Jeff Janes <jeff(dot)janes(at)gmail(dot)com> writes:
> Do you know why that should be? I've done some work with gprof, and
> the results are pretty suspect, because the total gprof time adds up
> to only about 1/3 of the total time the backend spends on CPU
> (according to "top"), and I don't know where the unaccounted for time
> is going.
Are you sure that gprof is delivering trustworthy numbers at all?
I've seen cases where it was consistently mis-timing things.
https://bugzilla.redhat.com/show_bug.cgi?id=151763
Admittedly that was an old Linux version, but ...
regards, tom lane