True.
W dniu 2015-03-12 12:09, Barry Haddow napisał(a): > Hi Marcin > > But the search time that Jesus quotes shouldn't include any translation > option lookup, and therefore shouldn't benefit from phrase table caching, > should it? > > cheers - Barry > > On 12/03/15 11:00, Marcin Junczys-Dowmunt wrote: > Hi Barry, I do have another cache used for decompression in my phrase table. > Maybe that's the reason? It's being shared between threads, so I guess it > gets filled up more quickly than the thread-specific caches. In other words: > I am cheating :) W dniu 2015-03-12 11:11, Barry Haddow napisał(a): Hi Jesús > As Marcin points out, when using the compact phrase table you need to allow > Moses time to cache the translation options for the common phrase pairs. With > the gzipped phrase table, it effectively caches the whole phrase table during > loading, but you excluded this 1800+ seconds from your calculations. I'm > curious why the search time is twice as long for gzipped as opposed to > compact though (3.3s vs 1.6s). Once the translation options are loaded, they > should be doing the same thing shouldn't they? Maybe the reduced process size > with the compact phrase table gives the OS more space to cache LM pages? I'm > not sure how accurate the timings given by Moses are. cheers - Barry On > 11/03/15 19:31, Jesús González Rubio wrote: 2015-03-11 19:21 GMT+00:00 Marcin Junczys-Dowmunt <[email protected] <mailto:[email protected]> <mailto:[email protected] <mailto:[email protected]>>>: Maybe someone will correct me, but if I am not wrong, the gziped version already calculates the future score while loading (i.e. the phrase is being scored by the language model). The compact phrase table cannot do this during loading and doing this on-line. This will be the reason for the slow speed. I suppose your phrase table has not been pruned? So, for instance function words like "the" can have hundreds of thousands of counterparts that need to be scored by the LM during collection. That makes sense. You can limit your phrase table using Barry's prunePhraseTable tool. With this you can limit it to, say, the 20 best phrases (corresponds to the ttable limit) and only score this 20 phrases during collection. That should be orders of magnitude faster. OK. Best, Marcin W dniu 11.03.2015 o 20:12, Jesús González Rubio pisze: Thanks for the quick response, I will try as you suggest. Nevertheless, my main concern is the time spent collecting options. Is it normal the difference observed respect to the gzip'ed tables? being the tables cached, shouldn't they be closer? 2015-03-11 18:52 GMT+00:00 Marcin Junczys-Dowmunt <[email protected] <mailto:[email protected]> <mailto:[email protected] <mailto:[email protected]>>>: Hi, Try measuring the differences again after a full system reboot (fresh reboot before each mesurement) or after purging OS read/write caches. Your phrase tables are most likely cached, which means they are in fact in memory. Best, Marcin W dniu 11.03.2015 o 19:31, Jesús González Rubio pisze: Hi, I'm obtaining some unintuitive timing results when using compact phrase tables. The average translation time per sentence is much higher for them in comparison to using gzip'ed phrase tables. Particularly important is the difference in time required to collect the options. This table summarizes the timings (in seconds): Compact Gzip'ed on-disk in-memory Init: 5.9 6.3 1882.8 Per-sentence: - Collect: 5.9 5.8 0.2 - Search: 1.6 1.6 3.3 Results in the table were computed using Moses v2.1 with one single thread (-th 1) but I've seen similar results using the pre-compiled binary for moses v3.0. The model comprises two phrase-tables (~2G and ~3M), two lexicalized reordering tables (~700M and ~1M) and two language models (~31G and ~38M). You can see the exact configuration in the attached moses.ini file. Interestingly, there is virtually no difference for the compact table between the the on-disk and in-memory options. Additionally, timings were higher for the initial sentences in both cases which I think should not be the case for the in-memory option. May be the case that the in-memory option of compact tables (-minpht-memory -minlexr-memory) is not working properly? Cheers. -- Jesús _______________________________________________ Moses-support mailing list [email protected] <mailto:[email protected]> <mailto:[email protected] <mailto:[email protected]>> http://mailman.mit.edu/mailman/listinfo/moses-support [1] _______________________________________________ Moses-support mailing list [email protected] <mailto:[email protected]> <mailto:[email protected] <mailto:[email protected]>> http://mailman.mit.edu/mailman/listinfo/moses-support [1] -- Jesús _______________________________________________ Moses-support mailing list [email protected] <mailto:[email protected]> http://mailman.mit.edu/mailman/listinfo/moses-support [1] Links: ------ [1] http://mailman.mit.edu/mailman/listinfo/moses-support
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