[technology-pmc] Committer Election for Nazim Bhuiyan on Eclipse OpenJ9

[Eclipse Foundation <emo@xxxxxxxxxxxxxxxxxxxxxx>]

A Committer election for Nazim Bhuiyan on project Eclipse OpenJ9
(technology.openj9) was started by Daryl Maier with this criteria:

Nazim Bhuiyan has been an active contributor to the Eclipse OpenJ9 project
since 2018.

Nazim is the foremost expert in the JIT method inliner optimization, which is
arguably the most influential JIT optimization in OpenJ9 due to its direct
effect on performance and by enabling opportunities for other optimizations.
The inliner is a complex component due to its heuristic policies and inlining
mechanics.  Nazim has investigated a number of Java performance issues over
the years that resulted in changes to the inlining heuristics to catch or
filter opportunities, all while not regressing existing performance (which is
always a challenge with heuristic-based optimizations).  In addition to
developing a deep understanding of its internals and operations, Nazim has
made significant progress over the past few years to make the code more
understandable for others, maintainable, and reducing technical debt.  For
example, earlier this year, Nazim prepared and delivered a deep dive talk
titled "Demystifying the OpenJ9 JIT Inliner" [1] for the OpenJ9 community.

Nazim has also made significant contributions to support OpenJDK Lambdaforms
in OpenJ9, primarily in the JIT component.  This is a large undertaking to
replace the bespoke OpenJ9 MethodHandle implementation (which has a number of
maintenance and performance shortcomings) and standardize it with the
technology developed in the OpenJDK class library.  Achieving good
MethodHandle performance is largely a method inlining exercise, and Nazim has
leveraged his deep skills in the JIT inliner to deliver steady improvements
to make this migration successful.  Noteworthy pull requests include:

* Laying the groundwork for OpenJDK MH support [2]
* VarHandle inlining support [3]
* Inlining improvements related to VarHandles/Foreign Memory [4]
* Inliner improvements for new java/lang/reflect implementation using
MethodHandles (JDK21+) [5][6]

Because MethodHandle usage is growing in recent JDK levels, there has been an
increase in the number of performance problems attributed to that usage.
Nazim is often the JIT person triaging those issues and understanding how
best to resolve them.  For example, he recently implemented several changes
for MethodHandles in order to pass down the known object/type information
needed to optimize past the VarHandle chains, as well as work to improve
MethodHandle.invokeBasic and MethodHandle.linkTo* performance [7].

To improve developer awareness of the Lambdaform Method Handle implementation
in OpenJ9 and to share his diagnostic best practices with others, Nazim
co-authored and delivered a pair of presentations for the OpenJ9 community
[8][9].

Nazim was also responsible for the initial port of the JIT to Intel macOS,
which was a critical component to deliver OpenJ9 support on macOS. Most of
this work was in the JIT runtime (written in assembly), and involved
evaluating different alternatives for supporting the runtime on different x86
operating systems with different tool chains with minimal effort. Nazim
ultimately consolidated the runtime code to use the Netwide Assembler (NASM)
so the same code could build unmodified on Linux, Windows, and macOS with a
single toolchain [10].

To date, Nazim has authored more than 100 pull requests in OpenJ9 [11] and
has demonstrated thoroughness in his implementation and quality assurance of
each of those contributions. He has also formally reviewed 15 pull requests
[12] and has been indirectly involved in shaping many others.

For these reasons, I strongly believe Nazim Bhuiyan is highly deserving of
committer status for the Eclipse OpenJ9 project.

[1] https://youtu.be/OTPJ0XvpbhM?si=_Zmu-XE782u2ykX6
[2] https://github.com/eclipse-openj9/openj9/pull/10607
[3] https://github.com/eclipse-openj9/openj9/pull/18755
[4] https://github.com/eclipse-openj9/openj9/pull/20146
[5] https://github.com/eclipse-openj9/openj9/pull/23223
[6] https://github.com/eclipse-openj9/openj9/pull/23034
[7] https://github.com/eclipse-openj9/openj9/pull/12341
[8] https://youtu.be/kEzBsFoV9PQ?si=oQfOYsyHcomeXN3A
[9] https://youtu.be/wybLPSNbHrA?si=HluFcar2GiOPBbYT
[10] https://github.com/eclipse-openj9/openj9/issues/3148
[11]
https://github.com/eclipse-openj9/openj9/pulls?q=is%3Apr+author%3Anbhuiyan
[12]
https://github.com/eclipse-openj9/openj9/pulls?q=is%3Apr+reviewed-by%3Anbhuiyan+-author%3Anbhuiyan+

Eclipse OpenJ9 project committers can click the election link below to vote.

Election: Election for Nazim Bhuiyan as Committer on Eclipse OpenJ9 [1]

Project: Eclipse OpenJ9 [2]

[1]  
https://projects.eclipse.org/projects/technology.openj9/elections/election-nazim-bhuiyan-eclipse-openj9
[2] https://projects.eclipse.org/projects/technology.openj9