tuning for high connection rates

Adrian Chadd adrian at freebsd.org
Tue Dec 4 18:57:47 PST 2007

On 05/12/2007, Philipp Wuensche <cryx-freebsd at h3q.com> wrote:

> As I understand it, and correct me if I'm wrong, polling helps against
> high interrupt rates but for that intel gigabit cards have interrupt
> moderation. We don't have a problem with interrupts (20% CPU) at the
> moment but with system (100% CPU) as you can see in the system
> monitoring graphs. Interrupts sometimes peak at, but usually are under,
> the 2k interrupts/sec limit.

Begin by reading up on the hardware profiling support (hwpmc, pmc,
etc) and see if you can get some system and process-specific profiling

Kernel/System profiling will probably show you an interesting thing or
two. One thing I noticed was high in my high-TCP-transaction tests
(but not on hardware anywhere near as nice as yours!) was crypto calls
for, IIRC, syncookies.


Adrian Chadd - adrian at freebsd.org

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