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Type:
Improvement
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Status: Resolved
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Priority:
Critical
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Resolution: Won't Fix
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Affects Version/s: 73.21.1
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Component/s: Technical / Transverse
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Tags:
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Sprint:NOS 10.3.6
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Story Points:2
On 09/20/2018 we experienced performance issues, seemingly related to a "coarse lock" in Tomcat's classLoader. eg:
pool-1002-thread-24 - priority:5 - threadId:0x00007f3f00459800 - nativeId:0x2ee - state:BLOCKED stackTrace: java.lang.Thread.State: BLOCKED (on object monitor) at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1769) - waiting to lock <0x00000005c0023fe8> (a org.nuxeo.runtime.tomcat.NuxeoWebappClassLoader) at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1735) at com.thoughtworks.xstream.core.util.CompositeClassLoader.loadClass(CompositeClassLoader.java:136) at java.lang.Class.forName0(Native Method) at java.lang.Class.forName(Class.java:348) at com.thoughtworks.xstream.XStream.buildMapperDynamically(XStream.java:623) at com.thoughtworks.xstream.XStream.buildMapper(XStream.java:596) at com.thoughtworks.xstream.XStream.<init>(XStream.java:568) at com.thoughtworks.xstream.XStream.<init>(XStream.java:496) at com.thoughtworks.xstream.XStream.<init>(XStream.java:465) at com.thoughtworks.xstream.XStream.<init>(XStream.java:411) at com.thoughtworks.xstream.XStream.<init>(XStream.java:378) at com.nuxeo.studio.core.builders.AbstractFeatureBuilder$1.<init>(AbstractFeatureBuilder.java:104) at com.nuxeo.studio.core.builders.AbstractFeatureBuilder.getBareXStream(AbstractFeatureBuilder.java:104) at com.nuxeo.studio.core.builders.AbstractFeatureBuilder.initializeXStream(AbstractFeatureBuilder.java:139) at com.nuxeo.studio.core.builders.AbstractFeatureBuilder.getXStream(AbstractFeatureBuilder.java:180) at com.nuxeo.studio.core.builders.AbstractFeatureBuilder.read(AbstractFeatureBuilder.java:187) at com.nuxeo.studio.core.builders.AbstractFeatureBuilder.readFile(AbstractFeatureBuilder.java:199) at com.nuxeo.studio.core.buildservices.FeatureServiceImpl.getFeature(FeatureServiceImpl.java:229) at com.nuxeo.studio.core.buildservices.FeatureServiceImpl.lambda$getFeatures$0(FeatureServiceImpl.java:309) at com.nuxeo.studio.core.buildservices.FeatureServiceImpl$$Lambda$141/1237593768.run(Unknown Source) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) at java.lang.Thread.run(Thread.java:748)
To reduce the risk of congestion on the class loader lock, we should reduce the number of threads using it.
In FeatureServiceImpl#getFeatures), we are spawning threads to parse the features in parallel. For almost every project, we end up creating at least 24 threads due to how the number is computed.
We propose instead that we use the fixed number of 8 threads for each project, and consider a small project to have under 80 features.
These values could be tweaked in the future.
