"VM Thread" taking 100% CPU?

[Yang <te...@gmail.com>]

I'm running my cassandra cluster (one node), it went fine for a while
under heavy load , using 270% CPU etc (this is a multi-core machine).
but after a while, the CPU utilization dropped to 100%, and the
cluster stopped responding to requests.

I did a jstack , and did

ps ax -L -o tid,pid,%cpu,command|less


I found that one thread is taking 45% of CPU, and the corresponding
entry in the jstack output is:


"VM Thread" prio=10 tid=0x09a50400 nid=0x1a1a runnable


what is the "VM Thread" ?
youkit dump does not show a thread with this name

Thanks
Yang

Re: "VM Thread" taking 100% CPU?

[Yang <te...@gmail.com>]

never mind, I found it,
I was trying to dump out the entire keyspace of 1mil rows, which is
not that big, but somehow caused the GC to bring down the server

http://stackoverflow.com/questions/3895940/what-does-java-vm-thread-do

On Thu, Aug 4, 2011 at 1:02 PM, Yang <te...@gmail.com> wrote:
> I'm running my cassandra cluster (one node), it went fine for a while
> under heavy load , using 270% CPU etc (this is a multi-core machine).
> but after a while, the CPU utilization dropped to 100%, and the
> cluster stopped responding to requests.
>
> I did a jstack , and did
>
> ps ax -L -o tid,pid,%cpu,command|less
>
>
> I found that one thread is taking 45% of CPU, and the corresponding
> entry in the jstack output is:
>
>
> "VM Thread" prio=10 tid=0x09a50400 nid=0x1a1a runnable
>
>
> what is the "VM Thread" ?
> youkit dump does not show a thread with this name
>
> Thanks
> Yang
>