[OSM-dev] How is Mapnik Performances ?

[Roberto Navoni]

Roberto Navoni ha scritto:
Hi Jon,
We found the problem ;) Good I put the comment on convert and the render 
go fast ;)
Thanks for your support :)
Do you know I can update the old one version of mapnik with the new one ?
Best Regards
Roberto
> Jon Burgess ha scritto:
>   
>> On Tue, 2009-01-06 at 00:58 +0000, Roberto Navoni wrote:
>>   
>>     
>>> Jon Burgess ha scritto:
>>>     
>>>       
>>>> On Mon, 2009-01-05 at 20:46 +0000, Roberto Navoni wrote:
>>>>   
>>>>       
>>>>         
>>>>> Hi,
>>>>> I have a question for OSM-Developer ;)
>>>>> So I'm trying mapnik for render italian OSM planet , but the performance 
>>>>> on my sandbox is not so god . I'm using an old one hp laptop that use 
>>>>> Ubuntu 8.04 as SO and as hardware use P4 3 Ghz 1 GByte of ram . I see 
>>>>> that actualy are rendering only two  tile for second.  I'm usining 
>>>>> postgress 8.3 as db. Are there some optimization for speed up the render 
>>>>> time.
>>>>> How many mapnik i can start on a single cpu ? The performance is better ?
>>>>>     
>>>>>         
>>>>>           
>>>> Are you using generate_tiles.py for rendering your tiles?
>>>>   
>>>>       
>>>>         
>>> Yes I use generate tiles
>>>     
>>>       
>>>> Is the web server under your control or are you serving static files via
>>>> a 3rd party web host?
>>>>
>>>>   
>>>>       
>>>>         
>>> I'm doing some test on my server ... I have complete control on it , I'm 
>>> using Ubuntu 8.04 as Operating systems ..
>>>     
>>>       
>>>> The main tile.openstreetmap.org server uses mod_tile[1] which uses
>>>> several optimisation tricks to improve the performance but you can only
>>>> get the full benefit of this if you can install a custom Apache module.
>>>>
>>>>   
>>>>       
>>>>         
>>> Ok ... now  I try It.
>>>     
>>>       
>>>> - multithreaded rendering (should exploit improve efficiency if you have
>>>> hyperthreading in your CPU).
>>>> - rendering and storing tiles in "meta-tiles" (8x8 at once).
>>>> - rendering on-demand, avoiding the need to pre-render lots of tiles
>>>>
>>>> If you can't install the Apache module then the mod_tile render daemon
>>>> can be used standalone with the speedtest & convert_meta tools to
>>>> generate a tree containing plain PNG files for uploading to a 3rd party
>>>> web host. I can provide more details if you are interested in this.
>>>>
>>>> Last time I benchmarked the tile.openstreetmap.org server it was
>>>> rendering approximately 600 tiles/s using 2 x dual core Opteron CPUs.
>>>>   
>>>>       
>>>> The osm.xml file has got significantly more complex since I did those
>>>> tests so the numbers are probably a bit slower now. Even so, your P4
>>>> should manage more than 10 times your current performance.
>>>>
>>>>   
>>>>       
>>>>         
>>> Strange .. is possible that there're some problem on db configuration ?
>>>     
>>>       
>> Possibly but postgres is not normally the bottleneck.
>>
>>   
>>     
>>>  
>>> With top I see the cpu usage by thread and i see that postgress using 15 
>>> % of cpu and mapnik use only 12% of cpu ... is possible that there're 
>>> some setting to change on postgress or on mapnik ?
>>>     
>>>       
>> Some CPU is taken by the "convert" step. Since this is a short lived
>> process it does generally appear in top.
>>
>> If you want to test, simply comment out the following lines in
>> generate_tiles.py and see how much faster it goes:
>>
>>     command = "convert  -colors 255 %s %s" % (tile_uri,tile_uri)
>>     call(command, shell=True)
>>
>> For serving tiles you really want to use 256 colours since the tiles are
>> much smaller. If you are using a recent build of Mapnik then this
>> includes a faster colour conversion algorithm, just change the format
>> from png to png256 a line earlier:
>>
>>     view.save(tile_uri,'png256')
>>
>> Jon
>>
>>   
>>     
> Thank for your reply I see that convert use cpu with top for some times 
> ... now I try do you know how i can update Mapnik 4.0 to the new one ?
> Best Regards
> Roberto
>   
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