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From: Rob Snow <rsnow@txdirect.net>
Newsgroups: comp.unix.bsd.freebsd.misc
Subject: Re: "An HTTP software server can pummel a CPU..."
Date: 15 Sep 1995 02:31:08 GMT
Organization: G3 Research, Inc.
Lines: 63
Message-ID: <43aohc$89j@nimitz.fibr.net>
References: <gary-1309951409030001@bhb17.acadia.net> <438u8f$cok@kadath.zeitgeist.net> <439qed$rdm@lace.Colorado.EDU>
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apuzzo@snake.colorado.edu (Tony Apuzzo) wrote:
>In article <438u8f$cok@kadath.zeitgeist.net>,
>Amancio Hasty, Jr. <hasty@rah.star-gate.com> wrote:
>>gary@first.acadia.net (Gary Robinson) wrote:
>>>Hello,
>>>
>>>From an InfoWorld 6/19/95 article:
>>>
>>>"An HTTP software server can pummel a CPU, because there's no mechanism in
>>>any existing server to control the amount of processor time allotted. Ten
>>>users doing SQL questies, for instance, might bring the system to a
>>>standstill while users trying to receive static pages wait."
>>
>>Yeap , this is very true for OSes which don't have priority pre-empted
>>scheduling. For instance, right now I am running a simple program which
>>has a tight loop just chewing up the cpu while I am typing this.
>>Wait let me start five more copies...
>>So much for InfoWorld.
>>
>>Curious which OS was the article referring to ?
>>
>> Tnks,
>> Amancio
>
>You're missing the point Try this instead:
>
> sh$ for i in 1 2 3 4 5 6 7 8 9 0
> > do
> > find / -type f -exec grep slow '{}' \; 2>&1 >/dev/null &
> > sleep 5
> > done
>
>This is a more realistic (though still pretty poor) simulation of 10 users
>doing complex SQL queries.
>
>This type of thing can only happen if your HTTP server is serving pages
>that support search engines. If you have other users trying to get regular
>pages (html code, .gif's, etc.) they will be *significantly* delayed while
>this is going on. It is possible to avoid problems like this through load
>balancing, or running the SQL on another machine, etc. I think Infoworld's
>point was that it is easy to slow an otherwise capable HTTP server to a
>crawl if you aren't careful.
>
>-Tony
>--
>*
>* Be a non-conformist like me and don't use a .sig at all.
>*
Maybe I dont quite understand this, but how about starting your SQL
queries with a high nice level?
ie. In the above example:
nice +15 find...etc...
My machine is almost always running a couple of processes doing time series
analysis and I just run them nice +15 - +20.
______________________________________________________________________
Rob Snow Powered by FreeBSD
rsnow@txdirect.net http://www.freebsd.org