[ntp:questions] NTP vs RADclock?
rick.jones2 at hp.com
Mon Jun 11 17:16:59 UTC 2012
unruh <unruh at invalid.ca> wrote:
> On 2012-06-10, Rick Jones <rick.jones2 at hp.com> wrote:
> > I'd like to see the full output of ethtool, ethtool -i and ethtool
> > -c for your interfaces if I may. Feel free to send as direct
> > email if you prefer.
> info:10.0[unruh]>ethtool -i eth0
> driver: e1000
> version: 7.3.21-k8-NAPI
> firmware-version: N/A
> bus-info: 0000:06:00.0
> info:10.0[unruh]>ethtool -c eth0
> Coalesce parameters for eth0:
> Adaptive RX: off TX: off
> stats-block-usecs: 0
> sample-interval: 0
> pkt-rate-low: 0
> pkt-rate-high: 0
> rx-usecs: 3
> rx-frames: 0
> rx-usecs-irq: 0
> rx-frames-irq: 0
Might go ahead and set rx-usecs to zero. The Intel drivers have (or
at least had) a module parameter called InterruptThrottleRate which
tries to be rather clever.
I'm not sure just at the moment how that shows-up in the ethtool
> The fact that the distribution in round trip times is almost a
> perfect square pulse (Ie, constant probability between the minimum
> 1.4us to the max .4us) suggests that may it is polling rather than
> interrupt, altough the card certainly has an interrupt
At this stage in the Linux kernel I don't believe that NAPI can be
disabled. I believe it switches over to polling only after some
threshold though. Pehaps mentioned in the previous URLs.
The glass is neither half-empty nor half-full. The glass has a leak.
The real question is "Can it be patched?"
these opinions are mine, all mine; HP might not want them anyway... :)
feel free to post, OR email to rick.jones2 in hp.com but NOT BOTH...
More information about the questions