Windows 8 and audio

[wiwatti]

The first audio tests showed a high DPC latency. Now Cakewalk does a test and Winows 8 performs better than Windows 7. What happened?

I found the DPC latency was much higher in Windows 8. Cakewalk also provided figures saying that 64 bit was 20% faster than 32 bit OS for vsti. Maybe they are cooking the books? Or perhaps giving skewed impression.

64 bit OS vs 32 OS has an advantage. For example if you compile for a 64 bit OS the SSE code is faster because on a 32 bit OS, the copy of the parameters from the standards registers to the SSE registers is not as efficicent, even worst, on a 32 bit system you can have to copy a parameter to the bottom of a xmm register while it has already been put to the top...and some crazy stuffs like that

[Gonga]

If MS goal for acceptable latency for metro applications is 100ms, doesn't it also imply that we will not see audio applications in winRT tablets or winphone8?

I mean they are almost the same metro applications, arent they? Now that all three os (win8, winRT, winphone8) have the same kernel.

If this is really so I think it is very bad news as I have been hoping to see music applications also in some other platforms than iphone/ipad.


Has anybody still measured the actual latency in metro apps?




Then another question, if metro is unusable for audio and you code with normal win8 API, does it also imply that you cannot use multi touch gestures in your music app?

I'm not sure they all will use the same kernel. They will all use the Metro interface, but the RT version will run on different chips than the Pro version, so won't they have to code different kernels for Pro, RT and Phone 8?

[golemus]

I'm not sure they all will use the same kernel. They will all use the Metro interface, but the RT version will run on different chips than the Pro version, so won't they have to code different kernels for Pro, RT and Phone 8?

The kernels won't be exactly same, cannot be because of different processor architectures. But they will be very similar. The main point with the whole windows 8 scheme as I have understood is that coders can share a lot of same code and work when coding for all of the three platforms.

Even if winRT or winPhone8 would sucks as platform they will gain a lot of momentum from the fact that most of new computers will be preinstalled with win8.

[egbert]

Since WinNT there has been a HAL [hardware abstraction layer] - which sits between the kernel and the hardware and it has enabled Win NT and its successors to run on multiple hardware platforms. NT was originally develped on MIPS - believe it or not - and was ported to X86 and Alpha and PowerPC. MIPS and Alpha architectures are alive and kicking in China I believe and being built on much more up to date CMOS.

[Ashe37]

Since WinNT there has been a HAL [hardware abstraction layer] - which sits between the kernel and the hardware and it has enabled Win NT and its successors to run on multiple hardware platforms. NT was originally develped on MIPS - believe it or not - and was ported to X86 and Alpha and PowerPC. MIPS and Alpha architectures are alive and kicking in China I believe and being built on much more up to date CMOS.

The kernal doesn't work the same way as it did in the WinNT days, and the HAL isn't implemented in the same way either.

MIPS is still around, the PS2's CPU is MIPS-based.

[egbert]

The kernal doesn't work the same way as it did in the WinNT days, and the HAL isn't implemented in the same way either.

Can you say more about the differences? Was the change driven by the need for more efficiency - using hardware acceleration etc?

[Ashe37]

It was mostly to reduce latency for things like graphics drivers

[egbert]

To me the main issue with the different hardware platforms is the lack of drivers. The huge thing with Windows is the zillions of drivers that have been written and maintained for every conceivable bit of hardware you might ever want to connect to a PC. Even if the kernel can be tweaked rapidly to address new hardware as it has been done with the new platforms for WinRT (ARM etc) the existing drivers don't make it across. Much of the inertia of the Windows installed base resides in those drivers and the existing apps. Take them away and you are really trying to migrate people to a new platform (like Itanium) whether you call it WindowsX or not.