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Message
From: Dimitriοs Orfanos<sirtimid@g...>
Date: Mon Feb 18 14:25:18 CET 2008
Subject: [openrisc] or1ksim 's question
Oh, and something else. I am not a maintainer of this project but I've
involved because of my university has put me an assignment(actually a
master thesis). So by reading the code of the or1ksim0.2.0 I have
concluded that there is no good measuring of cycles so I've done
something else. I've set on my own some CPI(clocks per instruction) and
with little scripting I can see which commands are executed (from the
executed.log) and how many times these commands are executed and I
calculate the total cycles of my own. For example I've set that the
"l.and" command uses 1 cycle if with my little script sees that there
are 3 "l.and" I measure 3*1 total cycles. The simulator uses a scheduler
which every n cycles tries to communicate with virtual devices that are
defined in the sim.cfg like keyboard, uart, etc . These cycles are also
added in the simulation cycles, so there is not so accurate. If you want
to use the simulator for cycle counting do something similar with me
make a little script and count the commands from the executed.log . If
you just want to use the simulator to run programs then you don't need
to count cycles.
DO
yueng wrote:
> I change the sim.cfg , mem read and write both delay 1.
> i run jpeg decode in the or1ksim
> the result is
> 310,200,242 cycles, 171,816,396 instructions
> compare with arm7 it use only 56,000,000 cycle, and 40,000,000 instructions
>
> i remember that i read or1ksim is about 90% cycle accurate somewhere,
> same jpeg decode C code ,why or1ksim use so many instructions? and so many
> cycles.
>
>
> thank you
>
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