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From: Alexander Terekhov <TEREKHOV@de.ibm.com>
To: Ross Johnson <rpj@callisto.canberra.edu.au>
Cc: Pthreads-Win32 list <pthreads-win32@sources.redhat.com>
Subject: Re: starvation in pthread_once?
Date: Tue, 08 Mar 2005 09:49:00 -0000	[thread overview]
Message-ID: <OF60172FE4.0D25A226-ONC1256FBE.00337955-C1256FBE.0035CF09@de.ibm.com> (raw)
In-Reply-To: <1110262256.6900.118.camel@desk.home>


[... pthread_once() and cancelation ...]

> Should one or more waiting threads get woken up and made to
> re-compete to run the init routine?

Yes. As for the rest, what you need here is DCSI-TLS or DCSI-MBR
(acquire/release memory barriers are needed on both Itanic and
XBOX NEXT... and, apart from hardware memory model, compiler
shall respect acquire/release semantics on IA-32 as well). For
serialization simply use a named mutex associated with address
of control variable and process id (to minimize contention).

DCSI-TLS: (__declspec(thread) for control variable; DLL issues
aside for a moment)

  if (!once_control) {
    named_mutex::guard guard(&once_control);
    if (!once_control) {
      <init>
      once_control = true;
    }
  }

DCSI-MBR: (atomic<> for control variable)

  if (!once_control.load(msync::acq)) {
    named_mutex::guard guard(&once_control);
    if (!once_control.load(msync::none)) {
      <init>
      once_control.store(true, msync::rel);
    }
  }

regards,
alexander.

  reply	other threads:[~2005-03-08  9:49 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-03-03  9:32 Gottlob Frege
2005-03-04 23:18 ` Ross Johnson
2005-03-08  2:22   ` Ross Johnson
2005-03-08  3:00     ` Gottlob Frege
2005-03-08  6:11       ` Ross Johnson
2005-03-08  9:49         ` Alexander Terekhov [this message]
2005-03-08  9:56           ` Alexander Terekhov
2005-03-08  9:58             ` Alexander Terekhov
2005-03-08 16:11               ` Gottlob Frege
2005-03-08 17:14                 ` Alexander Terekhov
2005-03-08 18:28                   ` Gottlob Frege
2005-03-14  2:47                 ` Ross Johnson
     [not found]                   ` <97ffb310503140832401faa2b@mail.gmail.com>
     [not found]                     ` <1110842168.21321.78.camel@desk.home>
     [not found]                       ` <97ffb3105031415473a3ee169@mail.gmail.com>
     [not found]                         ` <1110855601.21321.203.camel@desk.home>
     [not found]                           ` <97ffb31050321080747aa5a7c@mail.gmail.com>
     [not found]                             ` <1111464847.8363.91.camel@desk.home>
     [not found]                               ` <97ffb3105032209269b0f44e@mail.gmail.com>
2009-09-16 15:38                                 ` Gottlob Frege
2009-09-17  1:28                                   ` Ross Johnson
2005-03-08 16:05       ` Gottlob Frege

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