Difference between revisions of "Dtrace"

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(Created page with "== Some short cmds or one-liners around dtrace == '''ARC accesses by applicaiton''' <pre> # dtrace -n 'sdt:zfs::arc-hit,sdt:zfs::arc-miss { @[execname] = count() }' </pre> ...")
 
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found @[http://dtrace.org/blogs/brendan/2012/01/09/activity-of-the-zfs-arc/]
 
found @[http://dtrace.org/blogs/brendan/2012/01/09/activity-of-the-zfs-arc/]
 +
 +
'''what is really going on'''
 +
One nice example - everyone knows "man man" but what is really happening when this command is issued? Dtrace filtered on user id while typing man man on another terminal.
 +
<pre>
 +
root@vbox01:~# dtrace -n 'proc:::exec-success /uid == 100/ { trace(curpsinfo->pr_psargs); }'
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dtrace: description 'proc:::exec-success ' matched 1 probe
 +
CPU    ID                    FUNCTION:NAME
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  0    716        exec_common:exec-success  /usr/gnu/bin/tbl
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  0    716        exec_common:exec-success  /usr/bin/less -ins /tmp/mpTijdFb
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  1    716        exec_common:exec-success  man man
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  1    716        exec_common:exec-success  /usr/bin/troff -E -T ascii -mandoc
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  1    716        exec_common:exec-success  /usr/bin/mv -f /tmp/mpTijdFb /usr/share/man/cat1/man.1
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  2    716        exec_common:exec-success  /usr/bin/eqn -T ascii
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  3    716        exec_common:exec-success  /usr/bin/preconv -D latin-1 /usr/share/man/man1/man.1
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  3    716        exec_common:exec-success  /usr/bin/grotty -c
 +
^C
 +
</pre>

Revision as of 13:28, 4 February 2020

Some short cmds or one-liners around dtrace

ARC accesses by applicaiton

# dtrace -n 'sdt:zfs::arc-hit,sdt:zfs::arc-miss { @[execname] = count() }'


found @[1]

what is really going on One nice example - everyone knows "man man" but what is really happening when this command is issued? Dtrace filtered on user id while typing man man on another terminal.

root@vbox01:~# dtrace -n 'proc:::exec-success /uid == 100/ { trace(curpsinfo->pr_psargs); }'
dtrace: description 'proc:::exec-success ' matched 1 probe
 CPU     ID                    FUNCTION:NAME
   0    716         exec_common:exec-success   /usr/gnu/bin/tbl
   0    716         exec_common:exec-success   /usr/bin/less -ins /tmp/mpTijdFb
   1    716         exec_common:exec-success   man man
   1    716         exec_common:exec-success   /usr/bin/troff -E -T ascii -mandoc
   1    716         exec_common:exec-success   /usr/bin/mv -f /tmp/mpTijdFb /usr/share/man/cat1/man.1
   2    716         exec_common:exec-success   /usr/bin/eqn -T ascii
   3    716         exec_common:exec-success   /usr/bin/preconv -D latin-1 /usr/share/man/man1/man.1
   3    716         exec_common:exec-success   /usr/bin/grotty -c
^C