SOS! A question about Nanosim that is off-topic, please forgive me!

SOS! A question about Nanosim that is off-topic, please forgive me!

Post by walal » Sun, 07 Dec 2003 05:30:55

Dear all,

I am urgently in need of your help and I was unable to find any Synopsys
newsgroup anywhere and the synthesis newsgroup is not active at all; I am
facing an urgent deadline, but Synopsys support guys did not respond to me
after I "entered a call" on their website for 6 days... I did get
confirmation letter which is automatically generated after I submitted my
"call for support"... I have also send reply to urge them to help me but no
one responded... seems the whole support team is on vacation...

My question is simple: how can Nanosim resume a broken simulation? Due to
several problems here, my simulation always broke:

1) the network is not stable and I am using NFS to write the simulation
output; once a network is temporially off, even 10 seconds, nanosim hang;
2) people working on workstation tends to restart in a university lab
environment from time to time;
3) due to some reason, nanosim itself is easily hang for large circuit

I have been working on this simulation for 1 month but the simulation always
broke... do any of you know how to let Nanosim resume a broken simulation at
that very point of termination?

Once again, please do not sniff at me as I am posting on a wrong place... I
am really in urgent need of your help; I just want to by chance to grab one
or two of you experts here to see if you had the similar experience before;
I am terribly sorry if this wrong-posting offended you, wasted your time,
wasted your energy, or ruinned your weekend... :=)

Thanks a lot, experts!


SOS! A question about Nanosim that is off-topic, please forgive me!

Post by B » Sun, 07 Dec 2003 06:32:14

one way to do this is to save on a periodic basis.
I myself don't use them, but look at the command save_ckt_state and
This does not answer exaclty your question. But in SOS case any
workaround may save you.


SOS! A question about Nanosim that is off-topic, please forgive me!

Post by walal » Sun, 07 Dec 2003 07:37:52

simulation at
place... I

Dear HTH,

thank you very much for your answer! but how about the simulations that are
currently stopping there? do you have any magic to resume simulation
starting from the current point? (before that I have not applied any
save_ckt_state or restore_ckt_state command... )

Thanks a lot,


SOS! A question about Nanosim that is off-topic, please forgive me!

Post by erikwant » Tue, 09 Dec 2003 05:34:37

don't think there is a way to start the sim again if you didn't use
the save/restore feature. Just run the sim again. Here is some more

The Save/Restore mechanism in TimeMill/PowerMill/NanoSim is used to
simulation state at specified points and restore subsequent
at the desired point without repeating the whole process again. The
mechanism of Save/Restore has greatly improved this feature by making
more efficient, flexible and stable.

1.0 Synopsys Solution Methodologies to Customer Needs
The primary advantages of the new feature are that it not only allows
save/restore during transient simulation, but it also allows
after the configuration file is read and after partitioning. It also
allows simulation changes such as running interactive commands
and stimulus changes in the restore simulation.

1.1 Multiple saves at different phases
You can save simulation data during different phases as follows.

Phase one: After reading configuration files
Phase two: After partitioning
Phase three: Transient simulation at specified times

Allowing save/restore at these phases of the simulation gives you
more flexibility and control over the restored simulation. For
instance, restoring after the config file read stage allows you to
apply commands like search_ckt_analog, set_acc_limit, and
specify output reporting like report_block_powr, or control
by command like set_stage_size. Restoring after partitioning, you can
control DC initialization with commands like set_node_ic or
Restoring during transient simulation, you can specify simulation
control parameters with commands like set_sim_esv/spd, modify device
by set_mos_length or set_mos_width or specify circuit diagnostics
limit_dcpath_search or report_ckt_dcpath. Some of the most commonly
used configuration commands are used in the following phases:

After reading configuration files.
set_elem_acc, set_node_esv/spd, set_vec_opt, report_block_powr

After Partitioning,
set_node_ic, set_dc_opt

Transient simulation
set_sim_esv/spd, print_node_v/logic, set_mos_length/width,
force_node_v/logic, rel_node_v/logic.

Save/restore Syntax:
save_ckt_state [ti=save_time_1] [ti=save_time_2...]
+ [phase=config|partition] [compress=0|1|2]
save_ckt_state [start=start_time] [end=end_time] [period=cycle_time]
compress= specifies the type of compression utility to create a
compressed save file.
0 no compression (default)
1 using UNIX compress utility
2 using gzip utility

Due to the process of compression, you will experience some delay
during the simulation. If disk space is not the critical issue, no
compression is recommended to get the best performance.

save_ckt_state phase=config ti=100ns compress=1
Saves state after the config file read phase and at time 100ns, and
compresses save files using UNIX compress utility
restore_ckt_state [ti=restore_time] [phase=config|partition]
[interactive=0|1] [save_file=save_file_name]

restore_ckt_state ti=100ns interactive=1
Restores circuit to a previously saved state, at time 100ns, and
interactive mode.

restore_ckt_state ti=100ns save_file=./save_dir/
Restore circuit at time 100ns, with save file ./save_dir/
Note: The user-defined save file capability is available for