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Groups > comp.programming.threads > #2243

Re: About lockfree and waitfree... (2nd try)

From nmm@needham.csi.cam.ac.uk (Nick Maclaren)
Newsgroups comp.programming.threads, comp.programming, comp.arch
Subject Re: About lockfree and waitfree... (2nd try)
Date 2014-04-24 18:02 +0100
Organization Department of Deniable Assertions
Message-ID <ljbg2r$9na$1@needham.csi.cam.ac.uk> (permalink)
References <lif821$inj$1@news.albasani.net> <lj97cc$hfk$1@dont-email.me> <lj994h$n3c$1@needham.csi.cam.ac.uk> <87y4yu654p.fsf@GraySage.COM>

Cross-posted to 3 groups.

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In article <87y4yu654p.fsf@GraySage.COM>, Chris Gray  <cg@GraySage.COM> wrote:
>
>> Yes :-)  Simply getting distinct sequences of keys with each thread's
>> sequence sequential is easy, but not very useful.  Your description
>> is correct, but incomplete, because there is also the requirement
>> for sequential consistency.  And some (many?) algorithms that want
>> numbers of that form want them consistent with memory accesses.
>
>I promised myself I wouldn't post on this group, since I'm not qualified, but
>I've been thinking about this one. I too am a software guy.

Don't worry - few of us are - indeed, I am about as unqualified in
IT (in a formal sense) as anyone, being of an era when we learnt
by being dropped in the deep end :-)

>What exactly does "sequential consistency" mean? Does it mean that successive
>reads of the TAN facility return a strict counting sequence of values? If so,
>then I certainly can't see any kind of realistic solution.

No.  It means that separate threads see sequences of numbers that
could have been produced from a single server returning monotonically
increasing values.

    http://en.wikipedia.org/wiki/Sequential_consistency


Regards,
Nick Maclaren.

