1PERFALLOC(1)                General Commands Manual               PERFALLOC(1)
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NAME

6       perfalloc - notify pmdaperfevent(1) to disable hardware counter alloca‐
7       tion.
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SYNOPSIS

10       $PCP_PMDAS_DIR/perfevent/perfalloc [-D] [-d] [-f  lockfile]  [-h]  [-v]
11       [COMMAND]
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DESCRIPTION

14       perfalloc  is  a  command that notifies the pmdaperfevent(1) to disable
15       hardware counter event collection.  This allow  unprivileged  processes
16       to use the hardware counters.
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18       If the reservation request fails, then perfalloc exits immediately with
19       exit code EXIT_FAILURE.  If successful, the perfalloc will run until  a
20       kill  signal  is received.  The reservation request persists while per‐
21       falloc is running.
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23       Note  that  pmdaperfevent  is  affected  by  the  value  of  the   ker‐
24       nel.perf_event_paranoid setting, which can be adjusted by sysctl(8).
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26       If  a  commandline  is  given,  this is executed as a subprocess of the
27       agent.  When the command dies, so does the agent.
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29       A brief description of the command line options follows:
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31       -D   run in the foreground (the default)
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33       -d   run in the background
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35       -f FILE
36            use FILE as the lock file  (default  $PCP_PMDAS_DIR/perfevent/per‐
37            flock)
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39       -h   display a help message and exit
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41       -v   output version number and exit
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BUGS

44       There  may  be  a  delay  of  up  to  100 miliseconds between perfalloc
45       requesting the hardware counter disabling and the perfevent  PMDA  pro‐
46       cessing the request.
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48       The  perfalloc  process  does  not  check the status of the request and
49       therefore is not able to  provide  a  positive  confirmation  that  the
50       request succeeded and the hardware counters are disabled.
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SEE ALSO

53       pmdaperfevent(1), perfevent.conf(3) and sysctl(8).
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57Performance Co-Pilot                  PCP                         PERFALLOC(1)
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