Manual Pages for UNIX Operating System command usage for man cpc_disable

CPU Performance Counters Library Functions       cpc_enable(3CPC)



NAME
     cpc_enable, cpc_disable -  enable  and  disable  performance
     counters

SYNOPSIS
     cc [ flag... ] file... -lcpc [ library... ]
     #include 

     int cpc_enable(cpc_t *cpc);


     int cpc_disable(cpc_t *cpc);


DESCRIPTION
     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 exam-
     ined.  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.

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

ERRORS
     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.


EXAMPLES
     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.






SunOS 5.11          Last change: 31 Jan 2005                    1






CPU Performance Counters Library Functions       cpc_enable(3CPC)



     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 */
       }


ATTRIBUTES
     See attributes(5) for descriptions of the  following  attri-
     butes:



     ____________________________________________________________
    |       ATTRIBUTE TYPE        |       ATTRIBUTE VALUE       |
    |_____________________________|_____________________________|
    | Interface Stability         | Committed                   |
    |_____________________________|_____________________________|
    | MT-Level                    | Safe                        |
    |_____________________________|_____________________________|


SEE ALSO
     cputrack(1), cpc(3CPC), cpc_open(3CPC), libcpc(3LIB), attri-
     butes(5)












SunOS 5.11          Last change: 31 Jan 2005                    2