Re: [PATCH v4] sched: automated per session task groups

Paul Turner
2010-12-05T05:12:06Z

On Sat, Dec 4, 2010 at 3:55 PM, James Courtier-Dutton
<james.dutton@gmail.com> wrote:
> On 3 December 2010 05:11, Paul Turner <pjt@google.com> wrote:
>>
>> I actually don't have a desktop setup handy to test "interactivity" (sad but
>> true -- working on grabbing one).  But it looks better on under synthetic
>> load.
>>
>
> What tools are actually used to test "interactivity" ?
> I posted a tool to the list some time ago, but I don't think anyone noticed.
> My tool is very simple.
> When you hold a key down, it should repeat. It should repeat at a
> constant predictable interval.
> So, my tool just waits for key presses and times when each one occurred.
> The tester simply presses a key and holds it down.
> If the time between each key press is constant, it indicates good
> "interactivity". If the time between each key press varies a lot, it
> indicates bad "interactivity".
> You can reliably test if one kernel is better than the next using
> actual measurable figures.
>
> Kind Regards
>
> James
>

Could you drop me a pointer? I can certainly give it a try. It would
be extra useful if it included any histogram functionality.

I've been using a combination of various synthetic wakeup and load
scripts and measuring the received bandwidth / wakeup latency.

They have not succeeded in reproducing the starvation or poor latency
observed by Mike above however. (Although I've pulled a box to try
reproducing his exact conditions [ e.g. user environment ] on Monday).