The owner's CPU/GPU split, "both, parts first". With JIHAD_GPU_CPU_PARTS=1 every GPU frame is
composed without the page's fixed and sticky parts (engine 0070, flag 128) and the daemon draws
them over it from a picture of the parts alone (flags 64|128, remade when the parts' generation
moves); what lay beneath the parts is kept per slot so frames still build on each other. Both
lanes make frames of the same kind (the main lane's are dressed at its poll, under the frame lock).
Faults found and fixed on the way (docs/rounds/t505-2026-10-26/notes.txt):
- the picture never matched a frame (the engine's keep split; engine 0070 reports whole layer
rects); three misses in a row now turn the parts back to the engine's for the document;
- frames built on their slot's own frame had no scroll compensation in the diff (engine 0071):
every layer transaction during a pan was a whole read;
- T-511's own-slot rule took a slot stale whole after a one-off whole change (each drag's
settle): never a slot stale whole now (both lanes' default behaviour);
- the picture's geometry no longer has to match the frame's overscan row or height; it reads only
the rows around the last picture's parts.
JIHAD_GPU_CPU_PARTS_STALE=1 (the owner's trade, off): frames keep the previous picture while a
changed part's is made (at most 600 ms).
Scripted pan, the card moving: desktop Wikipedia 9.4 fps without, 11.2 with the parts on the
CPU, 14.2 with the stale switch too; the long page 18.8 -> 24.7 (parts + stale). By finger the
rounds spread 11-13 fps on Wikipedia against ~10 without. Frames looked at: parts once, in place.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01XtfxSpM1w2uiVKeLKoV3g3
NotAlexNoyleandClaude Opus 5.5
2bd3e6f1ae
