On Mon, Mar 21, 2016 at 6:37 PM, Vishwas Srivastava <vishu.kernel@gmail.com> wrote:
Hi All,
            i was trying to understand the the meaning of the PR field in the "top" command.

PR field is the kernel notion of importance of a task.
It is loosely coupled with the "nice" value, which is a user-space concept.
Roughly they are related with..

PR=20+nice   (-20<= nice <=19)
which means, PR can never go below 0.

As an experiment to understand this even more, i created an user-app with real-time scheduling policy (SCHED_FIFO) and ran this application.

while the application was running i triggerred "top" and what i see that the PR value for my application displays a -ve value.
what does this mean.
If at all this is correct, what are the valid range of PR which i should expect?


Quick answer: have you check and read sched_setscheduler() in detail, especially part that explains about SCHED_FIFO?

--
regards,

Mulyadi Santosa
Freelance Linux trainer and consultant

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