perfalloc - notify
pmdaperfevent(1) to disable hardware counter
allocation.
$PCP_PMDAS_DIR/perfevent/perfalloc [
-D] [
-d] [
-f
lockfile] [
-h] [
-v] [
COMMAND]
perfalloc is a command that notifies the
pmdaperfevent(1) to
disable hardware counter event collection. This allow unprivileged processes
to use the hardware counters.
If the reservation request fails, then perfalloc exits immediately with exit
code EXIT_FAILURE. If successful, the perfalloc will run until a kill signal
is received. The reservation request persists while perfalloc is running.
Note that
pmdaperfevent is affected by the value of the
kernel.perf_event_paranoid setting, which can be adjusted by
sysctl(8).
If a commandline is given, this is executed as a subprocess of the agent. When
the command dies, so does the agent.
A brief description of the command line options follows:
- -D
- run in the foreground (the default)
- -d
- run in the background
- -f FILE
- use FILE as the lock file (default
$PCP_PMDAS_DIR/perfevent/perflock)
- -h
- display a help message and exit
- -v
- output version number and exit
There may be a delay of up to 100 miliseconds between perfalloc requesting the
hardware counter disabling and the perfevent PMDA processing the request.
The perfalloc process does not check the status of the request and therefore is
not able to provide a positive confirmation that the request succeeded and the
hardware counters are disabled.
pmdaperfevent(1),
perfevent.conf(3) and
sysctl(8).