Re: [squid-users] squid performance

actually on a switched ethernet segement between two hosts, you can get
darn close to line rate... between two hosts on our campus (different
subnets, gig in the core) I can move a file via ftp at 89Mb/s, ttcp will
push 96Mb/s over the same path.

on a shared ethernet fabric with a small number of hosts loss due to
collisions will probably limit you to maybe 60% of line rate.

that being said we're talking about performance of of a database app here
(squid) so your bottlenecks by in large are probably not in the network...

joelja

On Thu, 7 Jun 2001, Adam Lang wrote:

> You're never going to get 100 Mbps.
>
> For starters, the theoretical maximum of Ethernet is about 37% of raw wire
> speed. So even under most ideal conditions, you are never getting above
> 37Mbps on a 100 Mbps line.
>
> Next, some of that bandwidth that is not being measured but neccessary, are
> the hosts talking back and forth with each other... outside of the actual
> data being transfered.
>
> Finally, if you are plugged into a hub, you have to divided the amount of
> available bandwidth by the number of active hosts (hubs are shared
> bandwidth, sqitches aren't).
>
> If you have a 100 Mbps line, with three hosts talking on it at the same
> time, you are looking at:
>
> 100 x .37 / 3 = 11Mbps.
>
> Then you have to figure chatter between the hosts to keep a TCP session
> going... makes you realize the bandwidth still is not that amazing. :)
>
> Of course I don't have a degree in electrical engineering and the books I
> have read could be all bunk, but this is how I understand things work.
>
> Adam Lang
> Systems Engineer
> Rutgers Casualty Insurance Company
> http://www.rutgersinsurance.com
> ----- Original Message -----
> From: "Subbarao Gaddamadugu" <sgaddama@cs.uml.edu>
> To: <sgaddamadugu@hotmail.com>
> Cc: "Squid-Users" <squid-users@squid-cache.org>
> Sent: Thursday, June 07, 2001 3:42 PM
> Subject: [squid-users] squid performance
>
>
> > i'm doing a test on squid performance.
> > the client, squid and web server are connected over 100 Mbps line.
> > why can't i get more than 3.5 Mbps throughput
> >
> > how should i tune squid to use available bandwidth.
> >
> > subba
>

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Joel Jaeggli				       joelja@darkwing.uoregon.edu
Academic User Services			     consult@gladstone.uoregon.edu
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