Re: [RFC/RFT] calloutng

Hi,

Can you please test with MIPS? David has a MIPS board now.

Can you also test that various performance tests haven't been
affected? Eg, do iperf tests through that MIPS board, configured up as
an AP.

Please test with a bunch of disk IO activity too.

I know this is a lot to ask for, but I'd hate to see some driver /
subsystem behaviour change because you didn't quite see the evil way
the callout mechanism is used, or how the timer stuff is affecting
driver pre-emption.

Thanks,


Adrian

On 15 December 2012 08:55, Alexander Motin <mav_at_freebsd.org> wrote:
> Hi.
>
> I'm sorry to interrupt review, but as usual good ideas came during the final
> testing, causing another round. :)  Here is updated patch for HEAD, that
> includes several new changes:
> http://people.freebsd.org/~mav/calloutng_12_15.patch
>
> The new changes are:
>  -- Precision and event aggregation code was reworked. Instead of previous
> -prec/+prec representation, precision is now single-sided -- -0/+prec. It
> allowed to significantly improve precision on long time intervals for APIs
> which imply that event should not happen before the specified time.
> Depending on CPU activity, mistake for long time intervals now will never be
> more then 1-500ms, even if specified precision allows more.
>  -- Some minor optimizations were made to reduce callout overhead and
> latency by 1.5-2us. Now on Core2Duo amd64 system with LAPIC eventtimer and
> TSC timecounter usleep(1) call from user-level executes in just 5-6us,
> instead of 7-8us before. Now it can do 180K cycles per second on single CPU
> with only partial CPU load.
>  -- Number of kernel subsystems (dcons, syscons, yarrow, led, atkbd,
> setrlimit) were modified to reduce number of interrupts, also with event
> aggregation by explicit specification of the acceptable events precision.
> Now my Core2Duo test system has only 30 interrupts per second in idle. If
> not remaining syscons events, it could easily be 15. My IvyBridge ultrabook
> first time in its history shown 5.5 hours of battery time with full screen
> brightness and 10 hours with lid closed.
>  -- Some kernel functions were added to make KPIs more complete.
>
> I've successfully tested this patch on amd64 and arm.
>
> --
> Alexander Motin
>
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