[Vm-dev] Dalvik vs. ART: Android virtual machines and the battle for better performance | Pocketnow

[David T. Lewis]

On Fri, Dec 13, 2013 at 01:43:03AM +0100, Nicolas Cellier wrote:
>  
> If you want to know if it's the VM, I'd say just try Cuis.
> 

+1

Not to say that VM performance isn't important, it absolutely is. So
is memory, and so it a fast CPU. But nothing beats clean design and
implementation, and Cuis is proof of that.

Dave

> 
> 2013/12/13 phil at highoctane.be <phil at highoctane.be>
> 
> >
> > Google wants to beat the speed of iOS. iOS uses native code and
> > Objective-C highly optimized dispatch loop. So, with a less powerful piece
> > of hardware, Apple devices trounce Android ones when it comes to smoothness
> > of animations, battery etc.
> >
> > As Android uses the Dalvik VM, the only way to get as speedy as iOS is to
> > go as close to native as possible.
> >
> > We are talking 60 fps for a lot of pixels these days. My Nexus 7 with
> > 4.4.2 still feels laggy compared to my iPad2. That is due to the whole
> > VM/Java thing. iPad2 is 2-core, Nexus 7 is 4-core and with a NVidia
> > graphics chip.
> >
> > AOT is working very well when it comes to Java code (well, Android Dalvik
> > bytecode here).
> > http://en.wikipedia.org/wiki/AOT_compiler
> >
> > AOT is getting a lot of traction these days. LLVM also has this.
> >
> > So, why care about 50% or 100%, the point is that it is getting faster in
> > a way that affects the user perception. Which is what matters.
> >
> > For example, Pharo feels slow compared to Dolphin, Smalltalk/X etc. Maybe
> > the VM is of equivalent speed. Not the user experience.
> >
> > Phil
> >
> > On Fri, Dec 13, 2013 at 12:13 AM, Igor Stasenko <siguctua at gmail.com>wrote:
> >
> >>
> >>
> >>
> >>
> >>  On 12 December 2013 23:57, Eliot Miranda <eliot.miranda at gmail.com>wrote:
> >>
> >>>
> >>>
> >>>
> >>>
> >>> On Thu, Dec 12, 2013 at 2:53 PM, Nicolas Cellier <
> >>> nicolas.cellier.aka.nice at gmail.com> wrote:
> >>>
> >>>>
> >>>> But he said increase in speed, not performance.
> >>>>
> >>>
> >>> Same argument.  What does it mean to complete a task 100% faster?  What
> >>> does it mean to reach your destination 100% faster?
> >>>
> >>>
> >> not much apart from the author's lack of literacy :)
> >>
> >>
> >>>
> >>>>
> >>>> 2013/12/12 Eliot Miranda <eliot.miranda at gmail.com>
> >>>>
> >>>>>
> >>>>>
> >>>>>
> >>>>>
> >>>>> On Thu, Dec 12, 2013 at 1:23 PM, Nicolas Cellier <
> >>>>> nicolas.cellier.aka.nice at gmail.com> wrote:
> >>>>>
> >>>>>>
> >>>>>> I would interpret twice as fast, and that's only 50% rather than 100%
> >>>>>> reduction of execution time :)
> >>>>>>
> >>>>>
> >>>>> relative performance = new time - old time / old time.
> >>>>> 2x = -50%
> >>>>> 3x = -75%
> >>>>> etc
> >>>>>
> >>>>> -100% means new time = 0, and performance is infinite.
> >>>>>
> >>>>>
> >>>>>>
> >>>>>>
> >>>>>> 2013/12/12 Eliot Miranda <eliot.miranda at gmail.com>
> >>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>> On Thu, Dec 12, 2013 at 1:08 PM, phil at highoctane.be <
> >>>>>>> phil at highoctane.be> wrote:
> >>>>>>>
> >>>>>>>>
> >>>>>>>>
> >>>>>>>> http://m.pocketnow.com/2013/11/13/dalvik-vs-art
> >>>>>>>>
> >>>>>>>
> >>>>>>> "The benefits? Some sources are reporting a 50% increase in speed.
> >>>>>>> Others say it?s closer to 100%. Many claim they?ve seen their battery life
> >>>>>>> increase by 25% or more!"
> >>>>>>>
> >>>>>>> Got to love those 100% speed increases.  Apps really fly when they
> >>>>>>> take no time at all...
> >>>>>>>
> >>>>>>> --
> >>>>>>> Eliot
> >>>>>>>
> >>>>>>>
> >>>>>>
> >>>>>>
> >>>>>
> >>>>>
> >>>>> --
> >>>>> best,
> >>>>> Eliot
> >>>>>
> >>>>>
> >>>>
> >>>>
> >>>
> >>>
> >>> --
> >>> best,
> >>> Eliot
> >>>
> >>>
> >>
> >>
> >> --
> >> Best regards,
> >> Igor Stasenko.
> >>
> >>
> >
> >