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Java HotSpot Virtual Machine

JMC 7.1 not recognizing socket write events.

Jeremy WhitingMay 7 2020 — edited May 27 2020


I am a great fan of the JMC tool having used it for a few years.

I switched to using JMC7.1 recently in combination with JDK11.

Using JFR a profile was captured for a Tomcat Http server. HTTPS requests are being processed. Requests are generated using a load driver. The client driver asserts the response contains expected text. So I'm sure the HTTP server is processing requests correctly.

I have noticed with an opened JFR profile after selecting the "Socket I/O" Outline View I am present with a page that should display reads and writes.

Reads I can see.

The issue is Socket Writes are missing completely.

When I look at the "Event Browser" > "Java Application" > "Socket Write" statistics the value is 0. Whereas for "Socket Read" I have 59.

The profile configuration file when using JFR is the bundled "profile.jfc" with JDK11. Here is an excerpt of the configuration file

    <event name="jdk.SocketWrite">

      <setting name="enabled">true</setting>

      <setting name="stackTrace">true</setting>

      <setting name="threshold" control="socket-io-threshold">10 ms</setting>


I looked at the bugs database for JMC project and did not find a reported issue.

Details of my platform are:

$ uname -a

Linux f30lite 5.4.12-100.fc30.x86_64 #1 SMP Wed Jan 15 00:38:53 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux


OpenJDK version used to capture the JFR profile

$ java -version

openjdk version "11.0.5" 2019-10-15

OpenJDK Runtime Environment 18.9 (build 11.0.5+10)

OpenJDK 64-Bit Server VM 18.9 (build 11.0.5+10, mixed mode, sharing)



JDK Mission Control 7.1.0+fedora

(Qualifier: 202003132059, Change id: 9c1257c91ebf)

and CPU

Intel(R) Core(TM) i7-5600U CPU @ 2.60GHz

Is there anything I should check in my configuration or JVM ?



Post Details
Added on May 7 2020
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