From: | Greg Smith <gsmith(at)gregsmith(dot)com> |
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To: | pgsql-hackers list <pgsql-hackers(at)postgresql(dot)org> |
Subject: | Re: EXPLAIN ANALYZE printing logical and hardware I/O per-node |
Date: | 2007-12-18 02:56:16 |
Message-ID: | Pine.GSO.4.64.0712172131190.5083@westnet.com |
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Lists: | pgsql-hackers |
On Mon, 17 Dec 2007, Decibel! wrote:
> Someone want to throw together some code that actually measures this? Maybe
> something that keeps a histogram of how many instructions take place per I/O
> request? If it turns out that counters do vary too much between CPUs, there
> might be ways that we can account for that.
I'd expect the easiest way to do a proof of concept here would be to use
the Linux oprofile tool. That's already abstracted away the differences
in hardware counters and provides a relatively simple interface to collect
the data without getting bogged down with implementation there. Starting
from scratch, going right to the hardware counters and building from
there, is a big project--they've been hacking on oprofile for almost six
years now and still aren't suggesting it's release quality yet.
--
* Greg Smith gsmith(at)gregsmith(dot)com http://www.gregsmith.com Baltimore, MD
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