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Re: Multithreading

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On 12/22/2018 03:43 AM, Scott wrote:
> For feeding the threads, a shared job queue seems right. I made a
> simple queue with mutex locking, since it's not a big player in the
> overall process. The way it's laid out, a few thousand jobs can
> account for many minutes of run time. On the output side there's no
> contention to worry about.

Is there any i/o involved, disk accesses for example? What does the CPU 
usage look like on each of the cores? If you are on Linux gprof is easy 
to use and might give you some hints. There are commercial tools like 
TotalView that are shinier.

On Windows VS has some capability. Rational's Purify is not cheap and 
it's also painful enough that we used it very rarely.

Do the threads ever come up for air? You may need to throw sched_yield() 
in some strategic places to allow the other threads to run. Context 
switching is expensive however.

Keep the TANSTAAFL principle in mind. N cpu intensive threads on one 
core aren't going to have any magical way to get more cycles than there 
are.

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Multithreading nobody@example.org (Scott) - 2018-12-16 21:48 +0000
  Re: Multithreading Joey Pabalinas <joeypabalinas@gmail.com> - 2018-12-16 17:11 -1000
  Re: Multithreading rbowman <bowman@montana.com> - 2018-12-16 21:00 -0700
  Re: Multithreading Jorgen Grahn <grahn+nntp@snipabacken.se> - 2018-12-17 22:19 +0000
    Re: Multithreading Joey Pabalinas <joeypabalinas@gmail.com> - 2018-12-17 12:45 -1000
    Re: Multithreading nobody@example.org (Scott) - 2018-12-19 19:48 +0000
      Re: Multithreading fir <profesor.fir@gmail.com> - 2018-12-19 11:58 -0800
      Re: Multithreading Jorgen Grahn <grahn+nntp@snipabacken.se> - 2018-12-19 23:17 +0000
        Re: Multithreading "Chris M. Thomasson" <invalid_chris_thomasson@invalid.invalid> - 2018-12-19 15:31 -0800
          Re: Multithreading "Chris M. Thomasson" <invalid_chris_thomasson@invalid.invalid> - 2018-12-19 15:34 -0800
        Re: Multithreading nobody@example.org (Scott) - 2018-12-22 10:43 +0000
          Re: Multithreading fir <profesor.fir@gmail.com> - 2018-12-22 03:41 -0800
            Re: Multithreading fir <profesor.fir@gmail.com> - 2018-12-22 03:46 -0800
          Re: Multithreading Thiago Adams <thiago.adams@gmail.com> - 2018-12-22 07:14 -0800
          Re: Multithreading rbowman <bowman@montana.com> - 2018-12-22 11:41 -0700
            Re: Multithreading "Chris M. Thomasson" <invalid_chris_thomasson@invalid.invalid> - 2018-12-22 16:09 -0800
          Re: Multithreading scott@slp53.sl.home (Scott Lurndal) - 2018-12-22 19:52 +0000
            Re: Multithreading "Chris M. Thomasson" <invalid_chris_thomasson@invalid.invalid> - 2018-12-22 16:10 -0800
            Re: Multithreading nobody@example.org (Scott) - 2018-12-23 23:11 +0000
              Re: Multithreading "Chris M. Thomasson" <invalid_chris_thomasson@invalid.invalid> - 2018-12-23 15:24 -0800
                Re: Multithreading "Chris M. Thomasson" <invalid_chris_thomasson@invalid.invalid> - 2018-12-23 15:25 -0800
                Re: Multithreading fir <profesor.fir@gmail.com> - 2018-12-24 02:05 -0800
              Re: Multithreading fir <profesor.fir@gmail.com> - 2018-12-24 02:08 -0800
  Re: Multithreading fir <profesor.fir@gmail.com> - 2018-12-18 07:18 -0800
    Re: Multithreading fir <profesor.fir@gmail.com> - 2018-12-18 07:51 -0800
      Re: Multithreading fir <profesor.fir@gmail.com> - 2018-12-19 09:24 -0800
        Re: Multithreading fir <profesor.fir@gmail.com> - 2018-12-19 09:55 -0800
          Re: Multithreading fir <profesor.fir@gmail.com> - 2018-12-19 11:02 -0800
            Re: Multithreading fir <profesor.fir@gmail.com> - 2018-12-19 11:16 -0800
              Re: Multithreading fir <profesor.fir@gmail.com> - 2018-12-19 11:25 -0800
          Re: Multithreading "Chris M. Thomasson" <invalid_chris_thomasson@invalid.invalid> - 2018-12-19 15:37 -0800
            Re: Multithreading fir <profesor.fir@gmail.com> - 2018-12-19 16:03 -0800
              Re: Multithreading fir <profesor.fir@gmail.com> - 2018-12-20 08:02 -0800

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