Thanks - I'll try to work through the profiles - hopefully they'll make some sense as I work through them.
osrm-prepare also took two weeks to crash.Perhaps it did have a sudden spike in memory usage before crashing - it was overnight, so I don't know for sure. Anyway I'm not in a rush to try another two week run. Cheers, Richard On Wed, Oct 14, 2015 at 4:20 AM, Daniel Hofmann <[email protected]> wrote: > If osrm-prepare crashed, just add more swap. Also make sure to read this > ticket: >> https://github.com/Project-OSRM/osrm-backend/issues/1698 > > I don't think we have documentation for the profiles. I know they are > somewhat ugly and huge. I would recommend taking a look at the profile's > general structure first, so that you roughly understand e.g. that there are > callbacks for OSM nodes and ways, and what they do. After that I would > simply trace the globals through the script. That is e.g. search for all > places where a certain whitelist is used and build a mental model based on > that. Pen and paper may help :) > >> https://github.com/Project-OSRM/osrm-backend/blob/develop/profiles/car.lua > > You can find the C++ side of things in the extractor directory: >> https://github.com/Project-OSRM/osrm-backend/tree/develop/extractor > > For example, the scripting environment uses luabind to make a few functions > visible, e.g. the get_value_by_key function, that then can be used in the > profiles. The other way, that is using lua functions in C++ is mostly done > in the extractor implementation: I would recommend just searching for the > symbols you want to know more about: > >> >> https://github.com/Project-OSRM/osrm-backend/search?utf8=%E2%9C%93&q=node_function&type=Code > > Cheers, > Daniel > > On Mon, Oct 12, 2015 at 4:00 AM, Richard Marsden <[email protected]> wrote: >> >> It is possible I've just managed to demonstrate this to myself. >> osrm-prepare crashed out on the Europe-wide dataset at the 90+% >> complete level with 30GB swap (16GB real). For much of the run it >> didn't go above about 15GB swap. Very slow of course - but that was to >> be expected. >> >> This continues to be a side / evaluation project, but I'm continuing >> to investigate. Looks like the PC in question should be able to handle >> most countries, but will balk at most continents, and the very largest >> countries (e.g. the US). High-RAM hardware is relatively pricey, but >> it is a possibility in the new year. >> >> Looking at the individual pieces, next I'm going to look at the >> profile.lua file. I've never used LUA before, but that is easy enough >> to remedy with online tutorials and the various books that are >> available. But what about the script that is used by OSRM? Is there >> any documentation as to the variables and/or functions that are >> expected? And the tags used in OSM that the script is expected to >> map? >> >> >> Cheers, >> >> Richard Marsden >> >> On Thu, Sep 17, 2015 at 4:37 PM, Patrick Niklaus >> <[email protected]> wrote: >> > W.r.t. the pre-preprocessing you are correct. >> > >> >> What is that extra power used for? >> > >> > Including all sorts of external data sources. Also the logic in the >> > lua profiles is not just replaceable by simple key-value pairs, OSM >> > requires you to handle a lot of special cases. >> > >> >> Presumably I could do the same for world preparation & routing? Have, >> >> perhaps a 100GB+ swap file, ideally on an SSD. >> > >> > This will fall apart when you have some actual load pressure on the >> > system. We need random access to memory, which will create a lot of >> > page faults (== slow). Even an SSD is not even close to memory speed. >> > >> > You have two options: >> > - split the datasets >> > - get a bigger server >> > >> > Cheers, >> > Patrick >> > >> > >> > On Thu, Sep 17, 2015 at 10:06 PM, Richard Marsden <[email protected]> >> > wrote: >> >> I've been evaluating OSRM, using it primarily as a library from C++. >> >> >> >> I believe I've determined the answer to most of the questions, but I'm >> >> also looking for confirmation. >> >> (I understand the reason for these constraints - the trade-off of >> >> speed vs flexibility) >> >> >> >> First, road speeds are set with 'profile.lua' at the osrm-extract >> >> stage. This filters out unnecessary roads (eg. foot paths for car >> >> routing), but also applies the road speeds. >> >> If I wish to change the speed profile, I need to regenerate the road >> >> network with osrm-extract and osrm-routed. >> >> Correct? >> >> >> >> If I wanted different speeds for the final distance/time calculations, >> >> I could use the returned route, and apply my own speed table according >> >> to the road type of each road segment. This would not, of course, >> >> change the route geometry is calculated. >> >> >> >> If I want a shortest route (distance optimized) instead of a quickest >> >> route (time optimized), I need to set all the road speeds to the same >> >> speed and regenerate the network. I.e. osrm does not directly support >> >> the concept of a "shortest route". >> >> >> >> The profile is provided with a LUA file. I had to look this one up :-) >> >> Looks a useful scripting language, but why is this profile a script >> >> file, and not a simple configuration file of constants (eg. key-value >> >> pairs)? >> >> Seems like an unnecessary complexity - I'd like to understand the >> >> perceived advantages. What is that extra power used for? >> >> >> >> Finally, the memory usage... I saw a reference to the server requiring >> >> 40GB of memory for pan-European routing. Presumably that could be >> >> offset with a large swap file(?) >> >> A large swap file has worked well when I was testing the US-South >> >> region on an 8GB machine. >> >> Presumably I could do the same for world preparation & routing? Have, >> >> perhaps a 100GB+ swap file, ideally on an SSD. >> >> >> >> >> >> Cheers, >> >> >> >> Richard Marsden >> >> >> >> _______________________________________________ >> >> OSRM-talk mailing list >> >> [email protected] >> >> https://lists.openstreetmap.org/listinfo/osrm-talk >> > >> > _______________________________________________ >> > OSRM-talk mailing list >> > [email protected] >> > https://lists.openstreetmap.org/listinfo/osrm-talk >> >> _______________________________________________ >> OSRM-talk mailing list >> [email protected] >> https://lists.openstreetmap.org/listinfo/osrm-talk > > > > _______________________________________________ > OSRM-talk mailing list > [email protected] > https://lists.openstreetmap.org/listinfo/osrm-talk > _______________________________________________ OSRM-talk mailing list [email protected] https://lists.openstreetmap.org/listinfo/osrm-talk
