Date: Fri, 14 Jan 2011 12:05:26 +0100 (CET) From: sthaug@nethelp.no To: brde@optusnet.com.au Cc: freebsd-net@FreeBSD.org Subject: Re: igb watchdog timeouts Message-ID: <20110114.120526.41705579.sthaug@nethelp.no> In-Reply-To: <20110114195049.I28551@besplex.bde.org> References: <54D25D8E-ED8C-41E8-BD14-4EB86F4D63C3@mac.com> <20110114.093936.74681829.sthaug@nethelp.no> <20110114195049.I28551@besplex.bde.org>
next in thread | previous in thread | raw e-mail | index | archive | help
> > I have a couple of servers with Broadcom (bge) GigE interfaces. These
> > servers became completely unresponsive/unusable at high network traffic
> > (presumably due to the interrupt processing) but were able to handle the
> > same traffic with no problems after switching to polling. This was in
> > the 7.0 timeframe.
> >
> > I still have the same servers/interfaces running with polling, but now
> > at 7.3.
>
> I had the opposite experience with a Broadcom 5701 (old but not low-end
> bge for PCI-X on PCI-33).
...
> OTOH, with a Broadcon 5705+ (not so old but low-end bge for PCI-33),
> interrupt moderation (host coelescing in bge-speak) is broken. It
> interrupts immediately (?) once per packet despite accepting the
> programming to interrupt once per many packets or after many microseconds.
> This results in about 1/6 of the performance of the 5701 (1/3 of the
> performance to saturate twice as many CPUs). Polling might help, but
> I tried it even less on this NIC than the other.
In my case this is Broadcom BCM5721:
bge0@pci0:4:0:0: class=0x020000 card=0x01b61028 chip=0x165914e4 rev=0x11 hdr=0x00
vendor = 'Broadcom Corporation'
device = 'NetXtreme Gigabit Ethernet PCI Express (BCM5721)'
class = network
subclass = ethernet
I have no idea whether there are known bugs in interrupt moderation for
this controller. The change in behavior when switching from interrupts
to polling was extremely noticeable.
Steinar Haug, Nethelp consulting, sthaug@nethelp.no
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20110114.120526.41705579.sthaug>