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Add frame-level stack transforms to stacks - #10
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lhotari
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lhotari
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--include/--exclude decide which intervals a slice keeps, but most of every Java stack is structure that says nothing about the wait: nine Netty event-loop frames before the first application frame, and five to ten lock, park or monitor frames under the one that names the wait. stacks gains transforms that change what a kept interval's stack looks like: - --trim-root removes the longest root-side run of matching frames, --root-at starts the stack at its root-most match ([no application frame] when there is none, or unchanged with --root-at-unmatched keep), --leaf-at cuts below the leaf-most match, --collapse-leaf replaces the leaf-side wait machinery by the frame that entered it (or a category such as [lock] or [monitor] with --collapse-leaf-label category), --hide removes frames anywhere, --canonical-names removes generated-class addresses, and --thread-frame name|pool starts each line with the thread or its pool. Each REGEX option has a -from FILE form. - They apply in that fixed order after the filters, which still see the untransformed stack. Lines that transform alike merge, so no total changes, and without a transform the output is byte-identical. - Every -from option, the filters' included, takes preset:NAME, a bundled pattern list: jvm-infra, jvm-wait-machinery and jvm-idle, each with a header stating its purpose and caveats. stacks --list-presets prints them. - --collapsed-input FILE applies the same filters and transforms to any collapsed file, such as the converter's CPU view, normalising its _[j]-style markers and slashed class names; weights keep their unit. - The --summary file gains a transforms object: each option's patterns with their source, lines and weight-averaged depth before and after, and the [no application frame] weight and share. On the Pulsar broker fixtures every row of the spec's reference table is reproduced exactly, e.g. the busy off-CPU slice goes from 164 lines at a mean depth of 23.0 to 78 lines at 4.1 with --root-at and --collapse-leaf, and the CPU view from 9,839 lines at 28.9 to 4,925 at 9.6. The new testFixtureAcceptance task checks them when given -PjonoffcpuFixtures=DIR.
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Bottom of the 0.5.0 correlator stack (GitHub stack #15; spec:
stacks-transforms.md). Based onmain, which has the picocli command line from #8.What changes
stackstransforms that change a kept interval's Java stack, never which intervals are kept:--trim-root,--root-at(+--root-at-unmatched bucket|keep),--leaf-at,--collapse-leaf(+--collapse-leaf-label frame|category),--hide,--canonical-names,--thread-frame none|name|pool. Each REGEX option also has a-from FILEform.--package-names/--thread-frameas display. Filters still match the untransformed stack. Lines that transform alike merge, so totals never change. With no transform, the output is byte-identical to before.preset:jvm-infra,preset:jvm-wait-machinery,preset:jvm-idlework in every-fromoption, including--include-from/--exclude-from.stacks --list-presetsprints them with their caveat headers (e.g. musl symbolization,WorkerThread::run).--collapsed-input FILEruns any collapsed file (e.g. the converter's CPU view) through the same filters and transforms. It strips_[j]/_[i]/_[0]/_[1]markers and turns slashed class names into dotted ones. Weights keep their unit. Options that need profile data are refused.--summarygains atransformsobject: patterns with their sources,linesBefore/linesAfter,framesBefore/framesAfter, and thenoApplicationFrameweight and share.testFixtureAcceptance -PjonoffcpuFixtures=DIR. The fixtures are recordings kept outside the repo, so the task is skipped without the property.Verification
./gradlew spotlessCheck :jonoffcpu-correlator:check -PjonoffcpuFixtures=…/jonoffcpu-plans/fixturespasses.--collapsed-inputand off-CPU busy slice via--exclude-from preset:jvm-idle --exclude <bookkeeper take>:--hide preset:jvm-infra--trim-root preset:jvm-infra--collapse-leaf preset:jvm-wait-machinery--root-at '^org\.apache\.'StackTransformsTestcovers the spec's unit cases: merging with intervals and nanos added,--excludeseeing trimmed frames, the[no application frame]bucket, canonical names, pool frames, category labels, collapsed-input normalisation, presets and totals under every transform combined.Spec deviations to note
A;B;C;x.App.m;Dwith--trim-root '^(A|C)$'→ unchanged" contradicts its own rule.Amatches, so the root-side run[A]is trimmed, givingB;C;x.App.m;D. The implementation follows the rule, which is also what reproduces the reference table; the test documents both cases.--collapse-leaf-label categorykeeps the entry frame itself when no category applies (e.g.CompletableFuture$Signaller.block); the spec lists no category for that case.