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Re: pthread question

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From	Geoff Clare <geoff@clare.See-My-Signature.invalid>
Subject	Re: pthread question
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Date	Wed, 11 May 2011 13:46:26 +0100
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Alexander Terekhov wrote:

>
> Geoff Clare wrote:
> [...]
>> 9. When a running thread issues the sched_yield() function, the
>>    thread becomes the tail of the thread list for its priority.
>
> That makes sense for a uniprocessor.
>
> But nowadays even pocket gadgets are multiprocessors.
>
>> POSIX doesn't standardise internals, but it does standardise how
>> threads with the above mentioned scheduling policies are scheduled.
>
> http://pubs.opengroup.org/onlinepubs/009695399/functions/xsh_chap02_09.html
>
> "For application threads with scheduling allocation domains of size
> greater than one, the rules defined for SCHED_FIFO, SCHED_RR, [TSP] and
> SCHED_SPORADIC shall be used in an implementation-defined manner."

Good point.  However, earlier in that section the standard says:

"It should be noted that the presence of multiple processors does not
automatically indicate a scheduling allocation domain size greater
than one. Conforming implementations on multi-processors may map all
or any subset of the CPUs to one or multiple scheduling allocation
domains"

> Translation: no rules whatsoever.

The way the domain-size-one rules are applied to larger domains is
"implementation-defined", which means implementations are required
to document how they are applied.  Not quite the same as "no rules
whatsoever".

-- 
Geoff Clare <netnews@gclare.org.uk>

Thread

pthread question p6 c6d6 <p6c6d6@gmail.com> - 2011-05-08 21:28 -0700
  Re: pthread question Vaclav Haisman <v.haisman@sh.cvut.cz> - 2011-05-09 07:11 +0200
  Re: pthread question Joshua Maurice <joshuamaurice@gmail.com> - 2011-05-09 11:49 -0700
    Re: pthread question David Schwartz <davids@webmaster.com> - 2011-05-09 12:24 -0700
      Re: pthread question Joshua Maurice <joshuamaurice@gmail.com> - 2011-05-09 14:22 -0700
        Re: pthread question "Chris M. Thomasson" <cristom@charter.net> - 2011-05-09 15:33 -0700
        Re: pthread question David Schwartz <davids@webmaster.com> - 2011-05-10 01:22 -0700
    Re: pthread question Geoff Clare <geoff@clare.See-My-Signature.invalid> - 2011-05-10 13:47 +0100
      Re: pthread question Alexander Terekhov <terekhov@web.de> - 2011-05-10 17:53 +0200
        Re: pthread question Geoff Clare <geoff@clare.See-My-Signature.invalid> - 2011-05-11 13:46 +0100
          Re: pthread question Alexander Terekhov <terekhov@web.de> - 2011-05-11 16:19 +0200
            Re: pthread question Geoff Clare <geoff@clare.See-My-Signature.invalid> - 2011-05-12 13:26 +0100
              Re: pthread question Alexander Terekhov <terekhov@web.de> - 2011-05-12 15:28 +0200
                Re: pthread question Geoff Clare <geoff@clare.See-My-Signature.invalid> - 2011-05-13 14:00 +0100
                Re: pthread question Alexander Terekhov <terekhov@web.de> - 2011-05-13 22:59 +0200
                Re: pthread question Geoff Clare <geoff@clare.See-My-Signature.invalid> - 2011-05-16 13:28 +0100

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