Ok. I'll first change the GC and see if the time spent decreased. Than I'll try increasing the heap as Fuad recommends.
On 9/25/09, Mark Miller <markrmil...@gmail.com> wrote: > When we talk about Collectors, we are not just talking about > "collecting" - whatever that means. There isn't really a "collecting" > phase - the whole algorithm is garbage collecting - hence calling the > different implementations "collectors". > > Usually, fragmentation is dealt with using a mark-compact collector (or > IBM has used a mark-sweep-compact collector). > Copying collectors are not only super efficient at collecting young > spaces, but they are also great for fragmentation - when you copy > everything to the new space, you can remove any fragmentation. At the > cost of double the space requirements though. > > So mark-compact is a compromise. First you mark whats reachable, then > everything thats marked is copied/compacted to the bottom of the heap. > Its all part of a "collection" though. > > Jonathan Ariel wrote: >> Maybe what's missing here is how did I get the 11%.I just ran solr with >> the >> following JVM params: -XX:+PrintGCApplicationConcurrentTime >> -XX:+PrintGCApplicationStoppedTime with that I can measure the amount of >> time the application run between collection pauses and the length of the >> collection pauses, respectively. >> I think that in this case the 11% is just for memory collection and not >> defragmentation... but I'm not 100% sure. >> >> On Fri, Sep 25, 2009 at 5:05 PM, Fuad Efendi <f...@efendi.ca> wrote: >> >> >>> But again, GC is not just "Garbage Collection" as many in this thread >>> think... it is also "memory defragmentation" which is much costly than >>> "collection" just because it needs move somewhere _live_objects_ (and >>> wait/lock till such objects get unlocked to be moved...) - obviously more >>> memory helps... >>> >>> 11% is extremely high. >>> >>> >>> -Fuad >>> http://www.linkedin.com/in/liferay >>> >>> >>> >>>> -----Original Message----- >>>> From: Jonathan Ariel [mailto:ionat...@gmail.com] >>>> Sent: September-25-09 3:36 PM >>>> To: solr-user@lucene.apache.org >>>> Subject: Re: FW: Solr and Garbage Collection >>>> >>>> I'm not planning on lowering the heap. I just want to lower the time >>>> "wasted" on GC, which is 11% right now.So what I'll try is changing the >>>> >>> GC >>> >>>> to -XX:+UseConcMarkSweepGC >>>> >>>> On Fri, Sep 25, 2009 at 4:17 PM, Fuad Efendi <f...@efendi.ca> wrote: >>>> >>>> >>>>> Mark, >>>>> >>>>> what if piece of code needs 10 contiguous Kb to load a document field? >>>>> >>> How >>> >>>>> locked memory pieces are optimized/moved (putting on hold almost whole >>>>> application)? >>>>> Lowering heap is _bad_ idea; we will have extremely frequent GC >>>>> >>> (optimize >>> >>>>> of >>>>> live objects!!!) even if RAM is (theoretically) enough. >>>>> >>>>> -Fuad >>>>> >>>>> >>>>> >>>>>> Faud, you didn't read the thread right. >>>>>> >>>>>> He is not having a problem with OOM. He got the OOM because he >>>>>> >>> lowered >>> >>>>>> the heap to try and help GC. >>>>>> >>>>>> He normally runs with a heap that can handle his FC. >>>>>> >>>>>> Please re-read the thread. You are confusing the tread. >>>>>> >>>>>> - Mark >>>>>> >>>>>> >>>>> >>>>>>> GC will frequently happen even if RAM is more than enough: in case >>>>>>> >>> if >>> it >>> >>>>> is >>>>> >>>>>>> heavily sparse... so that have even more RAM! >>>>>>> -Fuad >>>>>>> >>>>> >>>>> >>> >>> >> >> > > > -- > - Mark > > http://www.lucidimagination.com > > > >
