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* [9fans] /dev/realtime doesn't exist?
@ 2023-08-29 10:46 dusan3sic
  2023-08-29 17:18 ` ori
  0 siblings, 1 reply; 4+ messages in thread
From: dusan3sic @ 2023-08-29 10:46 UTC (permalink / raw)
  To: 9fans

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I was reading an article about plan9's realtime scheduler edf (http://doc.cat-v.org/plan_9/real_time/real_time_in_a_real_operating_system/real_time_in_a_real_operating_system.pdf, page 7), and they mentioned using /dev/realtime to create realtime processes, but /dev/realtime doesn't exist on my machine (I am using 9front). I found a post here from 07 saying something about removing it a long time ago, but it got no answers. 

In proc(3) they mention some commands for configuring realtime processes but I don't know if that is to configure an already made realtime process or to make one from a regular. How do i make realtime processes in these days?
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* Re: [9fans] /dev/realtime doesn't exist?
  2023-08-29 10:46 [9fans] /dev/realtime doesn't exist? dusan3sic
@ 2023-08-29 17:18 ` ori
  2023-08-29 18:27   ` Charles Forsyth
  0 siblings, 1 reply; 4+ messages in thread
From: ori @ 2023-08-29 17:18 UTC (permalink / raw)
  To: 9fans

Quoth dusan3sic@gmail.com:
> I was reading an article about plan9's realtime scheduler edf (http://doc.cat-v.org/plan_9/real_time/real_time_in_a_real_operating_system/real_time_in_a_real_operating_system.pdf, page 7), and they mentioned using /dev/realtime to create realtime processes, but /dev/realtime doesn't exist on my machine (I am using 9front). I found a post here from 07 saying something about removing it a long time ago, but it got no answers. 
> 
> In proc(3) they mention some commands for configuring realtime processes but I don't know if that is to configure an already made realtime process or to make one from a regular. How do i make realtime processes in these days?

it's the bits you found in /proc; there are no (longer?)
any special real time processes; any process can become
real time by setting up deadlines at any point.

/dev/realtime isn't needed any more.

unfortunately, I'm not aware of any programs using it.

(that may be a good question for the list: where was the
real time scheduler used, and does any code using it
survive?)



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* Re: [9fans] /dev/realtime doesn't exist?
  2023-08-29 17:18 ` ori
@ 2023-08-29 18:27   ` Charles Forsyth
  2023-08-29 19:45     ` Skip Tavakkolian
  0 siblings, 1 reply; 4+ messages in thread
From: Charles Forsyth @ 2023-08-29 18:27 UTC (permalink / raw)
  To: 9fans

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There's another paper from an iwp9 http://9p.io/iwp9/Real-time.pdf that
might provide more detail

On Tue, 29 Aug 2023 at 18:19, <ori@eigenstate.org> wrote:

> Quoth dusan3sic@gmail.com:
> > I was reading an article about plan9's realtime scheduler edf (
> http://doc.cat-v.org/plan_9/real_time/real_time_in_a_real_operating_system/real_time_in_a_real_operating_system.pdf,
> page 7), and they mentioned using /dev/realtime to create realtime
> processes, but /dev/realtime doesn't exist on my machine (I am using
> 9front). I found a post here from 07 saying something about removing it a
> long time ago, but it got no answers.
> >
> > In proc(3) they mention some commands for configuring realtime processes
> but I don't know if that is to configure an already made realtime process
> or to make one from a regular. How do i make realtime processes in these
> days?
> 
> it's the bits you found in /proc; there are no (longer?)
> any special real time processes; any process can become
> real time by setting up deadlines at any point.
> 
> /dev/realtime isn't needed any more.
> 
> unfortunately, I'm not aware of any programs using it.
> 
> (that may be a good question for the list: where was the
> real time scheduler used, and does any code using it
> survive?)
> 

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* Re: [9fans] /dev/realtime doesn't exist?
  2023-08-29 18:27   ` Charles Forsyth
@ 2023-08-29 19:45     ` Skip Tavakkolian
  0 siblings, 0 replies; 4+ messages in thread
From: Skip Tavakkolian @ 2023-08-29 19:45 UTC (permalink / raw)
  To: 9fans

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I wrote an example 20 years ago, but couldn't get it to work. I found a
copy in this thread:

https://9fans.topicbox.com/groups/9fans/T6fea0dd928cee45d-M9987c73da1c5b3190e83c561/9fans-trace-c



On Tue, Aug 29, 2023, 11:29 AM Charles Forsyth <charles.forsyth@gmail.com>
wrote:

> There's another paper from an iwp9 http://9p.io/iwp9/Real-time.pdf that
> might provide more detail
>
> On Tue, 29 Aug 2023 at 18:19, <ori@eigenstate.org> wrote:
>
>> Quoth dusan3sic@gmail.com:
>> > I was reading an article about plan9's realtime scheduler edf (
>> http://doc.cat-v.org/plan_9/real_time/real_time_in_a_real_operating_system/real_time_in_a_real_operating_system.pdf,
>> page 7), and they mentioned using /dev/realtime to create realtime
>> processes, but /dev/realtime doesn't exist on my machine (I am using
>> 9front). I found a post here from 07 saying something about removing it a
>> long time ago, but it got no answers.
>> >
>> > In proc(3) they mention some commands for configuring realtime
>> processes but I don't know if that is to configure an already made realtime
>> process or to make one from a regular. How do i make realtime processes in
>> these days?
>> 
>> it's the bits you found in /proc; there are no (longer?)
>> any special real time processes; any process can become
>> real time by setting up deadlines at any point.
>> 
>> /dev/realtime isn't needed any more.
>> 
>> unfortunately, I'm not aware of any programs using it.
>> 
>> (that may be a good question for the list: where was the
>> real time scheduler used, and does any code using it
>> survive?)
>> 
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2023-08-29 10:46 [9fans] /dev/realtime doesn't exist? dusan3sic
2023-08-29 17:18 ` ori
2023-08-29 18:27   ` Charles Forsyth
2023-08-29 19:45     ` Skip Tavakkolian

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