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<== Date ==> <== Thread ==>

Subject: Re: CA Connect rates under RTEMS
From: Eric Norum <norume@aps.anl.gov>
To: wnolan@bnl.gov, tech-talk@aps.anl.gov
Date: 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 wnolan@bnl.gov







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                                 norume@aps.anl.gov
Advanced Photon Source                     Phone: (630) 252-4793
Argonne National Laboratory


Replies:
RE: CA Connect rates under RTEMS Jeff Hill
Re: CA Connect rates under RTEMS (vxWorks, too) Kate Feng
References:
CA Connect rates under RTEMS wnolan

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