Re: [Adeos-main] switchbench tests with IPIPE tracer disabled

Wolfgang Grandegger Thu, 01 Feb 2007 05:39:59 -0800

Jan Kiszka wrote:

Wolfgang Grandegger wrote:
poornima r wrote:
Hi,
Thanks for the reply.

Linux version:linux-2.6.18
Xenomai: xenomai-2.3.0 (Stable version)
adeos patch: adeos-ipipe-2.6.18-ppc-1.5-01.patch
OK, I'm curious, did you use the vanilla kernel from kernel.org?
More comments below.
The tests were run as follows:
1)The sampling period in the code for latency and
switchbench was changed to 1000000000ns(to remove
overrun error) 2)switchtest was run with -n5 option
3)cyclictest was run with  -t5 option(5 threads were created.)
4)cyclictest was terminated with Illegal instruction
(after creating 5 threads) with IPIPE tracer enabled.
These were the results without I-PIPE Tracer option:
(All the tests were run without any load)
1)LATENCY TEST:-
User mode:-
/mnt/out_xen/bin# ./latency -t0
== Sampling period: 1000000 us
== Test mode: periodic user-mode task
== All results in microseconds
warming up...
RTT|  00:00:01  (periodic user-mode task, 1000000 us
period, priority 99)
RTH|-----lat min|-----lat avg|-----lat
max|-overrun|----lat best|---lat worst
RTD| 167.000| 167.000| 167.000| 0| 167.000|167.000RTD| 176.000| 176.000| 176.000| 0| 167.000|176.000RTD| 168.000| 168.000| 168.000| 0| 167.000|176.000RTD| 171.000| 171.000| 171.000| 0| 167.000|176.000
Kernel mode:-
[EMAIL PROTECTED]:/mnt/out_xen/bin# ./latency -t1
== Sampling period: 1000000 us
== Test mode: in-kernel periodic task
== All results in microseconds
warming up...
RTT|  00:00:00  (in-kernel periodic task, 1000000 us
period, priority 99)
RTH|-----lat min|-----lat avg|-----lat
max|-overrun|----lat best|---lat worst
RTD| 123.000| 123.000| 123.000| 0| 123.000|123.000RTD| 125.000| 125.000| 125.000| 0| 123.000|125.000RTD| 128.333| 128.333| 128.333| 0| 123.000|128.333RTD| 127.000| 127.000| 127.000| 0| 123.000|128.333
Interrupt mode:-
[EMAIL PROTECTED]:/mnt/out_xen/bin# ./latency -t2
== Sampling period: 1000000 us
== Test mode: in-kernel timer handler
== All results in microseconds
warming up...
RTT|  00:00:01  (in-kernel timer handler, 1000000 us
period, priority 99)
RTH|-----lat min|-----lat avg|-----lat
max|-overrun|----lat best|---lat worst
RTD| 45.334| 45.334| 45.334| 0| 45.334|45.334RTD| 45.000| 45.000| 45.000| 0| 45.000|45.334RTD| 46.000| 46.000| 46.000| 0| 45.000|46.000RTD| 47.334| 47.334| 47.334| 0| 45.000|47.334RTD| 46.334| 46.334| 46.334| 0| 45.000|47.334
I remember similar figures from measurements under 2.4. I guess you
tested without load!? Nevertheless, most of the latency is due to code
execution time because the system is very slow and the caches are small.
The sampling period is 1 second. I think "-p500" should already work.
2)CYCLICTEST RESULTS:-
[EMAIL PROTECTED]:/mnt/out_xen/bin# ./cyclictest -t5
5.14 3.71 1.72 6/31 216

T: 0 (    0) P:99 I:    1000 C:       0 Min: 1000000
Act:       0 Avg:       0 Max:-1000000
T: 1 (    0) P:98 I:    1500 C:       0 Min: 1000000
Act:       0 Avg:       0 Max:-1000000
T: 2 (  212) P:97 I:    2000 C:    8112 Min:     169
Act:     189 Avg:     204 Max:     288
T: 3 (    0) P:96 I:    2500 C:       0 Min: 1000000
Act:       0 Avg:       0 Max:-1000000
T: 4 (  216) P:95 I:    3000 C:   21596 Min:     180
Act:    1279 Avg:     702 Max:    1336
Hm, this looks bogus. What returns "./cyclictest" without options (or -t1)?
3)SWITCHBENCH TEST RESULTS:-
[EMAIL PROTECTED]:/mnt/out_xen/bin# ./switchbench -n5
== Sampling period: 1000000 us
== Do not interrupt this program
RTH|     lat min|     lat avg|     lat max|       lost
RTD|     229.333|      45.666|     229.333|          0

Test results with IPIPE tracer enabled
1)LATENCY TEST RESULTS:-
User mode:-
[EMAIL PROTECTED]:/mnt/out_xen/bin# ./latency -t0
== Sampling period: 1000000 us
== Test mode: periodic user-mode task
== All results in microseconds
warming up...
RTT|  00:00:01  (periodic user-mode task, 1000000 us
period, priority 99)
RTH|-----lat min|-----lat avg|-----lat
max|-overrun|----lat best|---lat worst
RTD| 340.000| 340.000| 340.000| 0| 340.000|340.000RTD| 338.666| 338.666| 338.666| 0| 338.666|340.000RTD| 341.000| 341.000| 341.000| 0| 338.666|341.000RTD| 342.000| 342.000| 342.000| 0| 338.666|342.000
2)kernel mode:-
[EMAIL PROTECTED]:/mnt/out_xen/bin# ./latency -t1
== Sampling period: 1000000 us
== Test mode: in-kernel periodic task
== All results in microseconds
warming up...
RTT|  00:00:00  (in-kernel periodic task, 1000000 us
period, priority 99)
RTH|-----lat min|-----lat avg|-----lat
max|-overrun|----lat best|---lat worst
RTD| 303.333| 303.333| 303.333| 0| 303.333|303.333RTD| 309.666| 309.666| 309.666| 0| 303.333|309.666RTD| 325.000| 325.000| 325.000| 0| 303.333|325.000RTD| 306.333| 306.333| 306.333| 0| 303.333|325.000
Interrupt mode:-
[EMAIL PROTECTED]:/mnt/out_xen/bin# ./latency -t2
== Sampling period: 1000000 us
== Test mode: in-kernel timer handler
== All results in microseconds
warming up...
RTT|  00:00:01  (in-kernel timer handler, 1000000 us
period, priority 99)
RTH|-----lat min|-----lat avg|-----lat
max|-overrun|----lat best|---lat worst
RTD| 153.334| 153.334| 153.334| 0| 153.334|153.334RTD| 154.667| 154.667| 154.667| 0| 153.334|154.667RTD| 164.334| 164.334| 164.334| 0| 153.334|164.334RTD| 154.667| 154.667| 154.667| 0| 153.334|164.334RTD| 163.667| 163.667| 163.667| 0| 153.334|164.334
The IPIPE tracer seems to add quit some code, Jan, does this look OK for
you?
I've seen almost 2 times higher numbers on an old Pentium I 133 MHz. But
I'm lacking information to relate this particular system to that values.
The increment appears to be fairly high.

It's a MPC860 at 50 MHz, I guess, which is slower than a Pentium I at133 MHz. The factor of 2 matches fine (= twice as as much code).

BTW, latests i-pipe patches for x86 now include a simple calibration
loop to estimate the minimum tracing overhead per function call. So,
when looking at a real trace, one might be able to asses the impact better.


Is it already in IPIPE v1.5?

Wolfgang.

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Re: [Adeos-main] switchbench tests with IPIPE tracer disabled

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