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authorArthur Hanson Rasmusson <arthur@vgpu.io>2026-10-25 05:57:04 -0400
committerArthur Hanson Rasmusson <arthur@vgpu.io>2026-10-25 05:57:04 -0400
commit9813c9b9b6d9fa7e56fe0e77ccd4589fd9e90902 (patch)
tree5d9afb11ec6e5a08c88bb741f1f0e07b36686a1e /tools/guest-diag/wall2/gdbfill.gdb
parent45978e9202412fb9fc6088718e9720f22ece7b30 (diff)
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wall-2 session 74: the client's 11s stalls are userspace completion-slot spins; the next wall is the polled RM control 0x2080a097
Root-caused the vk_frame client's exact 11.00s gaps: a pure sched_yield + clock_gettime userspace spin inside libnvidia-eglcore's EGL/GL init, waiting for completion slots (u16 at slot+0xe == 0xffff) in /dev/nvidiactl mappings. Guest-side filling of the slot flags lets the client proceed immediately, but vkCreateDevice still fails -4: with the slots filled the client settles into an NVOS54 poll of RM control 0x2080a097 (paramsSize=1168) which our emulation answers with the generic all-zero reply, so the poll never completes. Also captured: sema_push_raw dumps proving the GR channel-init push contains NO release (entry0 decodes 2 methods then zeros; entry2 SET_OBJECT 0xc597 then zeros), and the negative result that neither channelFillGpFifo nor nvWriteGpEntry runs for this channel's kick. New probes: gdbpoll6/gdbu16/gdbfill/gdbwatch/gdbparam/gdbgap3/gdbspin (slot check, flag fill, NVOS54 param dump, backtraces), slotfill{,2}.sh (guest slot watcher), stracevk/fastrun{,2}.sh (strace+perf recipes), find_ring_va.py and vmap_watch2.py (vmap/kcore watchers), README-session74.md.
Diffstat (limited to 'tools/guest-diag/wall2/gdbfill.gdb')
-rw-r--r--tools/guest-diag/wall2/gdbfill.gdb13
1 files changed, 13 insertions, 0 deletions
diff --git a/tools/guest-diag/wall2/gdbfill.gdb b/tools/guest-diag/wall2/gdbfill.gdb
new file mode 100644
index 0000000..41d1ea3
--- /dev/null
+++ b/tools/guest-diag/wall2/gdbfill.gdb
@@ -0,0 +1,13 @@
+set pagination off
+set confirm off
+break *POLLADDR
+commands 1
+silent
+set $e = *(unsigned long*)($rdi+0x1428)
+if *(unsigned short*)($e+0x2e) == 0xffff
+ set {unsigned short}($e+0x2e) = 0
+ printf "FILLED slot at %p+0x2e -> 0\n", $e
+end
+continue
+end
+continue