Il 03/05/2022 07:25, Rémy Maucherat ha scritto:
On Tue, May 3, 2022 at 6:24 AM Cay Horstmann <cay.horstm...@gmail.com> wrote:
Hi, I am trying to experiment with Loom
(https://openjdk.java.net/jeps/425) virtual threads in Tomcat 10. There
is a nice extension point in server.xml where I can provide an Executor
and use it in the default Connector. It works like a charm--all my
requests run on a virtual thread, and AFAIK, nothing else does.
There is just one issue. It takes forever for Tomcat to execute the
virtual threads. I made a timestamp for each invocation of
public void execute(Runnable command)
called from org.apache.tomcat.util.net.AbstractEndpoint.processSocket
When I fire 1000 simultaneous requests, I can see that method being
invoked 1000 times, but it takes a while to work through the requests.
The last invocation occurs two minutes (!) from the sending of the requests.
When using the org.apache.catalina.core.StandardThreadExecutor, that
many requests are handled in 3 seconds.
Is there something that I am overlooking? I had hoped that execute would
be called near-instantly 1000 times, and then the Loom virtual threads
could show their mettle and execute concurrently.
I wanted to experiment with Loom, but most likely the current Tomcat
NIO(2) connector is not nice for that. I was thinking that
resurrecting the java.io code (actually: writing a new java.io
connector) could be a slightly better plan, but to be honest I don't
expect very good results. I wasn't planning to do it immediately since
Loom is so experimental right now.
Thanks for your fast response. I am wondering what issue you see with
that connector. I am not changing the threading for the NIO part. Only
when a socket is connected, a Loom thread is created.
I tried reading through the code of NioEndpoint/AbstractEndpoint (which
I find on the call stack of the call to execute in my executor). I can't
find anything that throttles the acceptance. I don't think that there
would necessarily be a huge win with Loom, but I am baffled why it is
doing so much worse.
Cheers,
Cay
--
Cay S. Horstmann | http://horstmann.com | mailto:c...@horstmann.com
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