The paper I found about pregel are not very detailed, is it "http://portal.acm.org/citation.cfm?id=1582716.1582723";? I guess, in this paper, vertices are assumed to be all actived at every superstep. simply random access will reduce some communication cost but take more superstep. However, is there any way of vertice selection method can be performed that at every super step, each vertex knows whether to active according to information it kept and received from other vertex? But I can't found more detail from that paper... Becides, I can not access your blogs. Would you please send me your article?
Thank you very much! from Xiong Chenyan 在2010-07-02 20:04:40，"Felix Halim" <[email protected]> 写道： >Exactly how to activate a particular vertex is not clear from the >paper (is it random access?) and this feature is probably not as good >as it sounds for complex graph algorithms. It might be better off to >assume all vertices are active (to reduce the overhead of the flag >needed and the space to make it randomly accessible, by storing it in >blocks or whatever). > >Here is my argument: > >The way Pregel (and existing MR) works is iterative, where each >iteration is separated by a super-step barrier where all messages have >to arrive. Algorithms that have fewer super-steps are preferable than >those that have large number of super-steps. In fact, we should >measure Algorithms in terms of the number of super-steps required. To >minimize the number of super-steps, likely we need to activate as much >vertices as possible to do all the work in current super-step, rather >than spill-over to the next super-step. In this case, the feature to >"turn off" vertices is useless, since most of the time all vertices >will be active to effectively reduce the number of super-steps. > >Unfortunately, I don't have experiments to backup my argument... I >don't have Pregel... > >Felix Halim > > >On Fri, Jul 2, 2010 at 7:37 PM, Claudio Martella ><[email protected]> wrote: >> I did too. See: >> >> http://blog.acaro.org/entry/pregel-is-out-but-what-is-pregel >> >> >> Felix Halim wrote: >>> I have. See my comment in this blog: >>> >>> http://blog.udanax.org/2010/06/summary-of-google-pregel.html >>> >>> Felix Halim >>> >>> >>> On Tue, Jun 8, 2010 at 4:00 AM, Mark Kerzner <[email protected]> wrote: >>> >>>> Hi, >>>> >>>> anybody has read it? >>>> >>>> Thank you, >>>> Mark >>>> >>>> >>> >>> >> >> >> -- >> Claudio Martella >> Digital Technologies >> Unit Research & Development - Analyst >> >> TIS innovation park >> Via Siemens 19 | Siemensstr. 19 >> 39100 Bolzano | 39100 Bozen >> Tel. +39 0471 068 123 >> Fax +39 0471 068 129 >> [email protected] http://www.tis.bz.it >> >> Short information regarding use of personal data. According to Section 13 of >> Italian Legislative Decree no. 196 of 30 June 2003, we inform you that we >> process your personal data in order to fulfil contractual and fiscal >> obligations and also to send you information regarding our services and >> events. Your personal data are processed with and without electronic means >> and by respecting data subjects' rights, fundamental freedoms and dignity, >> particularly with regard to confidentiality, personal identity and the right >> to personal data protection. At any time and without formalities you can >> write an e-mail to [email protected] in order to object the processing of >> your personal data for the purpose of sending advertising materials and also >> to exercise the right to access personal data and other rights referred to >> in Section 7 of Decree 196/2003. The data controller is TIS Techno >> Innovation Alto Adige, Siemens Street n. 19, Bolzano. You can find the >> complete information on the web site www.tis.bz.it. >> >> >>
