Groups > comp.programming.threads > #6330

Re: More precision about my new inventions of scalable algorithms..

From	"Chris M. Thomasson" <chris.m.thomasson.1@gmail.com>
Newsgroups	comp.programming.threads, comp.lang.c++
Subject	Re: More precision about my new inventions of scalable algorithms..
Date	2021-02-20 12:52 -0800
Organization	Aioe.org NNTP Server
Message-ID	<s0rsqq$1sm4$1@gioia.aioe.org> (permalink)
References	(2 earlier) <s0pf7d$9le$1@gioia.aioe.org> <s0pg0a$d4k$1@dont-email.me> <s0pgtc$thb$1@gioia.aioe.org> <s0qf0k$bb0$1@dont-email.me> <s0rsf4$1nos$1@gioia.aioe.org>

Cross-posted to 2 groups.

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On 2/20/2021 12:46 PM, Chris M. Thomasson wrote:
> On 2/19/2021 11:50 PM, Bonita Montero wrote:
>>> Ummm... I am not sure what you mean here. ...
>>
>> Readers can hold the mutex as long as they want.
>> And writers can do the opposite.
> 
> Indeed. But you snipped my relevant part.
> 
> 
>> So they can prevent other writers or readers to lock the mutex.
>> So RW-locks are never starvation-free.
> 
> Let me manually quote what I wrote. Its important because the type of 
> starvation your are talking about is very different than the usual meaning.
> 
> Chris M. Thomasson wrote:
> _________________________________
> [...]
> The type of starvation I am talking about is when reader activity is so 
> frequent that writers just can't seem to get in. Even if the reader 
> critical sections are short. Every time a writer wants to get in, 
> several readers jump in line. Its all about reader or writer priority, a 
> lot of rwmutex impls have that flaw. Sure a reader can hold the lock for 
> an hour, okay. Well, writers cannot get in for an hour. That's perfectly 
> normal. This is not the same type of starvation I am referring to...
> _________________________________
> 
> 
> Starvation on a rw mutex can occur when heavy reader activity actually 
> starves out writers. Some implementations can actually prioritize reads, 
> or writes. Some implementations have reader preference by design. So, 
> starvation can occur when frequent readers prevent writers from 
> acquiring write access. In other words, writers spend most of their time 
> tying and failing to acquire the mutex. This is why its important to be 
> very careful when one is implementing a rwmutex. I linked you to an 
> algorithm I invented that is loop-free. It fairly alternates between 
> batches of readers and writers. So, readers can never starve out 
> writers, even during massive reader activity, and vise versa.

Heavy writer activity starving out readers can happen, but its rather 
unusual. General use patterns for a read write mutex is when you have 
read mostly workloads.

