_free	    ( +-   3.672% )



    1.058135029  seconds time elapsed   ( +-   3.089% )