@Deepak simulation time is related to circuit size, required precision/steps and ease of convergence. What is the size of the cirrcuit? (how many transistor approx). What is the simulation command (.tran /.dc) ? After doing the simulation, at the ngspice prompt, you can give this command:

listing logical expand > flat_list

this will create a

flat_list

file in the

~/.xschem/simulations

directory (or any other directory where your simulations are running). The '`Warning: output of command 'listing' will be truncated`' message is not an issue for our purposes. You can then get the exact number of MOS transistors in your circuit by doing in a bash shell:

grep ' m\.' flat_list | wc -l