Thread

More precision about my new inventions of scalable algorithms.. Amine Moulay Ramdane <aminer68@gmail.com> - 2021-02-18 11:07 -0800
  Re: More precision about my new inventions of scalable algorithms.. Bonita Montero <Bonita.Montero@gmail.com> - 2021-02-19 23:27 +0100
    Re: More precision about my new inventions of scalable algorithms.. "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2021-02-19 14:48 -0800
      Re: More precision about my new inventions of scalable algorithms.. Bonita Montero <Bonita.Montero@gmail.com> - 2021-02-20 00:01 +0100
        Re: More precision about my new inventions of scalable algorithms.. "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2021-02-19 15:17 -0800
          Re: More precision about my new inventions of scalable algorithms.. Bonita Montero <Bonita.Montero@gmail.com> - 2021-02-20 08:50 +0100
            Re: More precision about my new inventions of scalable algorithms.. "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2021-02-20 12:46 -0800
              Re: More precision about my new inventions of scalable algorithms.. "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2021-02-20 12:52 -0800
              Re: More precision about my new inventions of scalable algorithms.. Bonita Montero <Bonita.Montero@gmail.com> - 2021-02-21 17:16 +0100
                Re: More precision about my new inventions of scalable algorithms.. Richard Damon <Richard@Damon-Family.org> - 2021-02-21 13:15 -0500
                Re: More precision about my new inventions of scalable algorithms.. Bonita Montero <Bonita.Montero@gmail.com> - 2021-02-21 19:58 +0100
                Re: More precision about my new inventions of scalable algorithms.. Richard Damon <Richard@Damon-Family.org> - 2021-02-21 15:58 -0500
                Re: More precision about my new inventions of scalable algorithms.. "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2021-02-21 14:35 -0800
                Re: More precision about my new inventions of scalable algorithms.. Bonita Montero <Bonita.Montero@gmail.com> - 2021-02-22 06:54 +0100
                Re: More precision about my new inventions of scalable algorithms.. "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2021-02-21 22:00 -0800
                Re: More precision about my new inventions of scalable algorithms.. Bonita Montero <Bonita.Montero@gmail.com> - 2021-02-22 07:40 +0100
                Re: More precision about my new inventions of scalable algorithms.. Bonita Montero <Bonita.Montero@gmail.com> - 2021-02-22 09:20 +0100
                Re: More precision about my new inventions of scalable algorithms.. "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2021-02-22 14:54 -0800
                Re: More precision about my new inventions of scalable algorithms.. Bonita Montero <Bonita.Montero@gmail.com> - 2021-02-23 08:38 +0100
                Re: More precision about my new inventions of scalable algorithms.. "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2021-02-23 00:25 -0800
                Re: More precision about my new inventions of scalable algorithms.. Bonita Montero <Bonita.Montero@gmail.com> - 2021-02-23 20:17 +0100
                Re: More precision about my new inventions of scalable algorithms.. "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2021-02-23 11:29 -0800
                Re: More precision about my new inventions of scalable algorithms.. Bonita Montero <Bonita.Montero@gmail.com> - 2021-02-24 18:20 +0100
                Re: More precision about my new inventions of scalable algorithms.. "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2021-02-25 01:49 -0800
                Re: More precision about my new inventions of scalable algorithms.. "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2021-02-23 14:13 -0800
                Re: More precision about my new inventions of scalable algorithms.. "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2021-02-23 14:14 -0800
                Re: More precision about my new inventions of scalable algorithms.. Richard Damon <Richard@Damon-Family.org> - 2021-02-23 16:51 -0500
                Re: More precision about my new inventions of scalable algorithms.. Bonita Montero <Bonita.Montero@gmail.com> - 2021-02-24 18:22 +0100
                Re: More precision about my new inventions of scalable algorithms.. Richard Damon <Richard@Damon-Family.org> - 2021-02-24 13:28 -0500
                Re: More precision about my new inventions of scalable algorithms.. "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2021-02-24 17:16 -0800
                Re: More precision about my new inventions of scalable algorithms.. Bonita Montero <Bonita.Montero@gmail.com> - 2021-02-25 07:08 +0100
                Re: More precision about my new inventions of scalable algorithms.. "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2021-02-24 23:39 -0800
                Re: More precision about my new inventions of scalable algorithms.. Bonita Montero <Bonita.Montero@gmail.com> - 2021-02-25 09:49 +0100
                Re: More precision about my new inventions of scalable algorithms.. "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2021-02-25 01:05 -0800
                Re: More precision about my new inventions of scalable algorithms.. Bonita Montero <Bonita.Montero@gmail.com> - 2021-02-25 11:43 +0100
                Re: More precision about my new inventions of scalable algorithms.. "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2021-02-25 03:09 -0800
                Re: More precision about my new inventions of scalable algorithms.. "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2021-02-25 03:10 -0800
                Re: More precision about my new inventions of scalable algorithms.. "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2021-02-24 23:43 -0800
                Re: More precision about my new inventions of scalable algorithms.. Bonita Montero <Bonita.Montero@gmail.com> - 2021-02-22 06:52 +0100
                Re: More precision about my new inventions of scalable algorithms.. "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2021-02-21 22:10 -0800
                Re: More precision about my new inventions of scalable algorithms.. "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2021-02-21 21:47 -0800
                Re: More precision about my new inventions of scalable algorithms.. Bonita Montero <Bonita.Montero@gmail.com> - 2021-02-22 06:51 +0100
                Re: More precision about my new inventions of scalable algorithms.. "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2021-02-21 22:01 -0800
        Re: More precision about my new inventions of scalable algorithms.. "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2021-02-19 15:32 -0800
          Re: More precision about my new inventions of scalable algorithms.. "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2021-02-19 15:37 -0800
      Re: More precision about my new inventions of scalable algorithms.. Amine Moulay Ramdane <aminer68@gmail.com> - 2021-02-19 15:14 -0800

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