From: Greg Smith <gsmith@gregsmith.com>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Gregory Stark <stark@enterprisedb.com>
Cc: ITAGAKI Takahiro <itagaki.takahiro@oss.ntt.co.jp>
Cc: Postgres <pgsql-hackers@postgresql.org>
Subject: Re: posix_fadvise v22
Date: Fri, 2 Jan 2009 05:08:13 -0500 (EST)
Message-ID: <Pine.GSO.4.64.0901020335150.16680@westnet.com> (raw)
In-Reply-To: <603c8f070901011843p121e40afu35c4a7bdc51c051c@mail.gmail.com>
References: <FDDBA24E-FF4D-4654-BA75-692B3BA71B97@enterprisedb.com>
<8347.1229012970@sss.pgh.pa.us>
<4136ffa0812110911x4914a951o6ca502879e3dede7@mail.gmail.com>
<87k5a6tmy7.fsf@oxford.xeocode.com>
<603c8f070901011230t1afa6644racb715b975078054@mail.gmail.com>
<10658.1230843315@sss.pgh.pa.us>
<603c8f070901011843p121e40afu35c4a7bdc51c051c@mail.gmail.com>
On Thu, 1 Jan 2009, Robert Haas wrote:
> The only thing I haven't been able to do is demonstrate that this change
> actually produces a performance improvement. Either I'm testing the
> wrong thing, or it just doesn't provide any benefit on a single-spindle
> system.
When I did a round of testing on the earlier prefetch test program Greg
Stark put together, one of my single-spindle Linux system didn't show any
real benefit. So as long as you didn't see performance degrade, your not
seeing any improvement isn't bad news.
I've got a stack of hardware I can do performance testing of this patch
on, what I haven't been able to find time for is setting up any sort of
test harness right now. If you or Greg have any benchmark or test program
you could suggest that should show off the improvements here, I'd be glad
to run it on a bunch of systems and report back--I've already got a stack
of candidate ones I ran the earlier tests on to compare results against.
--
* Greg Smith gsmith@gregsmith.com http://www.gregsmith.com Baltimore, MD
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To: pgsql-hackers@postgresql.org
Cc: gsmith@gregsmith.com, robertmhaas@gmail.com, tgl@sss.pgh.pa.us, stark@enterprisedb.com, itagaki.takahiro@oss.ntt.co.jp
Subject: Re: posix_fadvise v22
In-Reply-To: <Pine.GSO.4.64.0901020335150.16680@westnet.com>
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