Hi,
This message was originally posted on the osol-code mailing list, but
someone suggested this is more appropriate for the performance community.
I am using a full-system simulator (Simics) on a simulated OpenSolaris
installation for a research project. The aim of the project is to implement
adaptive processor shutdown for energy savings.
We would like to measure the dependence of the interrupt latency (interrupt
response time) on the power state of a processor.
By adding a special ("magic") assembler instruction to the kernel code, we
can halt the simulation and consequently do memory reads/writes or execute
code in the simulator. I was thinking of adding such a magic instruction at
the beginning of the general interrupt code, and just before the execution
of the actual interrupt handler (for that specific interrupt). I could then
find a way of reading out current system time (I believe this is possible
from the simulator, otherwise I could maybe read out system time directly
from memory?).
Is this a correct approach?
I would thus add these magic instructions at line 63 (entry) and right
before lines 558 and 1181 (before the actual handler is called) referring to
http://src.opensolaris.org/source/xref/onnv/onnv-gate/usr/src/uts/sun4/ml/interrupt.s.
Is this correct?
In interrupt.s, I see that some kind of timestamp is saved before the
interrupt is called. What purpose does it serve, and where is it stored?
And where can I find a list and explanation of the different assembler
instructions that are used? This would be most useful to me!
Thank you, Thomas
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