nanog mailing list archives
Re: Testing Bandwidth performance
From: "David G. Andersen" <dga () lcs mit edu>
Date: Wed, 26 Jun 2002 09:30:02 -0400
On Wed, Jun 26, 2002 at 06:18:00AM -0700, todd glassey mooed:
Oh and use something like a SNIFFER to generate the traffic. Most of what we know of as commercial computer's cannot generate more than 70% to 80% capacity on whatever network they are on because of driver overhead and OS latency etc etc etc. It was funny, but I remember testing FDDI on a UnixWARE based platform and watching the driver suck 79% of the system into the floor.
Btw, if you've got a bit of time on your hands, the Click router components have some extremely-low-overhead drivers (for specific ethernet cards under Linux). They can generate traffic at pretty impressive rates. They used them for testing DOS traffic for a while. http://pdos.lcs.mit.edu/click/ (Most of the driver overhead you see is interrupt latency; click uses an optimized polling style to really cram things through). Also, the new FreeBSD polling patches should make it so you can get more throughput from your drivers when doing tests. I understand there are similar things for Linux. -Dave -- work: dga () lcs mit edu me: dga () pobox com MIT Laboratory for Computer Science http://www.angio.net/
Current thread:
- RE: Testing Bandwidth performance, (continued)
- RE: Testing Bandwidth performance Hank Nussbacher (Jun 26)
- RE: Testing Bandwidth performance Holmes, Daniel (Jun 26)
- Testing Bandwidth performance Alan Sato (Jun 26)
- Re: Testing Bandwidth performance E.B. Dreger (Jun 26)
- Re: Testing Bandwidth performance Wojtek Zlobicki (Jun 26)
- Re: Testing Bandwidth performance Martin Hannigan (Jun 26)
- Re: Testing Bandwidth performance Valdis . Kletnieks (Jun 26)
- Re: Testing Bandwidth performance Jared Mauch (Jun 26)
- Re: Testing Bandwidth performance Martin Hannigan (Jun 26)
- Re: Testing Bandwidth performance todd glassey (Jun 26)
- Re: Testing Bandwidth performance David G. Andersen (Jun 26)
- Re: Testing Bandwidth performance todd glassey (Jun 26)