Skip site navigation (1)Skip section navigation (2)
Date:      Mon, 31 Jan 2005 22:47:05 -0800 (PST)
From:      Chris Landauer <cal@rush.aero.org>
To:        ambrisko@ambrisko.com, truckman@freebsd.org
Cc:        cal@rush.aero.org
Subject:   Re: bug in calcru() - the clock is ticking
Message-ID:  <200502010647.j116l59R095780@calamari.aero.org>

next in thread | raw e-mail | index | archive | help

hihi, all -

i am currently running the experiment with both suggestions - doug's one of
simply re-ordering the equations, and my more complicated one with the
conditional (and the re-ordering) - the first significant data point will come
tomorrow, when the test cpu times pass the first error threshold of the
current set of equations

i will report the experimental results as i get them - a full description of
the analysis and experimental activities can be found on the web (and will be
updated as i get more results, generally every day or two, until the two
programs diverge in behavior, or i get tired of it)

http://www.cs.umd.edu/~cal/math/overflow-analysis.txt

it seems quite clear to me that just re-ordering the equations (part of doug's
original suggestion) would be a very good interim fix - it would clearly not
change any of the timing or values computed for short programs, and would only
affect programs that are high-usage for long times, making user programs fail
later, and system programs fail sooner (if there are any)

i asked before (does anybody know the answer?) - are there long running, high
utilization programs that are mostly system time? or mostly interrrupt time?
if not, then i recommend the re-ordering fix until the results of the analysis
and the experiments are in

more soon,
cal

Chris Landauer
Aerospace Integration Science Center
The Aerospace Corporation
cal@aero.org



Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?200502010647.j116l59R095780>