Preempt (Question Answered)

[leadwt]

Hi,

I've noticed that various 'preempt' packages are now available.

I am not a computer 'geek' but it seems that this preempt 'stuff' allows the kernel to handle apps. in a more efficient manner.

So my simple question is:

Are they worth loading for the ordinary 'at home' casual user like me?

Thanks

[leadwt]

Re: Preempt

Bump bump bump . . .

[abalone]

Re: Preempt

I'm not sure what packages you are talking about. Not that I'm the geek you are looking for...

[molostoff]

Re: Preempt

Hi,

I've noticed that various 'preempt' packages are now available.

I am not a computer 'geek' but it seems that this preempt 'stuff' allows the kernel to handle apps. in a more efficient manner.

So my simple question is:

Are they worth loading for the ordinary 'at home' casual user like me?

Thanks

I use linux-preempt, and it seems a bit speedy (and smooth) on my x64 kubuntu notebook.

Also I have installed all the drivers for preemptive kernel:

linux-backports-modules-alsa-lucid-preempt
linux-backports-modules-wireless-lucid-preempt

or by this cmd
sudo aptitude install `aptitude -w777 search linux[^0-9]*-preempt | awk '{print$2}'`

[abalone]

Re: Preempt

...must be 64 bit only thing...

[leadwt]

Re: Preempt

Hi,

Thanks for replies.

I've since tried out these kernels and found that the system does indeed speed-up but I'm looking to do a little more research on what they are about.

All I've seen so far is that you need a 'preempt enabled/empowered processor' and that all kernels will be 'preempt' eventually. Is this actually true and is there any down-side to using them at this time? I've not seen anything about 64 bit but that is what I am running.

[Ole Juul]

Re: Preempt

I've since tried out these kernels and found that the system does indeed speed-up but I'm looking to do a little more research on what they are about. . . .

I'm no expert, but obviously preemtive scheduling is going to be less efficient. That is, less computing is going to be done over a given amount of time. That is why servers haven't used it in the past. However, for desktop use it is more important that the computer responds to the user in a snappy manner. The background stuff isn't noticed. If you are interested in the server perspective, there is a great article by Carla Schroder here.

[molostoff]

Re: Preempt

Hi,

Thanks for replies.

I've since tried out these kernels and found that the system does indeed speed-up but I'm looking to do a little more research on what they are about.

All I've seen so far is that you need a 'preempt enabled/empowered processor' and that all kernels will be 'preempt' eventually. Is this actually true and is there any down-side to using them at this time? I've not seen anything about 64 bit but that is what I am running.

It is a definitely abstract explanation, mosty for a regular user.

Be preemptive - is a software characteristic, not hardware. Most common thing is how device drivers handle requests - if they stop kernel on the time the request is processed by the device, or gives a possibility to process other requests (to the same device or to another one). More requests can be processed simultaneously -> less timeslice quantum -> less time to responce. Indeed, preemptive kernel is more responsive.

As it seems, the backside - say some old hardware driver which will work in a nonpreemptive manner, stopping main processor for a time while handling request. It will looks like glitches and short eventual freezes usually on 'realtime' devices like mouse.

------------

As for my notebook - acer aspire with T7100 and ATI hd2300 onboard these preemptive kernels do their job fine. I have no old drivers installed, all work just outofthebox.

Except that I have found that ACPI subsystem from acer aspire is still does not conform some rules applicable to preemptive drivers. I am not deep with that, but I have just disabled use of ACPI placing 'noacpi' in a boot command line .

------------

64 or 32 bits ? 32 bit system also can be preemptive, but indeed preemptive requires more context switches between threads, and 32 can slowdown (degrade) a bit while switching between 'all these drivers', while 64 will keep switching speed in a good kind and as a result providing very short timeslice quantums - currently, as an exam, useful while processing online audio and video recording (but not for skype since it's still 32 bit software ).

[leadwt]

Re: Preempt

Hey,

Good info. thanks to both.

I've not used Skype but as it seems detrimental I'll stick to the 'organic' kernels.