Moses-support Digest, Vol 105, Issue 49

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Today's Topics:

1. Re: Performance issues using Moses Server with Moses 3 (Oren)


----------------------------------------------------------------------

Message: 1
Date: Thu, 23 Jul 2015 17:06:09 +0300
From: Oren <mooshified@gmail.com>
Subject: Re: [Moses-support] Performance issues using Moses Server
with Moses 3
To: Barry Haddow <bhaddow@staffmail.ed.ac.uk>
Cc: "moses-support@mit.edu" <moses-support@mit.edu>
Message-ID:
<CAHWEG_XhjyewuzxBXdzOT+7PrWEWs=+HSka3Mv4RgKWNeVoByw@mail.gmail.com>
Content-Type: text/plain; charset="utf-8"

More details...

Our NFS is mounted at /mnt/storage .

The command to run moses server is:

/mnt/storage/Common/mosesdecoder3/bin/mosesserver -f
/mnt/storage/Common/models/translation_models/moses3_model/mert-work/moses.ini
mark-unknown -xml-input -threads 18 exclusive

Here is the complete moses.ini (excluding comments):

[input-factors]
0

[mapping]
0 T 0

[distortion-limit]
6

[feature]
UnknownWordPenalty
WordPenalty
PhrasePenalty
PhraseDictionaryMemory name=TranslationModel0 num-features=4
path=/mnt/storage/Common/models/translation_models/moses3_model/train/model/phrase-table.gz
input-factor=0 output-factor=0
LexicalReordering name=LexicalReordering0 num-features=6
type=wbe-msd-bidirectional-fe-allff input-factor=0 output-factor=0
path=/mnt/storage/Common/models/translation_models/moses3_model/train/model/reordering-table.wbe-msd-bidirectional-fe.gz

Distortion
KENLM lazyken=0 name=LM0
path=/mnt/storage/Common/models/language_models/langmod.5gram.blm order=5


[threads]
6

[weight]

LexicalReordering0= 0.0268311 -0.0146878 0.0261305 0.0380759 0.0118265
0.07479
Distortion0= 0.074665
LM0= 0.0972206
WordPenalty0= -0.18469
PhrasePenalty0= -0.212528
TranslationModel0= 0.0184105 0.091358 0.112618 0.0161682
UnknownWordPenalty0= 1


On Wednesday, July 22, 2015, Oren <mooshified@gmail.com> wrote:

