[ag-automation] some stresstest results with Xenomai and Preempt-RT

[Wolfgang Grandegger]

Hello,

I'm trying to do similar test for the PowerPC Ocotea board. I was able 
to build and boot a RT-preempt kernel 2.6.16-rt13 (plus the patch at 
http://marc.theaimsgroup.com/?l=linux-kernel&m=114443684122525&w=2) for 
the Ocotea board and run cyclictest but I'm puzzled about the results. 
Without "-s" I get wired high latency figures increasing constantly over 
time. With "-s" I got under load (cache calibrator + ping flood):

   bash-3.00# ./cyclictest -n -s -c 1
   2.33 1.49 0.81 2/41 11245

   T: 0 (26879) P: 0 I:    1000 C: 97441 0 Min: 1333 Act: 3021 Max: 4736

I assume these numbers are "micro-seconds" but then 4.7 ms is a lot. 
Well, I'm not sure if RT preempt works properly. Maybe somebody could help.

Thanks.

Wolfgang.

Luotao Fu wrote:
> Hi folks,
> I'm following the example of ealier threads and thus open this thread in
> english :-) 
> I did some Stresstest with Pr-RT and Xenomai, in the
> following some simple results for evtl. further discussion:
> 
> Testcandidate:
> A: Preempt-RT 2.6.16-rt16
> B: Xenomai (svn Rev. #949)
> 
> Hardware:
> Intel Celeron 733MHz, 256 MB RAM, no SWAP. 
> 
> Testtools:
> * Cyclictest (originally by tglx, modified by Jan Kiszka, available at
>   the svn trunk of the xenomai project)
> * irLat (interrupt latency tool, based on the concept of LPPTEST by tglx,
> we'll release the tool soon)
> 
> used libraries/skins:
> A: NPTL
> B: POSIX Skin, RTDM Skin
> 
> (non-realtime) Workload:
> * cache calibrator (http://monetdb.cwi.nl/Calibrator/)
> * flood ping
> 
> Test duration:
> about 5 hours each
> 
> Results:
> * irLat:
>   |  Min(usec)  |  Max(usec)  
> A |  3.1985     |  105.33 
> B |  3.2130     |  92.52
> **********************************
> 
> * cyclictest:
> A:
> root at krachkiste:/ptx/work/lfu/utils/cyclictest ./cyclictest -p 80 -t 5 -n
> 1.58 1.61 1.62 3/68 4079
> 
> T: 0 ( 3131) P:80 I:    1000 C:16469865 Min:       8 Act:      35 Max: 192
> T: 1 ( 3132) P:79 I:    1500 C: 9979903 Min:       8 Act:      34 Max: 215
> T: 2 ( 3133) P:78 I:    2000 C: 7934887 Min:       9 Act:      38 Max: 123
> T: 3 ( 3134) P:77 I:    2500 C: 6587910 Min:       9 Act:      35 Max: 161
> T: 4 ( 3135) P:76 I:    3000 C: 5489925 Min:       9 Act:      57 Max: 186
> ______________________________________
> 
> B:
> root at krachkiste:/ptx/work/lfu/local/xenomai/testsuite/cyclic ./cyclictest -n -p 80 -t 5
> 1.16 1.05 1.01 2/43 4063
> 
> T: 0 ( 3381) P:80 I:    1000 C:17461866 Min:       1 Act:       7 Max: 151
> T: 1 ( 3382) P:79 I:    1500 C:11641244 Min:       1 Act:       7 Max: 223
> T: 2 ( 3383) P:78 I:    2000 C: 8730933 Min:       1 Act:      10 Max: 125
> T: 3 ( 3384) P:77 I:    2500 C: 6984747 Min:       1 Act:      10 Max: 134
> T: 4 ( 3385) P:76 I:    3000 C: 5820622 Min:       1 Act:       8 Max: 99
> 
> 
> Both systems show reliable results under heavy cache and interrupt workload. 
> Though the extreme values of testresults are quite near to each other,
> both candidates show quite different behaviour during the test. The
> presented results are just simple final results, in case
> of interest we'll post later some more detailed informations like plots,
> results of tracing/profiling, results of further benchmark tools etc.
> 
> P.S. 
> The Kernelconfiguration of both candidates are mostly identical.
> The configfiles, together with a list of running processes, are attached
> to this mail.
> 
> Cheers
> Luotao Fu
> 
> 
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