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- Chris Elford -- Intel
Corporation
- Sergey Kuksenko -- Intel Corporation
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2
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- Overall project goals
- Introduction to Apache* Harmony
- The Eclipse* TPTP profiler
- First experiences using TPTP
- Analysis of advanced workload with TPTP
- Looking to the future
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- Goals
- Identify Harmony performance opportunities using TPTP
- Integrate TPTP into our performance methodology
- Approach
- Start simple…
- Verify that we can recognize known performance issues w/ TPTP
- Understand how opportunities manifest in TPTP
- Understand current limitations of TPTP and Harmony JVMTI
- Fix critical issues along the way
- Grow…
- Move forward looking for new opportunities to optimize Harmony
- Use TPTP more regularly
- Suggest TPTP & Harmony JVMTI enhancements for our use case
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- Why J2SE 5?
- “Starting with Java SE 5, as that is the first version of Java SE for
which the licensing allows an open source implementation”
- “Continue with Java SE 6 and any subsequent versions that follow.”
- Who all is using Apache* Harmony technology?
- Since its an open license, we don’t know for sure… but to name a few
- http://mail-archives.apache.org/mod_mbox/harmony-dev/200712.mbox/%3c4759E2CD.5010308@gmail.com%3e
- http://mail-archives.apache.org/mod_mbox/harmony-dev/200711.mbox/%3c8084e12c0711201546m7e3cc028kf5df2763df708fd3@mail.gmail.com%3e
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- May 2005: Accepted by the ASF and started in Apache* Incubator
- May 2006: Harmony has VM and classlib functional to run Eclipse* 3.0
- May 2006: JavaOne - demonstrated functional classlib with Swing/AWT
- July 2006: First JRE Snapshot Published
- Oct 2006: Became ASF Top Level Project
- May 2007: First Milestone Build Released (M1)
- May 2007: JavaOne – “In Harmony with Eclipse” bundle CDs distributed
- …
- Dec 2007: Fourth Milestone Build Released (M4)
- Feb 2008: Fifth Milestone Build Released (M5)
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- ~2.3 million LOC
- ~1.6 million Java* code, ~ 0.7 million C/C++
- Serious testing and engineering infrastructure
- Components
- API: ~99% JDK5, ~90% JDK6
- Project VMs: DRLVM (and others)
- Tools: javac, javah, javap, jarsigner, keytool, appletviewer
- Platform Support
- Systems with x86 processors supporting Intel® SSE or greater
- Systems using processors compatible with Intel® EM64T
- Intel® Itanium®-based systems
- Operating System Support
- Several versions of Windows* and Linux
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- The Eclipse* platform was the first large application enabled on Harmony
back in ’06
- Harmony test base includes >20 Eclipse* scenarios
- Harmony performance has been tuned for Eclipse* platform
- Harmony adopted EUT for daily execution
- Harmony JVMTI has proven to work with TPTP
- Harmony adopted key TPTP JVMTI tests for daily execution
- “In Harmony with Eclipse” bundles updated regularly
- http://sourceforge.net/projects/eclipse-harmony/
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- Consider simplest workloads
- Hello World
- Startup phase of a GUI application
- Goal
- Understand detailed end to end behavior
- Find inefficiencies in class libraries for optimization
- Approach
- Disable default filters in TPTP
- Collect trace
- Analyze
- Discoveries from our first use of TPTP
- Even for small apps, data volume can be huge w/o filters
- Several TPTP usability bugs; fixes targeted for Ganymede
- Xml4profiling lacks command line tool for tsv/csv dumps
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- Collection Time Filtering
- Pro: Reduce data volume and instrumentation overhead (critical)
- Con: Data for excluded classes/method can never be seen
- Model Import Filtering
- Pro: Reduce workbench memory footprint (critical on 32bit OSes)
- Con: Can only see data that is in the model
- View Level Filtering
- Pro: Remove items from being visualized in the workbench
- Con: Does not reduce data volume or model footprint
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- Analyze more complex, long running, workload
- Snapshot performance during workload steady-state
- We use SPECjbb* 2005 workload for some of our performance tests
- Goal
- Understand application behavior
- Find inefficiencies in class libraries for optimization
- Ideal Approach
- Disable default filters in TPTP, Collect trace, Analyze
- Would prefer to collect trcxml from our batch scripts then do offline
analysis
- Discoveries from our use of TPTP
- Can’t get sufficient detail with filtering; w/o filtering; too much
data
- Pause/resume helps… But doesn’t help allow batch mode execution
- Hope for richer control with Application mode in Ganymede
- Avoid attach mode
- Instrumentation during run perturbs performance
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- So now that we’ve tried TPTP, what is next?
