Re: Longstanding networking / SMP issue? (duplextest)

From: Bill Davidsen (davidsen@tmr.com)
Date: Fri Feb 21 2003 - 10:15:49 EST


On Thu, 20 Feb 2003, Andi Kleen wrote:

> On Thu, Feb 20, 2003 at 01:20:43AM -0800, Simon Kirby wrote:
> > On Thu, Feb 20, 2003 at 08:52:46AM +0100, Andi Kleen wrote:
> >
> > > That's probably because of the lazy ICMP socket locking used for the
> > > ICMP socket. When an ICMP is already in process the next ICMP triggered
> > > from a softirq (e.g. ECHO-REQUEST) is dropped
> > > (see net/ipv4/icmp_xmit_lock_bh())
> >
> > Hmm...and this is considered desired behavior? It seems like an odd way
> > of handling packets intended to test latency and reliability. :)
>
> IP is best-effort. Dropping packets in odd cases to make locking simpler
> is not unreasonable. Would you prefer an slower kernel?

  Software is not a zero sum exercise. Therefore "fast" and "correct" are
not mutually exclusive.

-- 
bill davidsen <davidsen@tmr.com>
  CTO, TMR Associates, Inc
Doing interesting things with little computers since 1979.

- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/



This archive was generated by hypermail 2b29 : Sun Feb 23 2003 - 22:00:33 EST