RFR: 8308995: Update Network IO JFR events to be static mirror events [v3]

[Alan Bateman]

On Tue, 27 Jun 2023 21:52:08 GMT, Tim Prinzing <tprinzing at openjdk.org> wrote:

>> The socket read/write JFR events currently use instrumentation of java.base code using templates in the jdk.jfr modules. This results in some java.base code residing in the jdk.jfr module which is undesirable.
>> 
>> JDK19 added static support for event classes. The old instrumentor classes should be replaced with mirror events using the static support.
>> 
>> In the java.base module:
>> Added two new events, jdk.internal.event.SocketReadEvent and jdk.internal.event.SocketWriteEvent.
>> java.net.Socket and sun.nio.ch.SocketChannelImpl were changed to make use of the new events.
>> 
>> In the jdk.jfr module:
>> jdk.jfr.events.SocketReadEvent and jdk.jfr.events.SocketWriteEvent were changed to be mirror events.
>> In the package jdk.jfr.internal.instrument, the classes SocketChannelImplInstrumentor, SocketInputStreamInstrumentor, and SocketOutputStreamInstrumentor were removed. The JDKEvents class was updated to reflect all of those changes.
>> 
>> The existing tests in test/jdk/jdk/jfr/event/io continue to pass with the new implementation:
>> Passed: jdk/jfr/event/io/TestSocketChannelEvents.java
>> Passed: jdk/jfr/event/io/TestSocketEvents.java
>> 
>> I added a micro benchmark which measures the overhead of handling the jfr socket events.
>> test/micro/org/openjdk/bench/java/net/SocketEventOverhead.java.
>> It needs access the jdk.internal.event package, which is done at runtime with annotations that add the extra arguments.
>> At compile time the build arguments had to be augmented in make/test/BuildMicrobenchmark.gmk
>
> Tim Prinzing has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains ten commits:
> 
>  - remove unused SOCKET_READ and SOCKET_WRITE configurations.
>  - Merge branch 'master' into JDK-8308995
>    
>    # Conflicts:
>    #	src/jdk.jfr/share/classes/jdk/jfr/events/EventConfigurations.java
>  - Avoid exceptions getting address/timeout for jfr event. Remove unused
>    EventConiguration fields SOCKET_READ and SOCKET_WRITE.  Remove spurious
>    whitespace.
>  - some changes from review.
>    
>    read0() to implRead()
>    write0() to implWrite()
>    trailing whitespace
>  - fix copyright date
>  - Added micro benchmark to measure socket event overhead.
>  - Some changes from review.
>    
>    Append a 0 to method names being wrapped.  Use getHostString to avoid
>    a reverse lookup when fetching the hostname of the remote address.
>  - remove unnecessary cast
>  - 8308995: Update Network IO JFR events to be static mirror events

src/java.base/share/classes/java/net/Socket.java line 1133:

> 1131:                 return parent.getSoTimeout();
> 1132:             } catch (Throwable t) {
> 1133:                 // ignored - avoiding exceptions in jfr event data gathering

This should be SocketException, not Throwable. That said, I think it would be useful to know why the SocketReadEvent includes the timeout. Is this used to see If read durations are close to the timeout? I assume once this code is fixed to deal with the exceptional case that the need to include the timeout for the success case will mostly go away.

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PR Review Comment: https://git.openjdk.org/jdk/pull/14342#discussion_r1244728684