SPUG: Shared memory system

Peter Darley pdarley at kinesis-cem.com
Fri Dec 7 09:48:27 CST 2001


Jason,
	That's good advice.  I hadn't actually considered doing any benchmarking or
anything.
	In this case this is to protect the database from extra work, rather than
decreasing the amount of time it takes to present pages to the clients.  I
just hate having the database working on some huge batch job and seeing that
half of it's cycles are going toward serving repetitive largely static
stuff.
Thanks,
Peter Darley

-----Original Message-----
From: owner-spug-list at pm.org [mailto:owner-spug-list at pm.org]On Behalf Of
dancerboy
Sent: Thursday, December 06, 2001 7:39 PM
To: Colin Meyer; Peter Darley
Cc: Colin Meyer; SPUG
Subject: Re: SPUG: Shared memory system


Just a reminder: do a lot of benchmarking/profiling and testing
*before* investing a lot of effort into any performance-improving
scheme.  Very often, the bottlenecks in your code are not where you
think they are, and/or your planned optimizations won't end up
improving anything. (E.g. in most cases implementing your own disk
I/O caching is unlikely to improve performance -- and may even make
it worse -- since the OS is doing I/O caching already, and custom
Perl code is unlikely to do it any better.)

(And never, ever forget this maxim: "Premature optimization is the
root of all evil!")

-jason


At 3:49 pm -0800 12/06/2001, Colin Meyer wrote:
>On Thu, Dec 06, 2001 at 02:35:17PM -0800, Peter Darley wrote:
>>  Colin,
>>	IPC::Shareable seems to be closest to doing what I want; is
>>that included
>>  in IPC::Semaphore and it's friends? :)
>
>Yup, IPC::Shareable sits on top of IPC::Semaphore.  I do like the interface
>to IPC::Shareable, but don't try to store a "deep" Perl data structure
>with it.
>
>-C.
>
>
>
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