Re: [Gems-users] cpu-switch-time

["hongxia sun" <sunhx.seraph@xxxxxxxxx>]

Hi Shougata,

 

Because Simics is a function simulator, only one processor could run at a certain time. The parameter cpu-switch-time is used to switch Simics simulation time among multiprocessors.

If you set cpu-switch-time to 1000, Simics while switches from a processor to another processor each 1000 cycles. That means during these 1000 cycles, only this processor is running and sending memory transitions to ruby. While if you set cpu-switch-time to 1, Simics while switches among processor every cycle, thus the competition for a same cacheline will be much more intensely. Moreover, switching frequently among processors also need more time.

However, as I know, if you set cpu-switch-time to a high value, you cannot simulate the parallel operations of multiprocessor exactly.

It depends on your demand.

Best Regards,

Hongxia SUN

 

 

2007/1/4, Shougata Ghosh <shougata@xxxxxxxxxxxxx>:

Hi
How does the simulation time vary with cpu-switch-time? I'm running the
tm-deque (transactional microbenchmark) program with
MESI_SMP_LogTm_directory (Ruby only) and have set cpu-switch-time to 1.
It seems to be running extremely slow! Earlier, I had mistakenly run it
with cpu-switch-time set to 1000 (default) and it ran much faster.
Any ideas on this? I expected cpu-switch-time to affect the correctness
of transactional programs but not quite sure why it is slowing down
simulation time.
Thanks

_______________________________________________
Gems-users mailing list
Gems-users@xxxxxxxxxxx
https://lists.cs.wisc.edu/mailman/listinfo/gems-users
Use Google to search the GEMS Users mailing list by adding "site:https://lists.cs.wisc.edu/archive/gems-users/" to your search.