Re: Re: Parallel processing

Re: Re: Parallel processing

[jdh]

Re: the phrase "parallel processing":

So that beginners do not get the wrong idea I wish to make clear that Unix based systems are not designed to, and can not do parallel processing.  Strictly speaking it is also not designed to do real time processing. Unix/Linux does do multitasking by using task switching.  Unix based systems does allow users with the proper priviledge to set task priority, which helps in deciding which task gets more run time.

dh

Re: Re: Parallel processing

[Bart Schaefer]

On Sun, Mar 27, 2022 at 11:37 AM jdh <dhenman@gmail.com> wrote:
>
> So that beginners do not get the wrong idea I wish to make clear that Unix based systems are not designed to, and can not do parallel processing.

If you're going to bring this up, would you please clarify further?
The Linux kernel has supported symmetric multiprocessing since 1996.

Re: Parallel processing

[Ray Andrews]

On 2022-03-27 12:06, Bart Schaefer wrote:
> On Sun, Mar 27, 2022 at 11:37 AM jdh <dhenman@gmail.com> wrote:
>> So that beginners do not get the wrong idea I wish to make clear that Unix based systems are not designed to, and can not do parallel processing.
> If you're going to bring this up, would you please clarify further?
> The Linux kernel has supported symmetric multiprocessing since 1996.
>
Yes.  My understanding is only at the casual level, but I've taken it 
that multi-core CPUs are specifically designed to facilitate 
multiprocessing and that Linux/Unix were and are way ahead of Windows in 
taking advantage of that and have been for a whole long time.  Which is 
why M$'s own servers run Linux.

Re: Parallel processing

[Perry Smith]

> On Mar 27, 2022, at 13:37, jdh <dhenman@gmail.com> wrote:
> 
> Re: the phrase "parallel processing":
> 
> So that beginners do not get the wrong idea I wish to make clear that Unix based systems are not designed to, and can not do parallel processing.  Strictly speaking it is also not designed to do real time processing. Unix/Linux does do multitasking by using task switching.  Unix based systems does allow users with the proper priviledge to set task priority, which helps in deciding which task gets more run time.

Well… drifting off the original topic: parallel processing, real time processing, and SMP are all somewhat orthogonal concepts from each other.

The original "parallel processing" systems ran a version of AT&T unix (e.g. Sequent).  It predated SMP.  Or I suppose you could say that IBM was doing parallel processing even before that.

“Real time” processing is requirements that responses to events fall within the manufacture’s specifications.  i.e. “all context switches are guaranteed to occur within 50ms”.  Then the designers of the end applications can work with those constraints and develop systems that meet the requirements of their end users.

SMP is about the very tight coupling between the CPUs.  Apple’s latest glossy keynote on the M1 Ultra gives a whiff of the problems that parallel processing introduces which SMP solves.