Per-task engine state, downloaded/effective_segments, every segment's own
state, and the engine's SegmentBudget snapshot -- printed once, when a task
times out, instead of needing to re-run the bench under a debugger or add
throwaway instrumentation to find out why. This is what actually diagnosed
the SegmentBudget over-admission bug fixed in the previous commit: the dump
showed budget.active pinned at max_active_segments while multiple tasks sat
starved, which is what pointed straight at confirm_slot()'s missing
engine-wide check rather than a per-task target bug.
Also updates the vdm_bench_load20 ctest registration's comment: the
straggler under --preset tsan that motivated running it at reduced
concurrency (docs/adr/0016's postscript) is now suspected to have been the
same SegmentBudget bug (docs/adr/0017), not the TSan-timing artifact first
guessed -- not reverified at the DoD's full shape under TSan in this change,
so the reduced-concurrency registration stays for now.
Co-Authored-By: Claude Sonnet 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01Q3QrF7rCt21bkAjt9BCDFQ
For the M7 RSS gap (core/docs/m7-baseline.md: ~70 MB measured vs ADR 0012's
~45-50 MB estimate) -- "find where before tuning anything". No root here to
install massif or heaptrack, so this is a small in-process equivalent:
operator new/delete (already overridden for alloc-check's counter) now also
track, per call site (one return address via __builtin_return_address(0),
cheap enough to run for a whole scenario), live (not-yet-freed) bytes. Runs
the same 20-task concurrent scenario as `load`, waits for peak RSS to stop
growing, then prints the top sites by live bytes -- resolved via one batched
addr2line invocation against /proc/self/exe (dladdr alone only resolves
dynamic-symbol-table entries, which misses most of this codebase's
internal-linkage call sites), with dladdr as a per-site fallback.
Also adds the nothrow operator new/delete overloads alongside the existing
plain ones: without them, anything that allocates via the nothrow form (e.g.
std::stable_sort's std::get_temporary_buffer, hit once while investigating
the RSS gap) falls through to ASan's own default nothrow new while still
being freed through this file's plain delete override -- an
alloc-dealloc-mismatch ASan correctly flags as a real ABI-level bug in an
allocator override that claims to intercept "everything".
Using this tool, sum(effective_segments) across all 20 tasks vs.
Engine::segment_budget().budget() (now cross-checked and printed together)
showed the budget hands out well more than max_active_segments -- the actual
root cause, in core/src/segment/budget.cpp, not covered by this commit.
Co-Authored-By: Claude Sonnet 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01Q3QrF7rCt21bkAjt9BCDFQ
Three subcommands in one binary, driving vdm::Engine directly (docs/04 §8):
- throughput: a single download against a fast local origin
(support/local_server.hpp, busybox httpd), reporting Mbps/CPU%/RSS. Gates
on --require-mbps/--max-cpu-pct only when passed, so the ctest smoke
registration stays a correctness check, not a hardware-dependent
perf gate -- the real 1-Gbit-link sign-off is a manual/CI job (see the
file's header comment).
- load: N concurrent tasks against tools/testserver's `throttled` mode
(support/testserver_client.hpp), reporting peak RSS via getrusage(). Paced
externally rather than through the engine's own rate::RateLimiter or
busybox: the limiter's pause/resume path allocates on every throttle event
(would contaminate alloc-check's measurement) and under heavy segment
contention was found to starve individual tasks indefinitely (see
docs/adr/0016, added here); busybox couldn't sustain the DoD's ~160
concurrent connections (20 tasks * default_segments=8) reliably. The
ctest registration runs at reduced concurrency under sanitizer presets --
see the CMakeLists.txt comment and the ADR's postscript.
- alloc-check: operator new/delete overridden process-wide, sampling the
allocation count across a steady mid-transfer window against a paced
tools/testserver origin. Caught a real bug in the same change (see the
http_client.cpp commit) and, by dropping its Engine mid-download to end
cleanly, also surfaced the quiesce() use-after-free (see that commit).
core/docs/m7-baseline.md records actual measured numbers against the M1/M7
DoD lines, including where they don't clear yet (RSS ~70 MB vs a 60 MB
target; throughput/CPU only measured on loopback, no 1 Gbit link available
here) rather than rounding them away.
docs/adr/0016 documents a rate::RateLimiter fairness gap found building the
load subcommand: a single shared TokenBucket under heavy segment contention
has no fairness ordering across its peek/commit race and can starve a
waiter well past what its configured rate implies. Filed as a follow-up
(it's a core/src/rate design question, not a tools/bench one) rather than
fixed here, along with a related TSan-only load-test straggler that could
not be root-caused in this environment.
Co-Authored-By: Claude Sonnet 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01Q3QrF7rCt21bkAjt9BCDFQ
Lays out Velox Download Manager (IDM-class download manager for Ubuntu
26.04) as a monorepo ready for parallel lane development. No implementation
code by design.
- docs/: architecture, roadmap M0-M7, IDM-parity GUI spec, engine design,
Firefox extension spec, risks/spikes, packaging
- contracts/: wire-contract skeleton (JSON Schema + fixture templates) —
the single synchronization point between lanes
- docs/agents/: one brief per lane (PROTO, CORE, DAEMON, GUI, EXT, PKG/QA)
with owned directories, build order and definition of done
- CLAUDE.md: rules of engagement — lane ownership, layering, non-negotiables
- CMake scaffolding with dev/tsan/release/ci presets
Two environment findings shape the design: Firefox here is the Mozilla snap
(native-messaging risk, so the extension carries a loopback-WebSocket
fallback), and Wayland forbids passive clipboard monitoring (so clipboard
capture is explicit-action-first).
Co-Authored-By: Claude Opus 5 <[email protected]>
samiandClaude Sonnet 5