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
coz on cjson — integration status
coz is wired into the harness (SPEC §12): targets/cjson/harness.c
carries a -DHOTPATH_COZ throughput progress point, and
scripts/coz-profile.sh + just coz cjson build the instrumented binary
and run coz run. scripts/coz-summary.py ranks lines by causal
throughput effect.
Runtime limitation in this container: the distro coz-profiler
(apt) aborts inside its own init_coz during startup —
pthread_create interposition recurses ("init_coz in progress, do not
recurse" → SIGABRT) before main runs. This is a known coz/glibc
incompatibility on newer glibc, independent of the harness. It reproduces
on the pristine binary with a bare coz run, so it is not our
instrumentation.
What we use instead: callgrind --cache-sim --branch-sim
(results/cjson/hotspots.txt) is the working profiler and gives an
unambiguous class-selection signal for cjson — glibc float
serialization/parsing (__printf_fp, strtod) plus cJSON
parse_value/print_value dominate. The coz path is ready for an
environment with a compatible coz runtime (bench-metal / a pinned coz
build); no code change is needed there.