#134 baseline with ZGC, sample retry on gc, gc hint options#143
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jamesmarkchan merged 21 commits intodevfrom Mar 2, 2026
Merged
#134 baseline with ZGC, sample retry on gc, gc hint options#143jamesmarkchan merged 21 commits intodevfrom
jamesmarkchan merged 21 commits intodevfrom
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- Add GcDetector.java: detects JVM GC events via GarbageCollectorMXBean notifications - Modify BenchmarkRunner: retry sample up to MAX_GC_RETRIES (3) when GC detected - Add gcRetryEnabled option to App, BenchmarkConfig, and RunBenchmarkCommand (--gc-retry) - Set run.jvmargs=-XX:+UseZGC in project.properties to enable Generational ZGC Co-authored-by: jamesmarkchan <6020424+jamesmarkchan@users.noreply.github.com>
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[WIP] Implement solution for issue #134 on gen zgc configuration
Implement Generational ZGC configuration and GC-aware sample retry (#134)
Feb 26, 2026
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Pull request overview
This PR aims to reduce benchmark noise caused by GC pauses by (1) running with ZGC by default in project/packaging configs and (2) adding an opt-in mechanism to detect GC during a sample and retry that sample.
Changes:
- Added a
GcDetectorthat listens for GC JMX notifications, plus atriggerAndWait()helper for GC “hinting”. - Added per-sample GC-detection retry logic to
BenchmarkRunnerbehind a newgcRetryEnabledflag (wired through CLI + GUI + persisted config). - Updated run/packaging configs (NetBeans, Ant/jpackage, Debian wrapper) to pass
-XX:+UseZGC; added a GitHub Actions DEB build workflow.
Reviewed changes
Copilot reviewed 11 out of 11 changed files in this pull request and generated 3 comments.
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| File | Description |
|---|---|
src/jdiskmark/RunBenchmarkCommand.java |
Adds --gc-retry / -g CLI flag and persists it into App.gcRetryEnabled. |
src/jdiskmark/MainFrame.java |
Adds GUI menu toggles for GC hints and GC retry, persisted via App.saveConfig(). |
src/jdiskmark/MainFrame.form |
NetBeans form updates for the new menu items. |
src/jdiskmark/GcDetector.java |
New class to detect GC events + provide GC hinting helper (triggerAndWait()). |
src/jdiskmark/BenchmarkRunner.java |
Adds GC-aware retry loop and optional GC hinting calls around benchmark phases. |
src/jdiskmark/BenchmarkConfig.java |
Adds gcRetryEnabled and gcHintsEnabled to the benchmark config snapshot. |
src/jdiskmark/App.java |
Adds persisted config keys for GC retry/hints, and injects them into BenchmarkConfig. |
pkg/ubuntu/symlink/postinst |
Enhances DEB post-install to create a desktop entry and update desktop database. |
nbproject/project.properties |
Sets NetBeans run JVM args to -XX:+UseZGC. |
build.xml |
Adds --java-options for jpackage/DEB launcher and sets a default jvm.run.options=-XX:+UseZGC. |
.github/workflows/linux-build.yml |
New workflow to build/upload DEB artifacts using Ant on Ubuntu. |
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Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
) - Default gcRetryEnabled to false (was incorrectly true) - Compensate progress counters on GC retry: subtract config.numBlocks from writeUnitsComplete/readUnitsComplete before each retry to cancel block-level increments from the failed attempt - Fix getGlobalGcCount() to count all GC collectors when no ZGC "Cycles" beans are present, avoiding 2s timeout on G1/Parallel GC Co-authored-by: jamesmarkchan <6020424+jamesmarkchan@users.noreply.github.com>
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Pull request overview
Copilot reviewed 12 out of 12 changed files in this pull request and generated 4 comments.
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Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
…configure-gen-zgc-sample
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GcDetector.java- utility class to detect GC events viaGarbageCollectorMXBeannotificationsBenchmarkRunner.java- add GC detection and sample retry logic (up to MAX_GC_RETRIES=3)App.java-gcRetryEnableddefaults tofalse(opt-in, not opt-out)BenchmarkConfig.java- addgcRetryEnabledfield (primitiveboolean)nbproject/project.properties- setrun.jvmargs=-XX:+UseZGCto enable Generational ZGC--gc-retryCLI option toRunBenchmarkCommand.javaGcDetector.getGlobalGcCount()to work with all GC collectors (not just ZGC "Cycles" beans)💡 You can make Copilot smarter by setting up custom instructions, customizing its development environment and configuring Model Context Protocol (MCP) servers. Learn more Copilot coding agent tips in the docs.