Experimental Physics and
Industrial Control System

Eric Norum <[email protected]> · Tue, 18 Jan 2005 12:33:15 -0600

wnolan wrote:

Hi all,
I was curious what sort or rates are being observed using the catime

utility for RTEMS installations. 
On a mvme2307 under RTEMS 4.6.2 running EPICS 3.14.6 I am seeing a

extream slowdown from our VX works installations and was wondering if it

was tyipical. 
--- Test data
Same Hardware

MVME2307

1x OMS VME58

1x Jerger VSC16

1x ACROMAG AVME9440

and process database( about 30 records ), no state programs running.
targeting a calc input field for 10000 connections.
VX-works gives
channel connect test

Elapsed Per Item = 0.00031412 sec, 3183.5 Items per sec, 1.8 Mbps

Search tries per chan - mean=1.010000 std dev=0.099499 min=1.000000

max=2.000000
RTEMS gives
channel connect test

Elapsed Per Item = 0.00358250 sec, 279.1 Items per sec, 0.2 Mbps

Search tries per chan - mean=2.210500 std dev=1.631377 min=1.000000

max=8.000000
-------------
I am also seeing the slowdown on ASYN Get tests
VX works seems to run about 6 Mbps where in the same test RTEMS is

running at about 1 Mbps 
A factor of 10 on channel connect and a factor of 6 on Asyn Get's 
Sync gets are running at about the same rate under both systems , just

under 1 Mbps 
Any help, Pointers or comparative data would be a help,
Bill Nolan
[email protected]

The RTEMS implementation of osiSufficentSpaceInPool calls malloc_free_space.
This turns out to be a very expensive operation. Take out the call to
malloc_free_space and the channel connect rate goes way up. I think that the
RTEMS maintainers have made malloc_free_space quite a bit quicker but the
change is still only in the RTEMS CVS repository.
BTW - the vxWorks implementation of osiSufficentSpaceInPool is of questionable
usefulness so it's not really clear to me that there's any point in using this
routine at all (Jeff Hill disagrees with me on this.....).
--
Eric Norum                                 [email protected]
Advanced Photon Source                     Phone: (630) 252-4793
Argonne National Laboratory

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System