Impact of track_activity_query_size on high traffic OLTP system

I have found some examples of people tweaking this
parameter track_activity_query_size to various setting such as 4000, 10000,
15000, but little discussion as to performance impact on memory usage.
What I don't have a good sense of is how significant this would be for a
high traffic system with rapid connection creation/destruction, say 1000s
per second. In such a case, would there be a reason to hesitate raising it
to 10000 from 1024? Is 10k memory insignificant? Any direction here is
much appreciated, including a good way to benchmark this kind of thing.

Thanks!