[haiku-bugs] Re: [Haiku] #2817: setpriority and getpriority are missing to compile ocaml out of the box under Haiku
- From: "pulkomandy" <trac@xxxxxxxxxxxx>
- Date: Fri, 16 Jan 2015 07:26:55 -0000
#2817: setpriority and getpriority are missing to compile ocaml out of the box
under Haiku
----------------------------+----------------------------
Reporter: oco | Owner: nobody
Type: enhancement | Status: new
Priority: normal | Milestone: Unscheduled
Component: System/POSIX | Version: R1/Development
Resolution: | Keywords:
Blocked By: | Blocking:
Has a Patch: 1 | Platform: All
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Comment (by pulkomandy):
What is called "team" in the BeAPI is what is called "process" in POSIX.
The setpriority documentation
(http://pubs.opengroup.org/onlinepubs/9699919799/functions/setpriority.html)
says that the priority is set for the whole process.
{{{
If the process is multi-threaded, the nice value shall affect all system
scope threads in the process.
}}}
So, the "niceness" is process global. It needs to be stored somewhere, and
getpriority can read it there and return it directly. This avoid the
rounding errors of your current implementation.
When setpriority is called, the "nice" value for the team should be
updated, and the priority for each running thread adjusted to match. When
a new thread is spawned, its priority should be adjusted according to the
current nice value.
You are right that team_info shouldn't be modified, however it is only the
user-visible information for the team (ans since getpriority already
allows getting the nice value, it doesn't need to be available in the
team_info). In headers/private/kernel/thread_types.h is the definition of
{{{struct Team}}} which is the place where the process nice value can be
stored.
Of course we need a way to get it on the kernel side, and for this
getthreadpriority and setthreadpriority must probably use a new system
call.
--
Ticket URL: <https://dev.haiku-os.org/ticket/2817#comment:18>
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