Did you upgrade from a previous version? DId you make some schema changes like compaction strategy, compression, bloom filter, etc.?What about the R/W requests? SharedPool Workers are... shared ;-) Put logs in debug to see some examples of what services are using this pool (many actually).
Best, Romain Le Mercredi 13 juillet 2016 18h15, Patrick McFadin <pmcfa...@gmail.com> a écrit : Might be more clear looking at nodetool tpstats >From there you can see all the thread pools and if there are any blocks. Could >be something subtle like network. On Tue, Jul 12, 2016 at 3:23 PM, Aoi Kadoya <cadyan....@gmail.com> wrote: Hi, I am running 6 nodes vnode cluster with DSE 4.8.1, and since few weeks ago, all of the cluster nodes are hitting avg. 15-20 cpu load. These nodes are running on VMs(VMware vSphere) that have 8vcpu (1core/socket)-16 vRAM.(JVM options : -Xms8G -Xmx8G -Xmn800M) At first I thought this is because of CPU iowait, however, iowait is constantly low(in fact it's 0 almost all time time), CPU steal time is also 0%. When I took a thread dump, I found some of "SharedPool-Worker" threads are consuming CPU and those threads seem to be waiting for something so I assume this is the cause of cpu load. "SharedPool-Worker-1" #240 daemon prio=5 os_prio=0 tid=0x00007fabf459e000 nid=0x39b3 waiting on condition [0x00007faad7f02000] java.lang.Thread.State: WAITING (parking) at sun.misc.Unsafe.park(Native Method) at java.util.concurrent.locks.LockSupport.park(LockSupport.java:304) at org.apache.cassandra.concurrent.SEPWorker.run(SEPWorker.java:85) at java.lang.Thread.run(Thread.java:745) Thread dump looks like this, but I am not sure what is this sharedpool-worker waiting for. Would you please help me with the further trouble shooting? I am also reading the thread posted by Yuan as the situation is very similar to mine but I didn't get any blocked, dropped or pending count in my tpstat result. Thanks, Aoi