> Yes, we use a lot of RAM in our setup. But the improved response time
> justifies it.
>
> Our language is on a nfs, bit we've been working this way with moses 1 for
> some time with no problems (ten different machines using the same language
> model file over nfs). Same for the reordering model. Neither of them is in
> memory. Raising these models into memory will require raising our already
> excessive RAM requirements...
>
> Thanks again for the help.
>
> On Wednesday, July 22, 2015, Barry Haddow <bhaddow@staffmail.ed.ac.uk
> <javascript:_e(%7B%7D,'cvml','bhaddow@staffmail.ed.ac.uk');>> wrote:
>
>> Hi Oren
>>
>> I'm not aware of any threading problems with PhraseDictionaryMemory, but
>> not many people use it since it takes up too much memory. Moses command
>> line runs multi-threaded using a thread pool.
>>
>> Is your language model on a local file system? Running it over nfs can be
>> bad. What about your reordering model? Are you using the compact or the
>> memory version?
>>
>> cheers - Barry
>>
>> On 22/07/15 15:09, Oren wrote:
>>
>> We have no swapping issues. I was asking if the use of an in-memory
>> translation model might cause multithreading problems.
>>
>>
>> I'm not sure how to replicate the problem on cmd moses, since it's
>> purely a multithreading issue. Ca you run cmd moses multithreaded?
>>
>> I can't attach the complete moses.ini because it's on a separate
>> network... But I copied below the stuff that looked relevant. I also tried
>> to change the [threads] setting to 18, with no apparent effect.
>>
>> [input-factors]
>> 0
>>
>> [mapping]
>> 0 T 0
>>
>> [distortion-limit]
>> 6
>>
>> [feature]
>> UnknownWordPenalty
>> WordPenalty
>> PhrasePenalty
>> PhraseDictionaryMemory name=TranslationModel0 num-features=4
>> path=<path>/phrase-table.gz input-factor=0 output-factor=0
>> LexicalReordering <parameters>
>> Distortion
>> KENLM lazyken=0 name=LM0 path=<path> order=5
>>
>> [threads]
>> 6
>>
>> [weight]
>>
>> <weight parameters>
>>
>> On Tuesday, July 21, 2015, Hieu Hoang <hieuhoang@gmail.com> wrote:
>>
>>> is it possible you can make your moses.ini file available for us to see?
>>>
>>> do you know if the same problem occurs if you use the command line
>>> moses, rather than mosesserver?
>>>
>>>
>>> Hieu Hoang
>>> Researcher
>>> New York University, Abu Dhabi
>>> http://www.hoang.co.uk/hieu
>>>
>>> On 21 July 2015 at 18:07, Barry Haddow <bhaddow@staffmail.ed.ac.uk>
>>> wrote:
>>>
>>>>
>>>> On 21/07/15 14:51, Oren wrote:
>>>>
>>>> I am using the in-memory mode, using about 50GB of RAM. (No swap issues
>>>> as far as I can tell.) Could that cause issues?
>>>>
>>>>
>>>> Yes, swapping would definitely cause issues - was that your question?
>>>>
>>>>
>>>>
>>>> I looked at the commit you linked to, but it doesn't seem to be
>>>> something configurable beyond the -threads switch. Am I missing something?
>>>>
>>>>
>>>> The commit enables you to set the maximum number of connections to be
>>>> the same as the maximum number of threads.
>>>>
>>>>
>>>> On Tuesday, July 21, 2015, Barry Haddow <bhaddow@staffmail.ed.ac.uk>
>>>> wrote:
>>>>
>>>>> Hi Oren
>>>>>
>>>>> Does your host have 18 threads available? It could also be that
>>>>> xmlrpc-c is limiting the number of connections - this can now be configured:
>>>>>
>>>>> https://github.com/moses-smt/mosesdecoder/commit/b3baade7f022edbcea2969679a40616683f63523
>>>>>
>>>>> Slowdowns in Moses are often caused by disk access bottlenecks. You
>>>>> can use --minphr-memory and --minlexr-memory to make sure that the phrase
>>>>> and reordering tables are loaded in to memory, rather than being access
>>>>> on-demand. Make sure your host has enough RAM and is not swapping. As I
>>>>> mentioned before there are various ways to make your models smaller (
>>>>> http://www.statmt.org/moses/?n=Advanced.RuleTables), which can make a
>>>>> big difference to speed depending on your setup.
>>>>>
>>>>> cheers - Barry
>>>>>
>>>>> On 21/07/15 09:30, Oren wrote:
>>>>>
>>>>> Hi Barry,
>>>>>
>>>>> Thanks for the quick response.
>>>>>
>>>>> I added the switch "-threads 18" to the command to raise moses
>>>>> server. The slowness issue persists but in a different form. Most requests
>>>>> return right away, even under heavy load, but some requests (about 5%) take
>>>>> far longer - about 15-20 seconds.
>>>>>
>>>>> Perhaps there are other relevant switches?
>>>>>
>>>>> Thanks again.
>>>>>
>>>>> On Monday, July 20, 2015, Barry Haddow <bhaddow@staffmail.ed.ac.uk>
>>>>> wrote:
>>>>>
>>>>>> Hi Oren
>>>>>>
>>>>>> The threading model is different. In v1, the server created a new
>>>>>> thread for every request, v3 uses a thread pool. Try increasing the number
>>>>>> of threads.
>>>>>>
>>>>>> Also, make sure you use the compact phrase table and KenLM as they
>>>>>> are normally faster, and pre-pruning your phrase table can help,
>>>>>>
>>>>>> cheers - Barry
>>>>>>
>>>>>> On 20/07/15 12:01, Oren wrote:
>>>>>>
>>>>>> Hi all,
>>>>>>
>>>>>> We are in the process of migrating from Moses 1 to Moses 3. We have
>>>>>> noticed a significant slowdown when sending many requests at once to Moses
>>>>>> Server. The first request will actually finish about 25% faster that a
>>>>>> single request using Moses 1, but as more requests accumulate there is a
>>>>>> marked slowdown, until requests take 5 times longer or more.
>>>>>>
>>>>>> Is this a known issue? Is it specific to Moses Server? What can we
>>>>>> do about it?
>>>>>>
>>>>>> Thanks!
>>>>>>
>>>>>> Oren.
>>>>>>
>>>>>>
>>>>>> _______________________________________________
>>>>>> Moses-support mailing listMoses-support@mit.eduhttp://mailman.mit.edu/mailman/listinfo/moses-support
>>>>>>
>>>>>>
>>>>>>
>>>>>
>>>>> _______________________________________________
>>>>> Moses-support mailing listMoses-support@mit.eduhttp://mailman.mit.edu/mailman/listinfo/moses-support
>>>>>
>>>>>
>>>>>
>>>>
>>>> The University of Edinburgh is a charitable body, registered in
>>>> Scotland, with registration number SC005336.
>>>>
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>>
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