On 15-10-2011 1:02, Darren New wrote:
> On 10/14/2011 12:36, andrel wrote:

>> Actually my point is that it *should not* be a user program.
>
> That's likely true. However, the frequency with which this happens
> probably doesn't warrant a kernel mechanism for a UI for picking a task
> and killing it, either. Especially since many times it happens, it's
> nothing to do with a task that's still running that you could actually
> do anything about.
>
> Indeed, it would seem what you'd really want is a way to indicate that
> if a job got to the point where it was paging too often, that would be
> enough to kill it or deprioritize its disk I/O, to the point of
> suspending it for a second or more each time some other process went
> after the disk, sort of like how Linux (seems to) does "low priority"
> disk I/O.
>
>> I know that (long, long time ago I studied OS's a bit). I obviously meant
>> the part of the kernel (and user level program in badly designed systems)
>> that handles the CAD.
>
> Oh, well, you want an entire process management system built into the
> kernel, invocable by a simple keystroke. Probably not realistic in
> modern OSes.

Taking both points together. Breaking out to a program that just lets 
you modify priorities would be enough. If that process runs at the 
highest level itself it would solve most of the problems.
That said, windows does have a priority mechanism, and the taskmanager 
is running at a high level, two levels higher than Blender and Matlab, 
so why does it not work?

>
>> I disagree, there is no other user on my machine than me*. And that is
>> also
>> why your corporate webserver is a wrong example. webservers and user
>> machines are something different. You should not mix those.
>
> If your corporate web server is thrashing, how are you going to stop it?

If it is because someone is using it for other things, like POVray, 
Blender or a game fire that person. If it is because of tasks that 
should run there fire the IT manager or the financial director, 
depending on who was responsible for buying the wrong infrastructure.

>> OS should behave different. Specifically in the area that we are
>> discussing.
>> CAD on a webserver should leave everything running (probably should
>> even be
>> disabled), but when I press CAD on my keyboard because I want control, i
>> *want control* and I know what other processes I am also stopping.
>
> Well, as the Linux enthusiasts would say, "we eagerly await your patch."
> :-)

Windows is open source now? I missed that.

> CAD should certainly not be disabled on a web server, as it does far
> more than just bring up the task manager. That's the other half of the
> problem.
>
> In pretty much every situation other than disk thrashing, CAD works
> pretty much instantly. In many cases of disk thrashing, there's nothing
> you can do about it, like my example of sync'ing gigabytes of changes to
> the disk. And modern OSes are set up to treat file reading and page
> faulting as essentially similar in many ways (and then there's memmap,
> which adds another confusion on top), so it's not really even obvious
> when there's thrashing which process is causing it or what to do about
> it, because it's entirely possible there wouldn't be thrashing if there
> weren't 3 or 4 programs all doing something at once.
>
>> *) that is at least my view of the machine. Technically it is not true.
>
> Well, that's kind of the point I'm making. :)


-- 
Apparently you can afford your own dictator for less than 10 cents per 
citizen per day.

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