Re: gettimeofday is at the end of its usefulness?

A recent question from Tim Kane prompted me to measure the overhead
costs of EXPLAIN ANALYZE, which I'd not checked in awhile.  Things
are far worse than I thought.  On my current server (by no means
lavish hardware: Xeon E5-2609 @2.40GHz) a simple seqscan can run
at something like 110 nsec per row:

regression=# create table foo as select x as f1 from generate_series(1,1000000) x;
SELECT 1000000
regression=# vacuum foo;
VACUUM
regression=# explain analyze select * from foo;
                                                  QUERY PLAN
---------------------------------------------------------------------------------------------------------------
 Seq Scan on foo  (cost=0.00..14425.00 rows=1000000 width=4) (actual time=0.053..111.720 rows=1000000 loops=1)
 Planning time: 0.222 ms
 Execution time: 166.682 ms
(3 rows)

(and, btw, this is a debug build --- without assert and memory
context checks it'd be faster.)

The problem with this number is that a simple test program shows that
gettimeofday() requires about 40 nsec on this hardware.  That means
that two-thirds of the above timing measurement is overhead.