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Groups > comp.programming > #3924
| From | aminer <aminer@toto.net> |
|---|---|
| Newsgroups | comp.programming.threads, comp.programming |
| Subject | Re: There is still a problem... |
| Date | 2013-10-11 19:36 -0700 |
| Organization | albasani.net |
| Message-ID | <l3a228$lvj$1@news.albasani.net> (permalink) |
| References | <l39vf3$hnr$1@news.albasani.net> <l3a1m1$ljg$1@news.albasani.net> |
Cross-posted to 2 groups.
Sorry i correct... Even if the number of threads are greater than the number of cores , this will not take too much CPU ressources, cause we are spinning and using sleep(0) for example , so it's not a big problem for waitfree FIFO queue algorithms. Thank you, Amine Moulay Ramdane. On 10/11/2013 7:30 PM, aminer wrote: > > > Hello, > > I think if the number of threads are not greater than the number > of cores , so the spin-wait for an item in the queue will not be a big > problem, it will not take too much CPU ressources in each core, so i > think waitfree algorithms are still usefull. > > > But lockfree algorithms do not minimize efficiently the cache-coherence > traffic, they generate too much cache coherence traffic and they > are not FIFO fair , so they are not starvation-free, hence i think they > are bad. > > > Thank you, > Amine Moulay Ramdane. > > > > On 10/11/2013 6:52 PM, aminer wrote: >> >> Hello, >> >> We have to be smart, i have invented a waitfree bounded FIFO queue >> and i was writing the algorithm on a paper and thinking at the same >> time, it's true that my new algorithm satisfies the FIFO fairness >> requirement, it also minimizes efficiently the cache-coherence >> traffic... but there is still a problem, this waitfree FIFO queue >> doesn't statisfies a requirement, wich one? when there is no items in >> the queue the threads must not spin-wait cause it's CPU inefficient i >> think, >> and those lockfree and waitfree algorithms must use a spin-wait >> mechanism when there is no items in the queue and they want to wait >> for items in the queue etc. and my new waitfree algorithm must also use >> a spin-wait mechanism in this case, so >> they will take too many CPU ressources if there is no items in >> the queue, so to satisfy this requirement we must use my SemaCondvar >> or a FIFO fair Semaphore , but this will slow too much the FIFO queue.. >> so as you are noticing with me it's not a silver bullet. >> >> >> Hope you have understood my ideas... >> >> >> >> Thank you, >> Amine Moulay Ramdane. >> >> >> >> >> >> >> >
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There is still a problem... aminer <aminer@toto.net> - 2013-10-11 18:52 -0700
Re: There is still a problem... aminer <aminer@toto.net> - 2013-10-11 19:30 -0700
Re: There is still a problem... aminer <aminer@toto.net> - 2013-10-11 19:36 -0700
Re: There is still a problem... aminer <aminer@toto.net> - 2013-10-11 19:46 -0700
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