- Use Eclipse TPTP profiler often to improve Harmony
- Work closely with Eclipse* TPTP developers
- So they better understand how we use TPTP
- Use heap profiler
- Harmony’s memory footprint is fairly large
- Target smaller heaps (e.g., for J2SE on smaller devices)
- Already touch tested it
- Use thread profiler
- Particularly excited about optimizing multithreaded Java for multicore
platforms
- Already touch tested it
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- Features we would like to see in TPTP in future
- Better handling of huge datasets (multi-GB)
- Simpler and richer batch (scripted) collection
- Command line data reduction utility (offline analysis)
- Interface for filtering “easily” inlinable getter/setter methods at
collection time
- Features we would like to see in Harmony in future
- Fuller JVMTI implementation
- e.g., RedefineClasses - needed for TPTP dynamic attach/detach
- Better memory footprint on large Eclipse* scenarios
- Further tuned Eclipse* workbench startup time
- Java* J2SE6 support
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- Our perspective
- Apache* Harmony making great progress
- Eclipse* TPTP allows great Java* code analysis
- Both projects have opportunities for further enhancement
- Look forward to future collaboration between Harmony and TPTP
- What we would like from you
- Go try Harmony (w/ Eclipse* platform)
- Tell us about your experience (and feel free to join)
- Go try Eclipse* TPTP profiler
- Tell us about your experience (and feel free to join)
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- Intel, the Intel logo, Itanium and VTune are trademarks or registered
trademarks of Intel Corporation or its subsidiaries in the United States
and other countries.
- * Other names and brands may be claimed as the property of others.
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- A set of libraries that attach to a JVM for recording Java application's
behavior
- An extensible framework, consisting of a core runtime component
(Martini), an agent managed by the Agent Controller (JPIAgent), and a
set of data collection libraries built on top of the Martini runtime.
- Can be used to identify performance details such as classes or methods
responsible for execution bottlenecks, analyze application heap to find
memory leaks and visualize threading behavior.
- Output in the form of XML fragments (XML4Profiling)
- Can be launched from the Eclipse IDE or as a standalone program using
Java command-line options
- Applications under test can reside in Eclipse workspace, binaries on file system, or hosted in
a J2EE application server.
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- API completeness: ~99%
- Remaining 1% is in Swing as well as spread over all code
- Non conformant – Sun* is silent on TCK issue.
- Compatibility is proven by a number of free and commercial apps running
on Harmony
- VM completeness: ~100% (according to the spec)
- Interpreter, 2 JITs, DPGO
- Optimized JIT is based on StarJIT – initially tuned to show best
performance on Intel® Itanium® processors – has a good large enough set
of HLOs
- Parallel, generational GC with innovative algorithms.
- Two commercial-quality VMs are working with Harmony classlibs:
- Performance is good on server benchmarks, client still needs some
attention.
- Large set of test suites: Unit, VTS (conformance), reliability, stress,
performance, etc.
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- Configure profiling to save to a file
- Destination tab in workbench
- Configure aggregated stats with 3600 second refresh
- Avoid auto refresh… Only manual
- Start the run and immediately pause collection
- Pause button… Could not find a
way to start paused…
- Wait until steady state reached
- Resume collection
- Wait a few minutes
- Pause collection
- Wait for data to come across
- Terminate
- Restart Eclipse
- Ensures maximum memory available for file import
- Import from where you saved file in (1).
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Notes
