CURRENT as gateway on not-so-fast hardware: where is a bottlneck?

Garrett Cooper yanegomi at gmail.com
Wed Aug 15 08:42:53 UTC 2012


On Wed, Aug 15, 2012 at 1:21 AM, Lev Serebryakov <lev at freebsd.org> wrote:
> Hello, Lev.
> You wrote 15 августа 2012 г., 0:45:42:
>
> LS>  Answer looks trivial: router CPU is bottleneck. But here is one additional
> LS> detail: `top' never shows less than 50% of idle when torrents are
> LS> active. And `idle' time with torrents traffic is ALWAYS is higher than
> LS> without them, but with WiFi traffic.
>   Ok,  additional  information:  it  seems,  that  `top'  is liar when
>  POLLING is enabled for em0 and vr1 NICs. I'm turned POLLING off, and
>  speeds are the same, but `idle' is no more 50%, it is `0%' when
>  gateway is overloaded.
>
>  But i still feezes under load with ULE. It looks like ULE is broken.

    Not sure what card you have, but the lem style e1000 cards were
changed recently (r238953) to use poll a bit differently. Try setting
"hw.em.use_legacy_irq=1" as a tunable and see what happens or remove
DEVICE_POLLING altogether?
    The clock and scheduling code has also been changed recently
(r239185, r239194, r239183, r239157, r239036, r239013). See if
reverting any or all of the beforementioned commits helps improve
performance for you.
HTH!
-Garrett


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