[jkire]

> We have a dictionary with 3 keys 

What about larger dictionaries? With such a small one I would be worried that a significant proportion of the time would be simple overhead.

[Warning: Anecdote] When we were testing out the various JSON libraries we found simplejson much faster than json for dumps. We used large dictionaries.

Was the simplejson package using its optimized C library?

[jkire]

> In this experiment, we have stored all the dictionaries in a list and dumped the list using json.dumps()

I completely failed to read this the first time I went through. I guess this is equivalent to dumping bigger dictionaries.

> [Warning: Anecdote] When we were testing out the various JSON libraries we found simplejson much faster than json for dumps.

Turns out we were using sort_keys=True option, which apparently makes simplejson much faster than json.