Re: Avoid stack frame setup in performance critical routines using tail calls

Hi,

David and I were chatting about this patch, in the context of his bump
allocator patch.  Attached is a rebased version that is also split up into two
steps, and a bit more polished.

I wasn't sure what a good test was. I ended up measuring
  COPY pgbench_accounts TO '/dev/null' WITH (FORMAT 'binary');
of a scale 1 database with pgbench:

c=1;pgbench -q -i -s1 && pgbench  -n -c$c -j$c -t100 -f <(echo "COPY pgbench_accounts TO '/dev/null' WITH (FORMAT 'binary');")

	average latency
HEAD:   33.865 ms
01:     32.820 ms
02:     29.934 ms

The server was pinned to the one core, turbo mode disabled.  That's a pretty
nice win, I'd say.  And I don't think this is actually the most allocator
bound workload, I just tried something fairly random...


Greetings,

Andres Freund