[tpm] ftruncate (was: Fast(er) way of deleting X lines from start of a file)

[arocker at vex.net]

> Madison Kelly wrote:

> This works, but strikes me as horribly inefficient.

Beware of assumptions about performance; measure first, then decide if
optimisation is justified. What's your time worth, compared to the
system's?

If it takes ten seconds rather than 5 to do a daily job, who cares? The
same numbers for every login might be a different matter.