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Thread

About lockfree and waitfree... aminer <aminer@toto.net> - 2014-04-13 19:54 -0700
  Re: About lockfree and waitfree... "Chris M. Thomasson" <no@spam.invalid> - 2014-04-13 19:38 -0700
    Re: About lockfree and waitfree... "Chris M. Thomasson" <no@spam.invalid> - 2014-04-13 19:47 -0700
      Re: About lockfree and waitfree... aminer <aminer@toto.net> - 2014-04-13 22:56 -0700
      Re: About lockfree and waitfree... "Chris M. Thomasson" <no@spam.invalid> - 2014-04-14 14:08 -0700
        Re: About lockfree and waitfree... "Chris M. Thomasson" <no@spam.invalid> - 2014-04-14 14:23 -0700
          Re: About lockfree and waitfree... Ivan Godard <ivan@ootbcomp.com> - 2014-04-14 16:27 -0700
          Re: About lockfree and waitfree... (2nd try) Ivan Godard <ivan@ootbcomp.com> - 2014-04-14 16:29 -0700
            Re: About lockfree and waitfree... (2nd try) "Chris M. Thomasson" <no@spam.invalid> - 2014-04-15 10:04 -0700
              Re: About lockfree and waitfree... (2nd try) Ivan Godard <ivan@ootbcomp.com> - 2014-04-15 10:34 -0700
                Re: About lockfree and waitfree... (2nd try) "Chris M. Thomasson" <no@spam.invalid> - 2014-04-17 16:35 -0700
                Re: About lockfree and waitfree... (2nd try) Ivan Godard <ivan@ootbcomp.com> - 2014-04-17 17:04 -0700
                Re: About lockfree and waitfree... (2nd try) nmm@needham.csi.cam.ac.uk (Nick Maclaren) - 2014-04-18 09:54 +0100
                Re: About lockfree and waitfree... (2nd try) Ivan Godard <ivan@ootbcomp.com> - 2014-04-18 02:31 -0700
                Re: About lockfree and waitfree... (2nd try) nmm@needham.csi.cam.ac.uk (Nick Maclaren) - 2014-04-18 11:56 +0100
                Re: About lockfree and waitfree... (2nd try) rpw3@rpw3.org (Rob Warnock) - 2014-04-18 11:26 +0000
                Re: About lockfree and waitfree... (2nd try) Ivan Godard <ivan@ootbcomp.com> - 2014-04-18 13:30 -0700
                Re: About lockfree and waitfree... (2nd try) "Chris M. Thomasson" <no@spam.invalid> - 2014-04-21 14:25 -0700
                Re: About lockfree and waitfree... (2nd try) "Chris M. Thomasson" <no@spam.invalid> - 2014-04-21 14:31 -0700
                Re: About lockfree and waitfree... (2nd try) Ivan Godard <ivan@ootbcomp.com> - 2014-04-21 14:53 -0700
                Re: About lockfree and waitfree... (2nd try) "Chris M. Thomasson" <no@spam.invalid> - 2014-04-22 14:21 -0700
                Re: About lockfree and waitfree... (2nd try) "Chris M. Thomasson" <no@spam.invalid> - 2014-04-22 14:36 -0700
                Re: About lockfree and waitfree... (2nd try) Ivan Godard <ivan@ootbcomp.com> - 2014-04-22 15:30 -0700
                Re: About lockfree and waitfree... (2nd try) "Chris M. Thomasson" <no@spam.invalid> - 2014-05-01 00:48 -0700
                Re: About lockfree and waitfree... (2nd try) "Chris M. Thomasson" <no@spam.invalid> - 2014-05-25 13:16 -0700
                Re: About lockfree and waitfree... (2nd try) "Chris M. Thomasson" <no@spam.invalid> - 2014-04-21 14:34 -0700
                Re: About lockfree and waitfree... (2nd try) Robert Wessel <robertwessel2@yahoo.com> - 2014-04-21 16:42 -0500
                Re: About lockfree and waitfree... (2nd try) Ivan Godard <ivan@ootbcomp.com> - 2014-04-21 15:02 -0700
                Re: About lockfree and waitfree... (2nd try) nmm@needham.csi.cam.ac.uk (Nick Maclaren) - 2014-04-22 09:05 +0100
                Re: About lockfree and waitfree... (2nd try) Stephen Fuld <SFuld@alumni.cmu.edu.invalid> - 2014-04-22 09:27 -0700
                Re: About lockfree and waitfree... (2nd try) Ivan Godard <ivan@ootbcomp.com> - 2014-04-22 09:45 -0700
                Re: About lockfree and waitfree... (2nd try) nmm@needham.csi.cam.ac.uk (Nick Maclaren) - 2014-04-22 18:08 +0100
                Re: About lockfree and waitfree... (2nd try) Stephen Fuld <SFuld@alumni.cmu.edu.invalid> - 2014-04-23 12:08 -0700
                Re: About lockfree and waitfree... (2nd try) nmm@needham.csi.cam.ac.uk (Nick Maclaren) - 2014-04-23 20:32 +0100
                Re: About lockfree and waitfree... (2nd try) Stephen Fuld <SFuld@alumni.cmu.edu.invalid> - 2014-04-23 13:21 -0700
                Re: About lockfree and waitfree... (2nd try) nmm@needham.csi.cam.ac.uk (Nick Maclaren) - 2014-04-23 21:51 +0100
                Re: About lockfree and waitfree... (2nd try) Chris Gray <cg@GraySage.COM> - 2014-04-24 10:53 -0600
                Re: About lockfree and waitfree... (2nd try) nmm@needham.csi.cam.ac.uk (Nick Maclaren) - 2014-04-24 18:02 +0100
                Re: About lockfree and waitfree... (2nd try) Stephen Fuld <SFuld@alumni.cmu.edu.invalid> - 2014-04-25 13:39 -0700
                Re: About lockfree and waitfree... (2nd try) "Chris M. Thomasson" <no@spam.invalid> - 2014-04-22 22:08 -0700
            Re: About lockfree and waitfree... (2nd try) George Neuner <gneuner2@comcast.net> - 2014-04-17 21:15 -0400
              Re: About lockfree and waitfree... (2nd try) George Neuner <gneuner2@comcast.net> - 2014-04-17 21:25 -0400
                Re: About lockfree and waitfree... (2nd try) Ivan Godard <ivan@ootbcomp.com> - 2014-04-17 19:17 -0700
                Re: About lockfree and waitfree... (2nd try) George Neuner <gneuner2@comcast.net> - 2014-04-18 00:46 -0400
              Re: About lockfree and waitfree... (2nd try) Ivan Godard <ivan@ootbcomp.com> - 2014-04-17 18:52 -0700
    Re: About lockfree and waitfree... aminer <aminer@toto.net> - 2014-04-13 22:54 -0700

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