Spectre: +multithread Does it work for sweeps?

Greetings all:

I am simulating (DC analysis) a simple digital circuit that has many
inputs (~20): there are 2^20 (~1000,000) DC runs using a data sweep.

DC runs are independent of each other. So +mt seems promissing to
speedup the simulation. What I observe though is that a 4 processor
machine and a single processor machine have very similar CPU times in
Spectre report.

Can Spectre +mt handle this? Is there a trick in netlisting to tell it
the DC runs are independent? Any way in general to exceute many DC
runs in parallel in a single Spectre call (provided a multiprocessor
host)?

Thanks for any hint in advance

Regards,

Hrh.

 

Can Spectre +mt handle this? Is there a trick in netlisting to tell it
the DC runs are independent? Any way in general to exceute many DC
runs in parallel in a single Spectre call (provided a multiprocessor
host)?

No, Spectre cannot run multiple DC analyses concurrently.
+mt makes devices to be evaluated in parallel which can yield some
speedup on a multiprocessor.

 

[Riad KACED]

Hi Hamid,

I'm afraid the MT does not apply in this case indeed ...
You said that you are simulating a digital design and don't see any
significant speedup when running on a 4-cpus machine.
You have to know that Spectre applies multithreading to evaluate the
model equations for bsim3v3/bsim4 devices and it needs 256 devices at
least to activate multithreading.
Check the circuit inventory in your logFile to see if you are in this
case ...

Good Luck !

Riad.