2009/10/16 Bateman <7thharmo...@gmail.com>:
>
> Real Time is NOT about making things "quicker". Its about reliability.
> Its about providing guarantees that certain events will happen within
> a particular time deadline no matter how the rest of the system is
> behaving. For example, lets say there is a music application
> playing..which in itself is a soft real time application as a certain
> "frame" needs to be played within a particular time deadline. Now say
> there is another application that runs a computationally intensive
> task..or for that matter a while(1) loop!. Now this while(1) could
> screw the music app. But with real-time support in place you can
> provide "reservations" to the music app which will guarantee the music
> to be played, in spite of some other application misbehaving.
>
Good point!
In current Android Kernel environment(G1/Ophone),it's really safe and
simple weak. In above case,if  other thread was blocked or busy
running, soft real time app will become abnormal.
Maybe try realtime patch will harm current weak kernel environment,
but it's really a good thing. I wish to see it. :-)


thanks
--wang xingchao

> The real-time patch in linux does provide cpu reservation budgets but
> does not provide hard guarantees what so ever.
>
> The g1 phone processor is definitely slower than new iphones. Hence by
> providing rt-extensions one will not be able to the responses of the
> applications quicker than iphone!
>
> On Oct 15, 1:10 pm, Dianne Hackborn <hack...@android.com> wrote:
>> On Wed, Oct 14, 2009 at 10:17 PM, vamsi android 
>> <vamsi.andr...@gmail.com>wrote:
>>
>> > Running the rt kernels will just slow down your android system, which is
>>
>> >  not what I think you want it to do.
>>
>> >      *--> Regarding Android system performance, at present when we compare
>> > iphone performance
>> >           and G1 performance we can clearly see the difference. So, what I
>> > was thinking was to make
>> >           android performance better and comatialble to iphone. The speed
>> > with which applications are loaded,
>> >           and accessed are not matching with iphone!!
>> > *
>>
>> Comparing what vs. what?  Are you comparing them on the same hardware?  If
>> not, this "observation" is useless, and I certainly I can't see how it
>> brings you to jump to "oh we need a real time scheduler."  (Though that
>> said, there is another non-realtime alternative scheduler that apparently
>> may provide noticeable improvement over the stock one.)
>>
>> --
>> Dianne Hackborn
>> Android framework engineer
>> hack...@android.com
>>
>> Note: please don't send private questions to me, as I don't have time to
>> provide private support, and so won't reply to such e-mails.  All such
>> questions should be posted on public forums, where I and others can see and
>> answer them.
>
> >
>

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