Hello,
We are perf testing solr 5.5.2 (with a limit test, i.e. sending as much queries/sec as possible) and we see the cpu never goes over 20%, and threads are blocked in org.eclipse.jetty.util.BlockingArrayQueue, as we can see in solr admin interface thread dumps qtp706277948-757 (757) java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject@2c4a56cb - sun.misc.Unsafe.park(Native Method) - java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:215) - java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.awaitNanos(AbstractQueuedSynchronizer.java:2078) - org.eclipse.jetty.util.BlockingArrayQueue.poll(BlockingArrayQueue.java:389) - org.eclipse.jetty.util.thread.QueuedThreadPool.idleJobPoll(QueuedThreadPool.java:531) - org.eclipse.jetty.util.thread.QueuedThreadPool.access$700(QueuedThreadPool.java:47) - org.eclipse.jetty.util.thread.QueuedThreadPool$3.run(QueuedThreadPool.java:590) - java.lang.Thread.run(Thread.java:745) We changed two things in jetty configuration, maxThreads value in /opt/solr/server/solr/jetty.xml <Set name="maxThreads" type="int"><Property name="solr.jetty.threads.max" default="400"/></Set> and we activated the request log, i.e. uncommented the lines <Ref id="Handlers"> <Call name="addHandler"> <Arg> <New id="RequestLog" class="org.eclipse.jetty.server.handler.RequestLogHandler"> <Set name="requestLog"> <New id="RequestLogImpl" class="org.eclipse.jetty.server.NCSARequestLog"> <Set name="filename"> /var/solr/logs/requests.log </Set> <Set name="filenameDateFormat">yyyy_MM_dd</Set> <Set name="retainDays">90</Set> <Set name="append">true</Set> <Set name="extended">false</Set> <Set name="logCookies">false</Set> <Set name="LogTimeZone">UTC</Set> <Set name="logLatency">true</Set> </New> </Set> </New> </Arg> </Call> </Ref> in jetty.xml We had the same result with maxThreads=10000 (default value in solr install). Did anyone experiment the same issue with solr 5? Best regards, Elisabeth