Re: network slowness/freez-up since update 10/11

From: Kris Kennaway <kris_at_obsecurity.org>
Date: Wed, 13 Oct 2004 16:58:16 -0700
On Thu, Oct 14, 2004 at 03:44:12AM +0400, Andrey Chernov wrote:
> On Wed, Oct 13, 2004 at 04:23:18PM -0700, Bruce M Simpson wrote:
> > On Wed, Oct 13, 2004 at 04:27:22PM -0400, Robert Watson wrote:
> > > There appears to bea problem with if_de cards and Giant-free operation.
> > > I'm working with John Baldwin to try and diagnose it.  Could you try
> > > putting debug.mpsafenet=0 in /boot/loader.conf and reboot to confirm that
> > > this is what's going on?
> > 
> > The de(4) driver is a bit of a mess as regards locking.
> > I had a look at this back in June/July but no longer have the hardware.
> > It would probably be best to bring it under IFF_NEEDSGIANT.
> 
> Even with its locking mess it works perfectly in -current until late 
> August.

You mean, until rwatson changed the default to debug.mpsafenet=1? :-)

----
rwatson     2004-08-28 15:11:13 UTC

  FreeBSD src repository

  Modified files:
    sys/conf             options
    sys/sys              kernel.h
    sys/net              netisr.c
  Log:
  Change the default disposition of debug.mpsafenet from 0 to 1, which
  will cause the network stack to operate without the Giant lock by
  default.  This change has the potential to improve performance by
  increasing parallelism and decreasing latency in network processing.

  [...]

----

debug.mpsafenet=0 is the known workaround, already mentioned in this
thread.  It hides the locking bugs by running the driver under Giant.

Kris

Received on Wed Oct 13 2004 - 21:58:17 UTC

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