Well I think you didn't read my last message yet....
I think currently about 6GB of free RAM are needed to have max-area=1024
to be working (assuming max-nodes 900 000). What is the actual maximum?
Could one set max-area=1300? (that is about what I think is max on my
machine with max-nodes 900 000) As more RAM is available in 1-2 years
some people maybe would like to go for max-area 4000 when splitting
Europe (creating a map of the whole world doesn't make sense due to
Garmin limits anyhow).
As it needed 1pass instead of 4, the time improvement was well
worthwhile (about 40% faster).
I think the max-area default could be set to 512, that should need about
as much memory as the old 255, shouldn't it? So it wouldn't break
anything due to out of memory errors for people simply updating the
splitter.
On 17.11.2011 19:29, Gerd Petermann wrote:
Hello Felix,
thanks for trying. I think the most interesting part of the fix is
that it allows to split very large files with a higher max-area value
when memory is an issue. As long as only one pass is needed, the
benefits are rather small.
BUT if you can split europe in two or three passes instaead of 5 or
more the speed is probably much better.
Anyhow, I am no longer sure about my change reg. the default value for
max-areas. I think the old default 255 was better.
On my linux box with -Xmx3200m I still needed two passes with
max-areas=512 for europe.
ciao,
Gerd
>
> some more speed observations:
> country germany.pbf from Geofabrik
>
> splitter_patched with optimize-mem: 3 min 6 seconds
> splitter_patched without optimize-mem: 3min 2 seconds
> old splitter: 3 min 42 seconds
>
> I am currently running against europe.pbf, will post the results later.
> But it seems that the patched mkgmap is consistently a bit faster. I
> think optimize-mem is better of by default though (most people using
> mkgmap/splitter have powerful computers anyhow).
> I'm interested if the 1024 max areas vs the old 255 and subsequent less
> runs make for a bigger speedup than on small(er) extracts.
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