1PERFALLOC(1)                General Commands Manual               PERFALLOC(1)
2
3
4

NAME

6       perfalloc - notify pmdaperfevent(1) to disable hardware counter alloca‐
7       tion.
8

SYNOPSIS

10       $PCP_PMDAS_DIR/perfevent/perfalloc [-D] [-d] [-f  lockfile]  [-h]  [-v]
11       [COMMAND]
12

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.
17
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.
22
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).
25
26       If  a  commandline  is  given,  this is executed as a subprocess of the
27       agent.  When the command dies, so does the agent.
28
29       A brief description of the command line options follows:
30
31       -D   run in the foreground (the default)
32
33       -d   run in the background
34
35       -f FILE
36            use FILE as the lock file  (default  $PCP_PMDAS_DIR/perfevent/per‐
37            flock)
38
39       -h   display a help message and exit
40
41       -v   output version number and exit
42

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.
47
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.
51

SEE ALSO

53       pmdaperfevent(1), perfevent.conf(3) and sysctl(8).
54
55
56
57Performance Co-Pilot                  PCP                         PERFALLOC(1)
Impressum