PMC_ATTACH(3)

NAME
pmc_attach, pmc_detach - attaching and detaching process scope PMCs to target processes

LIBRARY
libpmc

SYNOPSIS
#include <pmc.h>
int
pmc_attach(pmc_id_t pmcid, pid_t pid);
int
pmc_detach(pmc_id_t pmcid, pid_t pid);

DESCRIPTION
These functions control the set of target processes tracked by a process scope PMC.

Function pmc_attach() is used to attach a process scope PMC specified by argument pmcid to a target process specified by argument pid. Argument pid may be zero to denote the current process. If the PMC was allocated with modifier PMC_F_DESCENDANTS, the PMC will additionally attach to current and future descendents of the specified target process. The PMC should be in a quiescent state (i.e., not running).

Function pmc_detach() is used to detach a process scope PMC specified by argument pmcid from a process specified by argument pid. Argument pid may be zero to denote the current process.

RETURN VALUES

ERRORS
A call to function pmc_attach() may fail with the following errors:

[EBUSY]
    Argument pmcid specified a PMC that was not in a quiescent state.

[EBUSY]
    The target process specified by function pmc_attach is being tracked by another process scope PMC that uses the same PMC hardware resources.

[EEXIST]
    The target process is already being tracked by the specified PMC.

[EINVAL]
    Argument pmcid specified a PMC with system scope.

[EINVAL]
    Argument pid specified an illegal process id.

[EINVAL]
    The current process does not own a PMC with the handle specified in argument pmcid.

[EPERM]
    The caller lacked the privilege needed to attach PMCs to the specified target process.

[EPERM]
    (i386 and amd64 architectures) The PMC specified by argument pmcid has been setup to allow the use of the RDPMC instruction for self measurement.

[ESRCH]
    The current process does not own any PMCs.

[ESRCH]
    The process specified by argument pid did not exist.

A call to function pmc_detach() may fail with the following errors:

[EINVAL]
    Argument pmcid specified a PMC with system scope.

[EINVAL]
    Argument pid specified an illegal process id.

[EINVAL]
    The current process does not own a PMC with the handle specified in argument pmcid.

[EINVAL]
    The specified PMC was not attached to the target process.

[ESRCH]
    The current process does not own any PMCs.

[ESRCH]
    The process specified by argument pid is not being monitored by hwpmc(4).

[ESRCH]
    The process specified by argument pid did not exist.

SEE ALSO
pmc(3), pmc_start(3), pmc_stop(3), hwpmc(4)