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Re: route cache DoS testing and softirqs

To: Robert.Olsson@xxxxxxxxxxx (Robert Olsson)
Subject: Re: route cache DoS testing and softirqs
From: kuznet@xxxxxxxxxxxxx
Date: Thu, 8 Apr 2004 17:29:13 +0400 (MSD)
Cc: dipankar@xxxxxxxxxx, Robert.Olsson@xxxxxxxxxxx (Robert Olsson), andrea@xxxxxxx (Andrea Arcangeli), davem@xxxxxxxxxx (David S. Miller), kuznet@xxxxxxxxxxxxx, linux-kernel@xxxxxxxxxxxxxxx, netdev@xxxxxxxxxxx, paulmck@xxxxxxxxxx, akpm@xxxxxxxx
In-reply-to: <16498.43191.733850.18276@robur.slu.se> from "Robert Olsson" at сав 06, 2004 02:55:19
Sender: netdev-bounce@xxxxxxxxxxx
Hello!

> setup. I've done a little experimental patch so *all* softirq's are run via 
> ksoftirqd. 

BTW what's about performance in this extremal situation?

Also, Robert, let's count the numbers again. With this change you should
have latency much less 100msec when priority of ksoftirqd is high.
So, rcu problem must be solved at current flow rates.
This enforces me to suspect we have another source of overflows.
F.e. one silly place could be that you set gc_min_interval via sysctl,
which uses second resolution (yup :-(). With one second you get maximal
ip_rt_max_size/1 second flow rate, it is _not_ a lot.

Alexey

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