kern.polling.lost_polls

Brett Glass brett at lariat.net
Fri Nov 20 21:35:25 UTC 2009


Everyone:

I've been experimenting with using device polling on a router with six Ethernet
interfaces that handles lots of traffic. I turned polling on, and set HZ=4000
to minimize latency and ensure that enough time was allocated to handle all of
the incoming packets. But the sysctl variable kernel.polling.lost_polls keeps
incrementing! The documentation of this variable isn't very good, so I am not
sure what this means. Does it mean that I should set kern.hz lower (perhaps
to 2000) and kern.polling.burst_max higher? Or that running the interfaces
in interrupt-driven mode would be more effective? How can I tell? (Feel free
to ask for more information about the hardware or kernel config if it would
help you to provide a good answer.)

--Brett Glass


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