Groups > comp.lang.c++ > #119989

Re: Futexes ain't fast

From	"Chris M. Thomasson" <chris.m.thomasson.1@gmail.com>
Newsgroups	comp.lang.c++
Subject	Re: Futexes ain't fast
Date	2024-09-02 11:56 -0700
Organization	A noiseless patient Spider
Message-ID	<vb51oo$2v0pc$3@dont-email.me> (permalink)
References	<van414$3fe9t$1@raubtier-asyl.eternal-september.org> <vashj8$gpjk$1@dont-email.me> <vat7ft$k5je$7@dont-email.me> <vatohm$mu0b$1@dont-email.me>

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On 8/30/2024 5:36 PM, jseigh wrote:
> On 8/30/24 15:45, Chris M. Thomasson wrote:
>> On 8/30/2024 6:31 AM, jseigh wrote:
> ...
>>>
>>> They don't have to be fast, they just have to allow correct 
>>> synchronization
>>> and allow performant fast paths.  Can the api be improved for the 
>>> latter?
>>> Certainly yes.  It is an awkward api to use.
>>
>> 100% agreed. Eventcounts are in the mix as well.
>>
> 
> You might take a look at folly's eventcount.  It (I think) only calls
> futex wake if there are waiters, and only calls futex_wait if the
> eventcount hasn't been incremented.  I did my own C version since I'm
> working in C for now.

I need to look at it. Have been really busy lately. I think you said 
that eventcounts can be a little "too" lock-free? ;^)

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Futexes ain't fast Bonita Montero <Bonita.Montero@gmail.com> - 2024-08-28 14:09 +0200
  Re: Futexes ain't fast Bonita Montero <Bonita.Montero@gmail.com> - 2024-08-28 14:14 +0200
  Re: Futexes ain't fast "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-08-28 11:52 -0700
    Re: Futexes ain't fast Bonita Montero <Bonita.Montero@gmail.com> - 2024-08-29 05:51 +0200
      Re: Futexes ain't fast "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-08-28 21:17 -0700
        Re: Futexes ain't fast "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-08-28 21:18 -0700
          Re: Futexes ain't fast Bonita Montero <Bonita.Montero@gmail.com> - 2024-08-29 13:03 +0200
            Re: Futexes ain't fast Bonita Montero <Bonita.Montero@gmail.com> - 2024-08-29 14:33 +0200
              Re: Futexes ain't fast Bonita Montero <Bonita.Montero@gmail.com> - 2024-08-29 16:30 +0200
                Re: Futexes ain't fast "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-08-29 12:20 -0700
                Re: Futexes ain't fast Bonita Montero <Bonita.Montero@gmail.com> - 2024-08-29 21:44 +0200
                Re: Futexes ain't fast "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-08-30 15:20 -0700
                Re: Futexes ain't fast "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-09-19 13:50 -0700
                Re: Futexes ain't fast "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-08-29 13:12 -0700
                Re: Futexes ain't fast Bonita Montero <Bonita.Montero@gmail.com> - 2024-08-30 18:47 +0200
                Re: Futexes ain't fast "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-08-30 12:43 -0700
                Re: Futexes ain't fast "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-08-29 13:14 -0700
            Re: Futexes ain't fast "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-08-29 12:25 -0700
              Re: Futexes ain't fast "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-08-29 12:27 -0700
                Re: Futexes ain't fast Bonita Montero <Bonita.Montero@gmail.com> - 2024-08-29 21:45 +0200
                Re: Futexes ain't fast "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-08-30 15:35 -0700
        Re: Futexes ain't fast "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-08-28 21:20 -0700
  Re: Futexes ain't fast jseigh <jseigh_es00@xemaps.com> - 2024-08-30 09:31 -0400
    Re: Futexes ain't fast Bonita Montero <Bonita.Montero@gmail.com> - 2024-08-30 17:41 +0200
      Re: Futexes ain't fast "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-08-30 12:43 -0700
        Re: Futexes ain't fast Bonita Montero <Bonita.Montero@gmail.com> - 2024-08-30 22:03 +0200
          Re: Futexes ain't fast "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-08-30 13:04 -0700
            Re: Futexes ain't fast Bonita Montero <Bonita.Montero@gmail.com> - 2024-09-26 18:30 +0200
              Re: Futexes ain't fast "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-09-26 10:40 -0700
                Re: Futexes ain't fast Bonita Montero <Bonita.Montero@gmail.com> - 2024-09-26 19:44 +0200
                Re: Futexes ain't fast "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-09-26 10:48 -0700
                Re: Futexes ain't fast Bonita Montero <Bonita.Montero@gmail.com> - 2024-09-26 19:54 +0200
                Re: Futexes ain't fast "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-09-26 11:09 -0700
          Re: Futexes ain't fast "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-08-30 15:22 -0700
    Re: Futexes ain't fast "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-08-30 12:45 -0700
      Re: Futexes ain't fast jseigh <jseigh_es00@xemaps.com> - 2024-08-30 20:36 -0400
        Re: Futexes ain't fast "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-09-02 11:56 -0700
        Re: Futexes ain't fast "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-09-14 17:24 -0700

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