cpc_enable(3CPC)														  cpc_enable(3CPC)

NAME

       cpc_enable, cpc_disable - enable and disable performance counters

SYNOPSIS

       cc [ flag... ] file... -lcpc [ library... ]
       #include <libcpc.h>

       int cpc_enable(cpc_t *cpc);

       int cpc_disable(cpc_t *cpc);

       In  certain applications, it can be useful to explicitly enable and disable performance counters at different times so that the performance
       of a critical algorithm can be examined. The cpc_enable() and cpc_disable() functions can be used to enable  and  disable  the  performance
       counters without otherwise disturbing the invoking LWP's performance hardware configuration.

       Upon successful completion, cpc_enable() and cpc_disable() return 0. Otherwise, they return -1 and set errno to indicate the error.

       These functions will fail if:

       EAGAIN	       The associated performance counter context has been invalidated by another process.

       EINVAL	       No performance counter context has been created for the calling LWP.

       Example 1: Use cpc_enable and cpc_disable to minimize code needed by application.

       In  the	following  example, the cpc_enable() and cpc_disable() functions are used to minimize the amount of code that needs to be added to
       the application. The cputrack(1) command can be used in conjunction with these  functions  to  provide  event  programming,  sampling,  and
       reporting facilities.

       If  the	application is instrumented in this way and then started by cputrack with the nouser flag set in the event specification, counting
       of user events will only be enabled around the critical code section of interest. If the program is run normally, no harm will ensue.

       int
       main(int argc, char *argv[])
       {
	  cpc_t *cpc = cpc_open(CPC_VER_CURRENT);
	   /* ... application code ... */

	  if (cpc != NULL)
		  (void) cpc_enable(cpc);

	   /* ==> Code to be measured goes here <== */

	  if (cpc != NULL)
		  (void) cpc_disable(cpc);

	   /* ... other application code */
       }

       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Interface Stability	     |Evolving			   |
       +-----------------------------+-----------------------------+
       |MT-Level		     |Safe			   |
       +-----------------------------+-----------------------------+

       cputrack(1), cpc(3CPC), cpc_open(3CPC), libcpc(3LIB), attributes(5)

								    31 Jan 2005 						  cpc_enable(3CPC)