- gpuBandwidthSocketGroups: a single GPU whose NUMA node fails to resolve
no longer collapses the whole per-socket nvbandwidth split into one
fallback pass — it now folds into the last resolved group instead,
preserving isolation for the sockets that did resolve.
- blackbox discoverMarkedTargets: skip mounting/unmounting devices that
already have a running worker on every 2s discovery tick. This was
observed hammering the same USB target continuously (mount+unmount
every ~2s for the whole session) and contending with the worker's own
sync cycle, plausibly explaining multi-minute sync cycles seen on a
real crash bundle.
- syncFilesystem now calls syscall.Sync() directly instead of spawning
/bin/sync per copied file; blackbox mounts removable targets with
-o sync so writes are durable without relying on the app-level sync as
the primary mechanism.
- New platform.SetSyncBracketHook / satJob.syncBracket: blocks (with a
bounded timeout) on blackbox actually reaching removable media right
before and right after a diagnostic's real load step (nvbandwidth,
memtester, stress-ng, dcgmi diag, nccl, smartctl/nvme self-test...),
instead of only firing a fire-and-forget kick after the job's own log
file is written. A crash mid-load now has durable evidence the load
started, not just whatever streamed to the RAM-backed export dir before
blackbox's next scheduled cycle.
Found investigating a real support bundle where blackbox's last
successful sync (19:55:25) predated both the previous job finishing and
the crashing nvbandwidth job starting (19:56:57) — none of the crash
window ever reached durable media.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
A crash mid-command (e.g. the nvbandwidth reboot) previously lost that
job's entire output: streamExecOutput only buffered stdout/stderr in
memory and the job's log file was written once, after the process
exited. It now also streams each line straight to that file as it
arrives, so whatever printed before a crash survives.
Root filesystem here is a tmpfs overlay (toram boot), so the only real
persistence boundary is blackbox's mirror to removable media, not the
local write itself. platform.SetJobBoundaryHook lets app wire a touch
of a small kick-file after each job's output is written; blackboxWorker
now polls that file's mtime alongside its normal adaptive timer and
syncs immediately on a kick instead of waiting out the current flush
period (up to 30s).
