Periodical interrupt storm when playing game with USB keyboard

[blubee blubeeme]

On Tue, Jan 23, 2018 at 9:48 AM, Adrian Chadd <adrian.chadd at gmail.com>
wrote:

> Hi
>
> Yeah the timers eventually get coalesced unless someone's asking for a
> ridciulously accurate timer value.
>
> So is some driver asking for hyper-accurate callout timer that isn't
> being coalesced? hps, is there any useful debugging to try and find
> callouts that are requesting stupidly accurate timers? Maybe a dtrace
> probe on the callout schedule entry point?
>
>
>
> -adrian
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I'd say dtrace might be able to get you in the right direction very quickly.

I used SDL in the past for android apps and the code is very Linux
specific. I am sure there's some Linux related timers in there somewhere
that FreeBSD is returning nothing from and that's what's killing the
performance.

I can almost guarantee that none of the SDL designers and or programmers
use any *BSD systems.

The easiest solution would be to go look at the timer code and implement
something that FreeBSD can work with and try to get that upstream.

These are just a few of the issues that will crop up when devs try to just
use shims to hook into the Linux kernel. Do the design work up front and
implement things in a native way or enjoy the jank.

DTrace should be able to point you in the right direction relatively
quickly.
The DTraceBook:
https://www.amazon.com/DTrace-Dynamic-Tracing-Solaris-FreeBSD/dp/0132091518

Best