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

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On 2/21/21 1:58 PM, Bonita Montero wrote:
>> 60 People come up and submit their jobs at basically the same time.
>> Each Job is going to take 1 minute of CPU time to run. Which of these
>> scheduling algorithms is 'fairer'
>> Method 1, First job in line run to completion, then the second job is
>> run to completion, then the 3rd and so on. So the first person gets his
>> results after a minute, next a minute later, and so on so the last gets
>> their results 60 minutes later.
>> Method 2, All the jobs are loaded into memory at once, and time sliced
>> between them, each getting 1 second of time, then the next, and so on.
>> Every job will finish at the end of the hour.
>> Many people will label the second method as 'fairer' as everyone gets
>> the same pain, but no one in the second example was any better off then
>> in the first, and almost everyone worse, so by most efficiency measures
>> it is clearly worse.
> 
> You can't compare that to the discussed issue because there's no
> opportunity to capture all the CPU-time by one task.

The key point isn't what resource was being managed, but how do we
really define 'fair'. The key part about the example was that many
people thought that the second method was fairer, because there was much
less difference is response times to all clients, even though it was at
the cost of making almost everyone wait longer than they needed to in
the first. The first method has an average response time of 1/2 the
second, and no one got worse performance. Only by a metric on variation
in response can the second be shown to be superior, but some think that
makes it fairer.

To define 'fairness' we need to define some metric to measure it.
Normally we can't get 'perfect' fairness except in vary special
conditions. Normally we define a system as 'fair' if every client can
get some reasonable amount of the resource (even if it isn't a 'fair
share'). Tighter definitions of 'fairness' might try to limit the
inequities in allocation (and if the clients are identical in needs, we
need ways to 'fairly' allocate needs to measure inequality). Generally,
attempts to make a system 'fairer' can often impact the efficiency of
the system. In my example, to reduce the variance in the wait times, the
average wait time doubled, and perhaps by increasing the number of
context switches we might have actually increased the total time to run
all the jobs.

My key point is that the first step is we need to define what we want to
meet as 'fair', and then we can decide if a given strategy will meet
that definition (and maybe how well).

Thus, if you want to call something 'unfair', you need to define what
you mean by fair. It is quite possible to define a RW-lock that will see
to it that as long as no locker fails to release its lock in a
reasonable time period, all requests WILL get met eventually. It just
requires that at some point after a write request gets queue, the system
stops granting new read requests (so the writer will get eventually get
in when all current readers end), and that a somewhat fair method (like
oldest) is used for granting requests when the system is free. Yes,
perhaps the simplest RW-lock will not be able to do this, but then the
issue isn't about RW-locks in general, but that style of
implementations. IF you are using some other definition of 'fair', you
need to define it.

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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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