| From: | Peter Eisentraut <peter_e(at)gmx(dot)net> |
|---|---|
| To: | Sean Chittenden <sean(at)chittenden(dot)org> |
| Cc: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: Optimization levels when compiling PostgreSQL... |
| Date: | 2002-09-10 23:05:03 |
| Message-ID: | Pine.LNX.4.44.0209101836430.1307-100000@localhost.localdomain |
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| Lists: | pgsql-hackers |
Sean Chittenden writes:
> Hrm, I should go check the archives, but I thought what was used was
> one step below -C[fF] and was used because of size concerns for
> embedded databases. My memory for what happens on mailing lists seems
> to be fading though so I'll look it up.
The particular decision was -CF vs. -CFa ("a" for alignment). The latter
was about 2% faster in the test case but increased the size of the
executable by 80 kB.
Note that the test case was extremely contrived -- parsing of about 70 MB
of uninteresting commands with little to no other activity. For a normal
command the scanner overhead is really small.
On the other hand, the test case was run on a x86 machine which is not
known for being sensitive to alignment. So on a different architecture
you might get more significant speedups. Try it if you like.
--
Peter Eisentraut peter_e(at)gmx(dot)net
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