xref: /netbsd-src/external/cddl/dtracetoolkit/dist/Examples/anonpgpid_example.txt (revision c29d51755812ace2e87aeefdb06cb2b4dac7087a)
1The following is a demonstration of the anonpgpid.d script,
2
3
4Here we run it on a system that is implementing memory caps using the
5resource capping daemon, "rcapd",
6
7   # anonpgpid.d
8   Tracing... Hit Ctrl-C to end.
9   ^C
10      PID CMD              D BYTES
11     6215 bash             R 8192
12     6215 bash             W 126976
13     5809 rcapd            R 245760
14     6222 memleak.pl       R 974848
15     6222 memleak.pl       W 3055616
16
17The "memleak.pl" process consumes memory, and we can see above that it has
18encountered both reads and writes to the physical swap device - it is being
19paged out. A bash shell was also effected (which was in the same project that
20rcapd was monitoring).
21
22
23
24The following is an ordinary system that is very low on memory,
25
26   # anonpgpid.d
27   Tracing... Hit Ctrl-C to end.
28   ^C
29      PID CMD              D BYTES
30    18885 sendmail         R 4096
31    18600 automountd       R 4096
32        1 init             R 4096
33     2456 inetd            R 8192
34    18546 nscd             R 8192
35     2400 bash             R 12288
36      217 utmpd            R 28672
37      221 ttymon           R 32768
38      210 sac              R 36864
39    18777 snmpd            R 49152
40    18440 init             R 49152
41       89 nscd             R 61440
42      318 syslogd          R 73728
43      487 snmpd            R 81920
44     2453 inetd            R 102400
45      165 in.routed        R 131072
46      294 automountd       R 135168
47      215 inetd            R 135168
48      187 rpcbind          R 204800
49       86 kcfd             R 290816
50        7 svc.startd       R 1015808
51        9 svc.configd      R 1478656
52        2 pageout          W 23453696
53
54The "pageout" process is responsible for writing all the anonymous memory
55pages to the physical swap device, and we can see from the above that it
56has written 23 Mb. When processes access anonymous memory that has been
57swapped out, a major fault occurs and the memory is paged back in; in this
58case we can trace the process that was effected, and from the above we can
59see that several processes have been effected by the memory pressure.
60The most is "svc.configd", which needed to page back in 1.4 Mb of anonymous
61memory.
62
63
64
65Sometimes anonpgpid.d doesn't help too much. Here we only have pageouts
66to the physical swap device and no pageins,
67
68   # anonpgpid.d
69   ^C
70      PID CMD              D BYTES
71        2 pageout          W 61083648
72
73Only pageout is identified.
74