svn commit: r215368 - in stable/7/sys: arm/at91
contrib/dev/oltr dev/ae dev/an dev/ar dev/arl dev/ath dev/awi dev/ce dev/cm
dev/cnw dev/cp dev/cs dev/ctau dev/cx dev/cxgb dev/ed d...
sobomax at sippysoft.com
Wed Nov 17 13:59:26 UTC 2010
On 11/16/2010 8:12 AM, Bruce Evans wrote:
> This was quite low for yestdeay's uses (starting in about 1995), but today
> it is little missed since only yesterday's low-end hardware uses it. Most
> of today's interfaces are 1Gbps, and for this it is almost essential for
> the hardware to have a ring buffer with > 50 entries, so most of today's
> drivers ignore ifqmaxlen and set the queue length to the almost equally
> bogus value of the ring buffer size (-1). I set it to about 10000 instead
> in bge and em (10000 is too large, but fixes streaming under certain loads
> when hz is small).
One of those interfaces is if_rl, which is still quite popular these
days and supports speeds up to 1gbps (which I believe triggered this
change). But in general I agree, unfortunately FreeBSD network subsystem
is tuned for yesteday's speeds. We are seeing lot of lookups and other
issues under high PPS. I wish somebody could stand and pick up the task
of cleaning it up and re-tuning eventually for 2010. We could probably
even sponsor in part such a work (anyone).
Apart from interface tuning for Gbps speeds, another area that needs
more work is splitting up memory pool for the IPC from the memory pool
for the other networking. Today's software is highly distributed and
rock-solid IPC is a must for the FreeBSD being a solid server
application platform. That's OK when under the load we drop some
packets, but it's not OK when extreme network activity can bring down
communications between application and database system within the host
itself. And that's exactly what can happen in FreeBSD.
Sippy Software, Inc.
Internet Telephony (VoIP) Experts
MSN: sales at sippysoft.com
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