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Groups > comp.lang.c++ > #118562
| From | "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> |
|---|---|
| Newsgroups | comp.lang.c++ |
| Subject | Re: Idea for spin-wait loops |
| Date | 2024-03-26 13:31 -0700 |
| Organization | A noiseless patient Spider |
| Message-ID | <utvbas$2anr0$7@dont-email.me> (permalink) |
| References | (4 earlier) <uttd1r$1ervd$1@dont-email.me> <utu71j$1obp8$1@raubtier-asyl.eternal-september.org> <utv9l7$2anr0$2@dont-email.me> <utvar6$2b6dl$1@raubtier-asyl.eternal-september.org> <utvb9l$2anr0$6@dont-email.me> |
On 3/26/2024 1:30 PM, Chris M. Thomasson wrote: > On 3/26/2024 1:23 PM, Bonita Montero wrote: >> Am 26.03.2024 um 21:02 schrieb Chris M. Thomasson: >>> On 3/26/2024 3:12 AM, Bonita Montero wrote: >>>> Am 26.03.2024 um 03:48 schrieb Chris M. Thomasson: >>>>> On 3/23/2024 11:38 PM, Bonita Montero wrote: >>>>>> Am 23.03.2024 um 21:58 schrieb Chris M. Thomasson: >>>>>>> On 3/23/2024 1:52 PM, Chris M. Thomasson wrote: >>>>>>>> On 3/23/2024 9:53 AM, Bonita Montero wrote: >>>>>>>>> I've got a nice idea for a new processor-extrension for spin-wait >>>>>>>>> -loops. The idea is that a thread of a processors enters a sleep >>>>>>>>> state if a word in memory is equal to a certain register until >>>>>>>>> the cacheline containing the word is modified or there's a timeout >>>>>>>>> according to the timestamp-counter's value. >>>>>>>>> This would eliminate active spinning and polling a value in >>>>>>>>> memory. >>>>>>>>> Polling would occur only if the cacheline would be modified by >>>>>>>>> another thread. >>>>>>>> >>>>>>>> futex >>>>>>> >>>>>>> MWAIT? >>>>>> >>>>>> MWAIT has no timeout. >>>>>> >>>>> >>>>> Not sure how important it would be for MWAIT to have a timeout... >>>>> You are referring to user space, right? >>>> >>>> MWAIT could be used for limited spinning like glibc's pthread_mutex >>>> is capable. The advantage of a MWAIT with timout would be much less >>>> interconnect-traffic compared to polling. >>>> >>> >>> MWAIT is meant to get around polling? >> >> MWAIT could replace polling / spinning on a mutex for a limited >> time if it would have a timeout. >> > > So, you timeout, check some other stuff, then wait again. Still sounds > like polling? Sounds like you want a hardware based futex.
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Idea for spin-wait loops Bonita Montero <Bonita.Montero@gmail.com> - 2024-03-23 17:53 +0100
Re: Idea for spin-wait loops "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-03-23 13:52 -0700
Re: Idea for spin-wait loops "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-03-23 13:58 -0700
Re: Idea for spin-wait loops Bonita Montero <Bonita.Montero@gmail.com> - 2024-03-24 07:38 +0100
Re: Idea for spin-wait loops "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-03-25 19:48 -0700
Re: Idea for spin-wait loops Bonita Montero <Bonita.Montero@gmail.com> - 2024-03-26 11:12 +0100
Re: Idea for spin-wait loops "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-03-26 13:02 -0700
Re: Idea for spin-wait loops Bonita Montero <Bonita.Montero@gmail.com> - 2024-03-26 21:23 +0100
Re: Idea for spin-wait loops "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-03-26 13:30 -0700
Re: Idea for spin-wait loops "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-03-26 13:31 -0700
Re: Idea for spin-wait loops Bonita Montero <Bonita.Montero@gmail.com> - 2024-03-27 10:18 +0100
Re: Idea for spin-wait loops Michael S <already5chosen@yahoo.com> - 2024-03-27 17:09 +0200
Re: Idea for spin-wait loops "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-03-27 12:58 -0700
Re: Idea for spin-wait loops Bonita Montero <Bonita.Montero@gmail.com> - 2024-03-24 07:37 +0100
Re: Idea for spin-wait loops "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-03-24 12:33 -0700
Re: Idea for spin-wait loops scott@slp53.sl.home (Scott Lurndal) - 2024-03-24 20:43 +0000
Re: Idea for spin-wait loops Bonita Montero <Bonita.Montero@gmail.com> - 2024-03-25 07:23 +0100
Re: Idea for spin-wait loops Michael S <already5chosen@yahoo.com> - 2024-03-25 14:34 +0200
Re: Idea for spin-wait loops Michael S <already5chosen@yahoo.com> - 2024-03-25 19:11 +0200
Re: Idea for spin-wait loops Bonita Montero <Bonita.Montero@gmail.com> - 2024-03-25 18:53 +0100
Re: Idea for spin-wait loops "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-03-26 13:13 -0700
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