Re: Very high bandwith packet based interface and performance problems

[Gregory Maxwell]

On Wed, Feb 21, 2001 at 02:00:55PM -0800, Nye Liu wrote:
[snip]
> This is NOT what I'm seeing at all.. the kernel load appears to be
> pegged at 100% (or very close to it), the user space app is getting
> enough cpu time to read out about 10-20Mbit, and FURTHERMORE the kernel
> appears to be ACKING ALL the traffic, which I don't understand at all
> (e.g. the transmitter is simply blasting 300MBit of tcp unrestricted)
> 
> With udp, we can get the full 300MBit throughput, but only if we shape
> the load to 300Mbit. If we increase the load past 300 MBit, the received
> frames (at the user space udp app) drops to 10-20MBit, again due to
> user-space application scheduling problems.

Perhaps excess context switches are thrashing the system?