From: James Marshall <jcmarsh@gwmail.gwu.edu>
To: musl@lists.openwall.com
Subject: Re: sched_* implemented?
Date: Tue, 1 Mar 2016 00:50:59 -0500 [thread overview]
Message-ID: <CACSoc7iNXHbPpqhh5Sfcsjqx7xcyKmWJRyXFH2KRwP1ssP-q5g@mail.gmail.com> (raw)
In-Reply-To: <20160301045920.GJ9349@brightrain.aerifal.cx>
[-- Attachment #1: Type: text/plain, Size: 1306 bytes --]
That works! Thank you for the help.
The way glibc / sched_setscheduler are setup is very... interesting.
James
On Mon, Feb 29, 2016 at 11:59 PM, Rich Felker <dalias@libc.org> wrote:
> On Mon, Feb 29, 2016 at 11:32:34PM -0500, James Marshall wrote:
> > Hi,
> >
> > I'm working on a realtime application and am trying to use musl. I would
> > like to call sched_setscheduler, but it looks like this is just a stub in
> > musl.
> >
> > However,
> >
> http://nsz.repo.hu/git/?p=musl-tables;a=blob_plain;f=tab_posix.html;hb=HEAD
> > has it marked as implemented. Am I missing something? Is there a patch
> > available?
> >
> > If there is not, any idea of how difficult it would be for me to add it
> in?
> > Or would I be better off using syscall directly instead?
> >
> > Your help and time is appreciated.
>
> The reason it doesn't do anything is that Linux does not provide a way
> to set scheduling parameters for a _process_, only for threads. The
> sched_setscheduler syscall is documented as taking a pid but actually
> takes a thread id and only operates on that thread. glibc just ignores
> this and provides sched_* functions that do the wrong thing.
>
> Fortunately there's an easy fix: use pthread_setschedparam, and
> pthread_self to get the pthread_t value you need to pass to it.
>
> Rich
>
[-- Attachment #2: Type: text/html, Size: 1981 bytes --]
prev parent reply other threads:[~2016-03-01 5:50 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-01 4:32 James Marshall
2016-03-01 4:59 ` Rich Felker
2016-03-01 5:50 ` James Marshall [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=CACSoc7iNXHbPpqhh5Sfcsjqx7xcyKmWJRyXFH2KRwP1ssP-q5g@mail.gmail.com \
--to=jcmarsh@gwmail.gwu.edu \
--cc=musl@lists.openwall.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
Code repositories for project(s) associated with this public inbox
https://git.vuxu.org/mirror/musl/
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).