Hi Bernd, why do you think it is measuring a short workload? 'short' in which terms? The overall test suite takes roughly 3 minutes but can be increased easily via increasing the number of road routing queries. BTW: with routing.mean we measure the latency of every road routing query, at least I think so ;)
> Did you check the verbose GC logs, and how many CPUs does Java see/use? Nothing suspicious in the GC logs <https://gist.github.com/karussell/94848aa48244252c6010018b3621b565> IMO, except that G1 produces much more output. Still this reminded me of another mistake <http://stackoverflow.com/q/38905739/194609> I made recently (not disabling swapping) and so I went to my dev server (instead of laptop) where this is already done and have more RAM there (32g), still using just 1000m and the results are a bit better: 320ms vs. only 235ms, so G1 is only ~25% slower. What differences are expected here ... let's say 'maximum'? BTW: CPU usage on the server is roughly 200-240% for G1 and 100-120% for the parallel GC, so the speedup might be also related to the CPUs as the laptop only has 2 cores without hyperthreading. Regards Peter On 31.10.2016 20:52, Bernd Eckenfels wrote: > Hello, > > Since this is measuring a short workload after vom startup it might > not be the best benchmark, but then again throughput GC is expected to > be faster than G1. > > In the particular case however I guess you could tune G1 a bit to that > workload. Did you check the verbose GC logs, and how many CPUs does > Java see/use? > > Gruss > Bernd > -- > http://bernd.eckenfels.net > > > > > On Mon, Oct 31, 2016 at 8:38 PM +0100, "Peter" <graphhop...@gmx.de > <mailto:graphhop...@gmx.de>> wrote: > > Hi, > > I've stumbled today* over a big speed difference for code > execution with G1 GC vs. parallel GC also in the latest JDK8 > (1.8.0_111-b14). Maybe you have interests to investigate this. You > should be able to reproduce this via: > > # setup > git clone https://github.com/graphhopper/graphhopper > wget http://download.geofabrik.de/europe/germany/bayern-latest.osm.pbf > cd graphhopper > > # run measurement > export JAVA_OPTS="-XX:+UseParallelGC -Xmx1000m -Xms1000m" > # the graphhopper.sh script just makes the installation of maven > and bundling the jar a bit simpler > # you can also execute the tests in the class Measurement.java > > <https://github.com/graphhopper/graphhopper/blob/master/tools/src/main/java/com/graphhopper/tools/Measurement.java> > ./graphhopper.sh clean > ./graphhopper.sh measurement berlin-latest.osm.pbf > # now a measurement-<some date>.properties is created: > grep routing.mean measurement-XY.properties > > Now this should print a line where the value is in ms. E.g. I get > ~450ms for the parallel GC and ~780ms for G1GC (on an old laptop). > When I increase the Xmx for the G1 run to 1400m the results do NOT > get closer to parallel GC! > > Let me know if you need more information! > > Regards > Peter > > * > https://github.com/graphhopper/graphhopper/issues/854 > > -- > GraphHopper.com - fast and flexible route planning > -- GraphHopper.com - fast and flexible route planning
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