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Re: A thread-queue

From "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com>
Newsgroups comp.lang.c++
Subject Re: A thread-queue
Date 2022-05-27 18:24 -0700
Organization A noiseless patient Spider
Message-ID <t6rtla$3hc$1@dont-email.me> (permalink)
References (4 earlier) <t6po8o$h1t$1@dont-email.me> <t6q5sv$3q2$1@dont-email.me> <t6qg25$8j6$1@dont-email.me> <t6rf6l$em1$1@dont-email.me> <ULbkK.29059$IgSc.7575@fx45.iad>

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On 5/27/2022 2:53 PM, Scott Lurndal wrote:
> "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> writes:
>> On 5/27/2022 5:26 AM, Bonita Montero wrote:
>>> On one side the situation Chis and others are afraid of doesn't
>>> actually happen. On the other side _copying_ the contents of a
>>> thread queue without consuming them isn't a requirement to a
>>> thread queue. So I removed the copy-constructor and left the
>>> move constructor which does everthing that's needed.
>>
>> Okay. However, it still makes me a bit nervous when I see code acquiring
>> more than one lock at a time. I have had some horror shows trying to
>> debug code written by others... One of the authors said, no need to
>> worry because the locks are recursive (yuck) without a care in the world
>> about lock ordering... Argh!
> 
> Back in the early 1980s we were updating the architecture
> of the Burroughs B3500/B4700/B4900 to support SMP and a larger
> physical memory space.   One of the features added to support
> SMP was hardware instructions providing capabilities similar to mutexes and posix
> condition variables.
> 
> To prevent deadlock, every lock has a 'canonical lock number' (CLN) that
> ranges from 1 to 9999.  The hardware will not allow the LOCK
> instruction to complete successfully if there has already
> been a lock acquired with a equal or higher CLN; the instruction
> will fault instead.   Likewise the UNLK instruction would fault
> of the lock was equal to the highest CLN stored in the hardware
> task data structure.
[...]

For some reason this makes me think of my pointer hash to mutex index 
thing I did a while back. It works quite well when the resulting array 
of indices is sorted and duplicates are removed. Locking order is solid 
and removing duplicates gets around using recursive locks.

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Thread

A thread-queue Bonita Montero <Bonita.Montero@gmail.com> - 2022-05-24 04:07 +0200
  Re: A thread-queue "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2022-05-25 13:58 -0700
    Re: A thread-queue Bo Persson <bo@bo-persson.se> - 2022-05-26 01:04 +0200
      Re: A thread-queue "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2022-05-25 20:58 -0700
      Re: A thread-queue Bonita Montero <Bonita.Montero@gmail.com> - 2022-05-26 16:20 +0200
        Re: A thread-queue "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2022-05-26 22:40 -0700
          Re: A thread-queue Bonita Montero <Bonita.Montero@gmail.com> - 2022-05-27 11:33 +0200
            Re: A thread-queue Bonita Montero <Bonita.Montero@gmail.com> - 2022-05-27 14:26 +0200
              Re: A thread-queue "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2022-05-27 14:18 -0700
                Re: A thread-queue scott@slp53.sl.home (Scott Lurndal) - 2022-05-27 21:53 +0000
                Re: A thread-queue "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2022-05-27 15:43 -0700
                Re: A thread-queue scott@slp53.sl.home (Scott Lurndal) - 2022-05-28 14:51 +0000
                Re: A thread-queue "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2022-05-27 18:24 -0700
                Re: A thread-queue "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2022-05-27 18:26 -0700
                Re: A thread-queue scott@slp53.sl.home (Scott Lurndal) - 2022-05-28 14:56 +0000
                Re: A thread-queue "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2022-05-28 16:49 -0700
                Re: A thread-queue red floyd <no.spam.here@its.invalid> - 2022-05-28 17:16 -0700
                Re: A thread-queue "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2022-05-30 16:00 -0700
                Re: A thread-queue Bonita Montero <Bonita.Montero@gmail.com> - 2022-05-28 07:16 +0200
    Re: A thread-queue Bonita Montero <Bonita.Montero@gmail.com> - 2022-05-26 16:15 +0200

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