Re: Inlining of couple of functions in pl_exec.c improves performance

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Amit Khandekar <amitdkhan(dot)pg(at)gmail(dot)com>
Cc: PostgreSQL Hackers <pgsql-hackers(at)lists(dot)postgresql(dot)org>
Subject: Re: Inlining of couple of functions in pl_exec.c improves performance
Date: 2020-07-05 17:21:21
Message-ID: 1301286.1593969681@sss.pgh.pa.us
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I wrote:
> I attach your original 0003 here (it still applies, with some line
> offsets). That's just so the cfbot doesn't get confused about what
> it's supposed to test now.

Pushed that part now, too.

BTW, the first test run I did on this (on x86_64) was actually several
percent *slower* than HEAD. I couldn't reproduce that after restarting
the postmaster; all later tests concurred that there was a speedup.
So I suppose that was just some phase-of-the-moon effect, perhaps caused
by an ASLR-dependent collision of bits of code in processor cache.
Still, that illustrates the difficulty of getting useful, reproducible
improvements when doing this kind of hacking. I tend to think that
most of the time we're better off leaving this to the compiler.

regards, tom lane

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