Re: iperf takes a lot of CPU bandwidth
First Iperf is a testing tool and is not designed to be used in
conjunction with other high profile applications or in a production
environment. Second Iperf attempts to send at constant bit rate with UDP
tests. As such it can not rely on any built-in timers or sleep functions
due to inaccuracy of these functions and lack of fine granularity (<1ms).
Therefore Iperf uses busy waiting to provide as close to constant bit rate
as possible. This busy waiting consumes CPU time. Once again Iperf is a
testing tool not something to run in the background all the time.
Kevin
On Wed, 30 Apr 2003, Yaniv Kaul wrote:
> I'm running iperf 1.7.0, on Linux (RH 7.2), as a client, connected with
> IPv4 to multicast, with '-b 100K'.
> I was running another multicast application, and it seemed sluggish, so
> I looked at 'top' and saw that iperf was constantly taking loads of CPU
> bandwidth - 60% and more!
> The VNC I was connecting through was taking ~25%, the video application
> a mere ~20%. How could iperf be taking so much cpu?
>