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
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
use FILE as the lock file (default
-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.
This page is part of the PCP (Performance Co-Pilot) project.
Information about the project can be found at ⟨http://www.pcp.io/⟩.
If you have a bug report for this manual page, send it to
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Performance Co-Pilot PCP PERFALLOC(1)