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

[Alan Bateman]

On Tue, 6 Jun 2023 19:39:31 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

src/java.base/share/classes/java/net/Socket.java line 1101:

> 1099:         @Override
> 1100:         public int read(byte[] b, int off, int len) throws IOException {
> 1101:             if (! SocketReadEvent.enabled()) {

Drop the space in "! SocketReadEvent" as it is inconsistent with the existing code.

src/java.base/share/classes/jdk/internal/event/SocketReadEvent.java line 119:

> 117:     public static void checkForCommit(long start, long nbytes, SocketAddress remote, long timeout) {
> 118:         long duration = timestamp() - start;
> 119:         if (shouldCommit(duration)) {

I think you know this, but this will need to be re-examined for SocketChannel configured non-blocking.

src/java.base/share/classes/sun/nio/ch/SocketChannelImpl.java line 408:

> 406:     @Override
> 407:     public int read(ByteBuffer buf) throws IOException {
> 408:         if (!SocketReadEvent.enabled()) {

The read/write with sun.nio.ch.SocketInputStream and SocketOutputStream does not go through SC.read/write so I think SocketAdaptor read/write will need attention, maybe a future PR as there are other code paths that aren't covered in this PR.

src/java.base/share/classes/sun/nio/ch/SocketChannelImpl.java line 416:

> 414:             nbytes = implRead(buf);
> 415:         } finally {
> 416:             SocketReadEvent.checkForCommit(start, nbytes, getRemoteAddress(), 0);

This will need to be changed to use remoteAddress(), can't use getRemoteAddress() as it might throw.

src/java.base/share/classes/sun/nio/ch/SocketChannelImpl.java line 466:

> 464:         throws IOException
> 465:     {
> 466:         if (! SocketReadEvent.enabled()) {

Spurious space here too, several other places.

src/java.base/share/classes/sun/nio/ch/SocketChannelImpl.java line 474:

> 472:             nbytes = implRead(dsts, offset, length);
> 473:         } finally {
> 474:             SocketReadEvent.checkForCommit(start, nbytes, getRemoteAddress(), 0);

This has to be remoteAddress() too.

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PR Review Comment: https://git.openjdk.org/jdk/pull/14342#discussion_r1238312001
PR Review Comment: https://git.openjdk.org/jdk/pull/14342#discussion_r1238317470
PR Review Comment: https://git.openjdk.org/jdk/pull/14342#discussion_r1238323035
PR Review Comment: https://git.openjdk.org/jdk/pull/14342#discussion_r1238318572
PR Review Comment: https://git.openjdk.org/jdk/pull/14342#discussion_r1238318875
PR Review Comment: https://git.openjdk.org/jdk/pull/14342#discussion_r1238319120