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Re: [jetty-users] Bottleneck while perf testing on Jetty
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Hi,
On Mon, Apr 16, 2012 at 17:55, Ugo Matrangolo <ugo.matrangolo@xxxxxxxxx> wrote:
> Hi,
>
> I came across in some performance problems while load testing one of my web
> services.
>
> This service has an API that gives back JSON documents keyed by their ids.
> Sometime these JSON documents are really big (~20MB) and takes a while to
> load them.
>
> We setup a load test to see what would happen in a situation where *all* the
> requests are for these large JSON documents and we noticed that the service
> gets slower and slower.
>
> Looking at a thread dump we saw that 80% of our threads are blocked here:
>
> "qtp-84" prio=5 tid=112044000 nid=0x11b6e2000 in Object.wait() [11b6e0000]
> java.lang.Thread.State: TIMED_WAITING (on object monitor)
> at java.lang.Object.wait(Native Method)
> at
> org.eclipse.jetty.io.nio.SelectChannelEndPoint.blockWritable(SelectChannelEndPoint.java:436)
>
> I think that this test is quite unrealistic but I'm curious about this
> bottleneck. Does anyone ran into this problems before??
>
> Any insight ??
You have filled your network bandwidth.
Jetty is waiting to write onto a socket (in blockWritable()) until the
NIO subsystem (OS and JVM) tells that the congestion on the socket(s)
has decreased and that it is possible to write again.
It's not a Jetty bottleneck.
Simon
--
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http://intalio.com
http://bordet.blogspot.com
----
Finally, no matter how good the architecture and design are,
to deliver bug-free software with optimal performance and reliability,
the implementation technique must be flawless. Victoria Livschitz
