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Disabling skipping probes based on delays
- From: Darren Hart <dvhltc at us dot ibm dot com>
- To: systemtap at sourceware dot org
- Date: Wed, 27 Aug 2008 20:23:33 +0000
- Subject: Disabling skipping probes based on delays
I was hoping to use stap to simulate a scenario where only 25% of the
CPU is available to the system. The best way we came up with to do this
was to introduce a delay in the scheduler_tick. I have succeeded in
adding a udelay() into the scheduler_tick via guru mode and embedded C.
Unfortunately, stap bails out with the following message:
WARNING: Number of errors: 0, skipped probes: 103
I have tried running with:
-D STP_NO_OVERLOAD
and
-D STP_NO_OVERLOAD=1
but the same error results very shortly after loading the script. Is
there some way I can disable stap's internal delay accounting, allowing
me to introduce intentional delays?
--
Darren Hart
Real-Time Linux Team Lead
IBM Linux Technology Center