Disparity in Semaphores' performance

sashti srinivasan svasn_rtems at yahoo.com
Mon Mar 1 04:43:29 UTC 2004


     I am writing a performance test-bench for posix
compliant operating systems.  In order to validate my
test-suite, I compared the results with tmtests
distributed with rtems.

     Here is a small set of results:
      tmtests               |      my posix tests
 rtems_semaphore_create(9)  |      sem_init (11 usec)
 rtems_semaphore_delete(10) |      sem_destroy(22

     Please guide me whether 12 microseconds
difference between destroying a rtems-semaphore and a
posix-semaphore is theoretically possible.

     In the tmtests, I find calls to functions
Read_timer, Timer_initialize.  I could not find them
in  any document.  Probably they are not
rtems-directives.  I hope Read_timer gives time in
microseconds.  Please correct me if I am wrong.

     In tsim, I find that the function gettimeofday()
returns a same value whenever it is called.  But on
posix bsp, it works.  Any special configuration is
required to get this working on tsim?


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