Input latency

[Thomas Voß]

On Mon, Dec 16, 2013 at 7:30 AM, Daniel van Vugt
<daniel.van.vugt at canonical.com> wrote:
> Yes indeed. I did think about that, but if you look at the merge proposal
> it's all about using the existing reports unmodified right now. And my
> primary task was to assess the feasibility of nesting vs non-nested.
>
> I wasn't going to spend any more time on input latency measurements this
> week but perhaps there is sufficient interest to get more details...
>
>

Out of curiosity: When you say leveraging existing reports, does that
mean this evaluation is using the lttng traces?

Thanks,

  Thomas

>
> On 16/12/13 14:27, Andreas Pokorny wrote:
>>
>> Hi,
>> Can we split the times up? .. decoding from evdev until a EV_SYN ..
>> internal processing in the shell.. transfer to client?
>>
>>
>>
>> On Mon, Dec 16, 2013 at 6:52 AM, Daniel van Vugt
>> <daniel.van.vugt at canonical.com <mailto:daniel.van.vugt at canonical.com>>
>>
>> wrote:
>>
>>     If I had a theory, I could test if it correlates with the spikes. At
>>     the moment I don't even have a theory.
>>
>>     The other weird thing I didn't mention was that the "lowlatency"
>>     kernel has higher latency :). But it was worth a try. As are
>>     different kernel schedulers, I haven't tried playing with them yet.
>>
>>
>>
>>     On 13/12/13 18:27, Christopher James Halse Rogers wrote:
>>
>>         On Fri, 2013-12-13 at 17:31 +0800, Daniel van Vugt wrote:
>>
>>             Here are some fun numbers I've collected about the latency
>>             between input
>>             events sent from the top-level Mir server to a client. All in
>>             milliseconds...
>>
>>             Desktop (3.12.0-7-generic)
>>             Direct 0.8ms
>>             Nested 1.3ms
>>
>>             Desktop (3.11.0-11-lowlatency)
>>             Direct 1.0ms
>>             Nested 1.7ms
>>
>>             Nexus4 (3.4.0-3-mako)
>>             Direct 0.9ms
>>             Nested 1.5ms with high variance; frequent spikes to 73ms.
>>             Sometimes 700ms.
>>
>>
>>         Do we have any way to get insight into the spikes? Something
>>         strange is
>>         obviously happening when the variance is ~3 orders of magnitude.
>>
>>
>>
>>
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