open-iov.git/tools/guest-diag/guest_pmap_win.py, branch gr-forwarding

guest-diag: cheaper trace read, optional push sampler, bigger pagemap batches

2026-09-29T18:47:17+00:00

Under load the semfix poll grepped the whole (growing) trace file and the track_waits push block spawned three guest processes per sample, both of which slowed the pin path into the client's failure window. The trace read now tails 128 KB; track_waits.sh gates the push dump behind PUSH=0; the pagemap helper reads 32 KB chunks.

kernel: grace window for untranslatable GR entries; tools: coalesce window pin output

2026-09-29T18:41:14+00:00

The first GR window pin landed ~2 s after the pump consumed the freshly created channels' GPFIFO entries on the first failed read, so the pushes (and the tracking-semaphore releases they carry) were lost. GR entries with an unresolvable push page now stay pending for sema_gr_grace_ms (default 8 s) before the stale-entry consume; a pin landing in that window makes the entry readable and it executes normally. The completion counter is still published from put at the end of every pass, so the client's counter wait is not delayed. guest_pmap_win.py coalesces contiguous VA+PA pages into run lines, so a 15k-page window transfers as ~200 lines instead of ~15k and the pin batch lands within a second of the pages appearing.

tools: pin GR push-buffer window from guest pagemap per boot; widen injected-pin table

2026-09-29T18:38:44+00:00

The GR channel GPFIFO entries point at pushes in the client GPU VA window (observed 0x200400000 + stride, one allocation per channel) and the pump cannot read them: pushes_nomap grows and the tracking-semaphore releases they carry never land. The pushes are sysmem pages mapped into the client process, so /proc//pagemap in the guest gives the GPA. New guest helper guest_pmap_win.py batch-reads the pagemap of a VA range (512 entries per pread). New host tool pin_gr_window.py rescans the window on an interval, follows cdt pid changes, and injects VA->PA runs through sema_map_add (same mechanism as the counters and the CE pushbuffer pins). The injected-pin table grows 8k -> 32k slots so the CE pushbuffer (4096) plus the GR window pages fit without drops.