Re: jitter bursts
From: Girish kathalagiri <hidden>
Date: 2007-09-05 08:36:38
Unfortunately not but it did get me on the right track. The problem is caused by the e100_watchdog function. As far as I can tell e100_watchdog is called from a timer queue and therefore runs with the priority of that thread. And while I set higher priorities for softirq-net-rx and the application I missed the thread for the hardware interrupt of the network interface. So whenever a packet arived while e100_watchdog was running it got delayed. The periodic pattern is a result of this and speed difference of sender and receiver clocks. The jitter is now <50us but still with some periodic patterns. So I'll need to investigate further.
There was some discussion going on this issue on netdev .... The below link might help you. http://www.nabble.com/Re%3A-My-vote-against-eepro*-removal-t954330.html#a2532617 -- Thanks Giri