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Claude
832dab3445
- coz wired (harness -DHOTPATH_COZ hook, scripts, just coz) + installed,
but the apt coz runtime aborts in its own init_coz/pthread_create
interposition on this glibc (known coz bug, reproduces on the pristine
binary). Documented in results/cjson/coz/README.md; callgrind cache-sim
is the working profiler.
- cjson no-op verdict smoke: full C pipeline flows (clang {out} baseline
rebuild, Unity/CTest + golden gates, interleaved bench) to a correct
null result (median 0.9995).
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EcKPWQ3MQD4NdEHwar96u2
24 lines
1.1 KiB
Markdown
24 lines
1.1 KiB
Markdown
# coz on cjson — integration status
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coz is **wired** into the harness (SPEC §12): `targets/cjson/harness.c`
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carries a `-DHOTPATH_COZ` throughput progress point, and
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`scripts/coz-profile.sh` + `just coz cjson` build the instrumented binary
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and run `coz run`. `scripts/coz-summary.py` ranks lines by causal
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throughput effect.
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**Runtime limitation in this container:** the distro `coz-profiler`
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(apt) aborts inside its own `init_coz` during startup —
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`pthread_create` interposition recurses ("init_coz in progress, do not
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recurse" → SIGABRT) before `main` runs. This is a known coz/glibc
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incompatibility on newer glibc, independent of the harness. It reproduces
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on the pristine binary with a bare `coz run`, so it is not our
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instrumentation.
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**What we use instead:** callgrind `--cache-sim --branch-sim`
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(`results/cjson/hotspots.txt`) is the working profiler and gives an
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unambiguous class-selection signal for cjson — glibc float
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serialization/parsing (`__printf_fp`, `strtod`) plus cJSON
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`parse_value`/`print_value` dominate. The coz path is ready for an
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environment with a compatible coz runtime (bench-metal / a pinned coz
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build); no code change is needed there.
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