From: Kevin Grittner <Kevin.Grittner@wicourts.gov>
To: david@lang.hm
Cc: Robert Haas <robertmhaas@gmail.com>
Cc: Greg Smith <gsmith@gregsmith.com>
Cc: pgsql-performance@postgresql.org <pgsql-performance@postgresql.org>
Cc: Scott Carey <scott@richrelevance.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Jignesh K. Shah <J.K.Shah@sun.com>
Subject: Re: Proposal of tunable fix for scalability of 8.4
Date: Mon, 16 Mar 2009 10:48:32 -0500
Message-ID: <49BE2E80.EE98.0025.0@wicourts.gov> (raw)
In-Reply-To: <alpine.DEB.1.10.0903132124470.6196@asgard>
References: <alpine.GSO.2.01.0903121613270.1925@westnet.com>
<C5DED7A7.33B2%scott@richrelevance.com>
<603c8f070903121829r31cf1472ha9876e5c480a542e@mail.gmail.com>
<603c8f070903121829r31cf1472ha9876e5c480a542e@mail.gmail.com>
<12292.1236964604@sss.pgh.pa.us>
<49BA5960.EE98.0025.0@wicourts.gov>
<alpine.DEB.1.10.0903132124470.6196@asgard>
<david@lang.hm> wrote:
> On Fri, 13 Mar 2009, Kevin Grittner wrote:
>> If all data access is in RAM, why can't 80 processes
>> keep 64 threads (on 8 processors) busy? Does anybody else think
>> that's an interesting question, or am I off in left field here?
>
> I don't think that anyone is arguing that it's not intersting, but I
> also think that complete dismissal of the existing test case is also
> wrong.
Right, I just think this point in the test might give more targeted
results. When you've got many more times the number of processes than
processors, of course processes will be held up. It seems to me that
this is the point where the real issues are least likely to get lost
in the noise. It also might point out delays from the clients which
would help in interpreting the results farther down the list.
One more reason this point is an interesting one is that it is one
that gets *worse* with the suggested patch, if only by half a percent.
Without:
600: 80: Medium Throughput: 82632.000 Avg Medium Resp: 0.005
with:
600: 80: Medium Throughput: 82241.000 Avg Medium Resp: 0.005
-Kevin
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To: pgsql-performance@postgresql.org
Cc: Kevin.Grittner@wicourts.gov, david@lang.hm, robertmhaas@gmail.com, gsmith@gregsmith.com, scott@richrelevance.com, tgl@sss.pgh.pa.us, J.K.Shah@sun.com
Subject: Re: Proposal of tunable fix for scalability of 8.4
In-Reply-To: <49BE2E80.EE98.0025.0@wicourts.gov>
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