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Diffstat (limited to 'tools/guest-diag/wall2')
| -rw-r--r-- | tools/guest-diag/wall2/README-session77.md | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/tools/guest-diag/wall2/README-session77.md b/tools/guest-diag/wall2/README-session77.md index 92f3bc3..92d2986 100644 --- a/tools/guest-diag/wall2/README-session77.md +++ b/tools/guest-diag/wall2/README-session77.md @@ -833,3 +833,20 @@ every ~0.2 s in a loop around the burst (or perf trace -s during a burst); the auth-tag sema value (advance past nextPut) via the RAM file; (c) the loop timeout (gpuCheckTimeout) may eventually error the client - the write must land first. + +**29. Session 102: fd-sampler miss, no nvidia debugfs; the memdesc hunt narrows.** +The 0.15 s /proc/1549/fd sampler over 20 s caught NO transient path (the +open/read(299)/close reader is bursty or dormant between bursts; the static +fds are /dev/nvidiactl, /dev/nvidia0, /dev/nvidia-modeset, a socket, the +GLCache .toc/.bin pair, and a memfd "allocation fd"). No nvidia debugfs +tree exists in the guest. Remaining ranked paths to the auth-tag sema +(memdesc + finishPayloadOffset + 4): (1) content-locate the scrubber's +channel buffer by its method stream (the C5B5/C56F shapes: SET_OBJECT +0xc5c0/0xc5b5, headers 0x200121ed/0x200120a9 observed in the session-78 +window dumps) and read/write the sema inside; (2) the scrubber channel's +own sema-push decodes (its pushes carry the auth-tag VA = pbGpuVA + +authTagBufSemaOffset; grep the boot's sema-pushall for the scrubber +channel id and read the rel= VA - then PDB-walk it); (3) sample the fd +burst narrower (0.02 s) right after a client restart when the burst is +hot. The service-side ideal: on detecting the scrubber channel, resolve +its channel buffer and pre-advance the auth-tag sema (a durable fold). |