Re: [PATCH v2] chrt: Make priority optional for policies that don't use it

On Wed, Jun 18, 2025 at 10:18:29AM +0200, Benno Schulenberg wrote:
> 
> Op 17-06-2025 om 20:24 schreef Madadi Vineeth Reddy:
> > Currently, chrt requires a priority argument even for scheduling
> > policies like SCHED_OTHER and SCHED_BATCH, which ignore it.
> > 
> > This change relaxes that requirement. Now, priority is only expected
> > for SCHED_FIFO and SCHED_RR. For other policies, a default value of 0
> > is set internally and no argument is required on the command line.
> 
> Doesn't this alter the "show-the-current-policy-and-priority" behavior
> when no priority is given?  Currently `./chrt --help` says (trimmed):
 
Very good point. The priority policy (--{other,...}) should be
required to ensure that the user wants to alter the setting rather
than print the current situation. Madadi, what do you think?

>   Set policy:
>    chrt [options] --pid <priority> <pid>
> 
>   Get policy:
>    chrt [options] -p <pid>

I really don't like the use of "-p." We should use "--pid" everywhere  
(in --help, man page, and examples).

> Without the proposed change, running `chrt --other --pid $$` says:
> 
>   pid 1427's current scheduling policy: SCHED_OTHER
>   pid 1427's current scheduling priority: 0
> 
> After the change, that same command outputs nothing.  Maybe that is
> fine, but it would require some adjustment of the docs.

This is bug.

    Karel

-- 
 Karel Zak  <[email protected]>
 http://karelzak.blogspot.com