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Groups > comp.programming > #3906
| From | aminer <aminer@toto.net> |
|---|---|
| Newsgroups | comp.programming.threads, comp.programming |
| Subject | Re: About Amdahl's law 1 ... |
| Date | 2013-10-10 14:45 -0700 |
| Organization | albasani.net |
| Message-ID | <52571FFB.6070606@toto.net> (permalink) |
| References | <l36mub$7to$1@news.albasani.net> <0.c17b192606e82c58f6a0.20131010191426BST.87vc150z99.fsf@bsb.me.uk> |
Cross-posted to 2 groups.
On 10/10/2013 11:14 AM, Ben Bacarisse wrote: >> You can not use the Amdahl's to predict the exact scalability, >> >i think , and i have explained it to you that the Amdahl's laws >> >in parallel computing gives you the scalability in the worst case >> >contention scenario > No, it's a best-case formula giving the optimal speed-up if nothing gets > in the way (such as contention). You have not understood my ideas Mr. Ben Bacarisse, if you have the percentage of the serial part and percentage of the parallel part and you plug those datas into the Amdahl's law you will get the optimal/maximum speed-up, but i have noticed that you have not understood my ideas, the question is how to obtain the time inside the serial part and the time inside the parallel part? what i have tried to explain to you is that the purpose of the Amdahl's law is to predict to worst case scalability, and to do this prediction, you have just to find the maximum bound of the time inside the critical sections and the maximum of the time inside the parallel part and do your calculations to predict the worst case scalability, and of course you have to avoid the context switches by using the same number of threads than the number of cores and you have to lower cache-coherence traffic by using scalable Locks. Please reread what i have wrote and you will understand what i mean. Thank you, Amine Moulay Ramdane.
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About Amdahl's law 1 ... aminer <aminer@toto.net> - 2013-10-10 13:08 -0700
Re: About Amdahl's law 1 ... aminer <aminer@toto.net> - 2013-10-10 13:57 -0700
Re: About Amdahl's law 1 ... Ben Bacarisse <ben.usenet@bsb.me.uk> - 2013-10-10 19:14 +0100
Re: About Amdahl's law 1 ... aminer <aminer@toto.net> - 2013-10-10 14:45 -0700
Re: About Amdahl's law 1 ... Ben Bacarisse <ben.usenet@bsb.me.uk> - 2013-10-10 20:56 +0100
Re: About Amdahl's law 1 ... aminer <aminer@toto.net> - 2013-10-10 14:30 -0700
Re: About Amdahl's law 1 ... Robert Wessel <robertwessel2@yahoo.com> - 2013-10-10 23:12 -0500
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