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

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
simulation...

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!

-Walala

 

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
restore_ckt_state.
This does not answer exaclty your question. But in SOS case any
workaround may save you.
HTH

 

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,

-Wlalal

 

I 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
infomation:

Introduction:
The Save/Restore mechanism in TimeMill/PowerMill/NanoSim is used to
save
simulation state at specified points and restore subsequent
simulations
at the desired point without repeating the whole process again. The
new
mechanism of Save/Restore has greatly improved this feature by making
it
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
save/restore
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
set_node_spd/esv,
specify output reporting like report_block_powr, or control
partitioning
by command like set_stage_size. Restoring after partitioning, you can
control DC initialization with commands like set_node_ic or
set_dc_opt.
Restoring during transient simulation, you can specify simulation
control parameters with commands like set_sim_esv/spd, modify device
size
by set_mos_length or set_mos_width or specify circuit diagnostics
using
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.

Example:
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]

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

restore_ckt_state ti=100ns save_file=./save_dir/out.save.100.000000ns
Restore circuit at time 100ns, with save file ./save_dir/
out.save.100.000000ns
Note: The user-defined save file capability is available for
2001.06-SP1
or later versions. The default save file is the one in the output
directory
defined in the nanosim command.

1.2 Changes allowed between Save and Restore
a. A complete list of interactive commands available for the restore
run can
be obtained by typing "help" at the interactive command prompt during
the
desired phase. The following is an example of the commands available:

i. Simulation control.
Force node values,
force_node_logic, force_node_v;
Change accuracy and speed setting,
set_sim_esv, set_sim_spd;
Ability to swap in an ADFMI model
swap_model_adfmi;

ii. Circuit modification
Freedom to change device size and value:
set_mos_length, set_mos_width, set_mos_minrdiff, set_node_cap,
set_resistor_value;

iii. Circuit diagnostic
Ability to start new diagnostics:
set_dcpath_thresh, report_block_power;

iv. Output
Ability to add signals to print, report:
print_node_logic, print_node_v, report_node_ic;

v. Execution control
handle_ckt_error; set_elem_break; set_node_break; set_time_break

vi. Interactive environment
delete_cmd_alias; limit_mesg_byidx; limit_mesg_byphase;
make_cmd_alias; read_cmd_file; set_cmd_env;
set_cmd_mode; set_mesg_opt; set_sim_unit;

vii Miscellaneous
Ability to change frequency to print report
set_sim_tup
b. -cr/CR command line options to execute an interactive command file
for
a restore run.
Example:
nanosim -n netlist -c cfg -cr cfgr -o output
The cfgr file contains interactive commands that you want to execute
during the restore run. The -CR option behaves the same as -cr, except
that
all the commands in the cfgr file are echoed into the .log file.
With the -cr or -CR command line option, you can have all interactive
commands in one file to be executed automatically after a restore.
This
removes the need for you to go into the interactive mode and type
commands one by one. The commands in this cfgr file are restricted to
those that can be issued during the interactive mode and other
appropriate
phases.
Please note that the configuration file used in the save run is still
valid
during the restore run. The final config commands used in the restore
run are the ones applied during the save run PLUS the ones during the
restore
run, either by using the -cr or -CR command line option or in the
interactive mode.
The most conservative command is used when "overlapping" commands
are applied. For instance, during a save run, if you have the
configuration
command search_ckt_logic el=*, and you have search_ckt_analog el=* in
the
restore run, this is just like applying two different search_ckt_xxxxx
to
the same part of circuit, the rules include both rules for these two
search_ckt_xxxxx. Since search_ckt_analog contains more rules than
search_
ckt_logic. The result is equivalent to search_ckt_analog el=*.
Reversing the order of running these two, i.e., search_ckt_analog el=*
in the save run, then search_ckt_logic el=* in the restore run, the
one
in the restore run won't have any effect because of the reason
explained
previously. Another example, having print_node_l * in a save run, then
print_node_l xi1. *, in a restore run, it makes no difference, both
output files will contain logic value changes for all nodes. But
having
print_node_l xi1.* in a save run, then print_node_l * in a restore
run, the
output file after the restore run contains all node logic value
changes
while the one from the save run only contains logic changes of xi1.*.
c. Vector files can be changed in a restore simulation
i. Stimulus values can be changed
ii. Cannot change the vector file name, rise/fall time, output
resistance.
iii. Only changes after the restore point will have effect.
d. Command line options in restore simulation
i. -t, and -i options are supported
ii. -n(format), netlist format changes are not allowed.
iii. -c , any changes to the configuration file that is used in the
save
run are ignored. When restore_ckt_state is executed, simulation
directly
jumps to the save point, EVERYTHING is restoredto the state of the
save run up
to that point.
iv. -q,-z, technology files are not changeable
v. -o, output file directory/name can be changed, however, you need to
define the save file path with the restore_ckt_state command. For
example:

restore_ckt_state ti=1u save_file=./save_dir/pw.save.1000.000000ns

Otherwise, the simulator will go to the new output directory defined
by the
nanosim command for the save file.
2.0 Limitations
2.1 Save/restore is not compatible between releases. This usage model
only
applies to version 2001.06 and beyond. In supported versions, the save
run
must be executed on the same version of the software as the restore
run
(i.e. 2001.06 save file cannot be restored with 2001.06-1).
2.2 Currently Save/Restore is not supported with BDC, HAR or VCS-ACE.
2.3 fsdb format output is not supported this time.