AlxcBTW 2a15be09c9 perf(agc): pre-sync the DCC key writers of a dispatch's images before the GPU mutex ...

The stage-A pre-sync of a dispatch listed only the surfaces that stage B reads on the CPU. The DCC
keys of an image that a recorded kernel writes were not in the list, so stage B waited for that
kernel in WaitForKeyWriters with the GPU mutex held and every other worker queued behind the wait.
At the Minecraft Dungeons II title the pre-sync fired once in 296,000 dispatch checks while
WaitForKeyWriters synchronized 400 times per 10 s.

PresyncSurfaces now also returns the key range of every image binding (PresyncSurface::dccKeys).
presync waits for a key range only while recorded work writes it, the key-store memo does not
already give its value (DccKeyWritersPending) and, under the mutex it takes for a moment anyway, the
pending stores do not give the keys either (DccKeyWriterNeedsSync, the test WaitForKeyWriters makes
before it synchronizes). Which keys the dispatch reads, and when, is unchanged: the locked lookup runs
as before and finds nothing pending.

APS5_NO_DCC_PRESYNC=1 leaves the key ranges out. The [presync] line counts key ranges checked,
pre-syncs that only the keys required and the outcomes of WaitForKeyWriters. The test
agc_driver_dcc_key_presync covers a kernel that writes the keys, a recorded fill of the keys and
nothing pending, and skips with the reasons check_skips.py expects when the device has no timeline
semaphores or no host import.

2026-10-16 14:18:46 +02:00

..

dev

perf(agc): pre-sync the DCC key writers of a dispatch's images before the GPU mutex

2026-10-16 14:18:46 +02:00

user

fix(agc): record nothing in the pipeline journal without its file lock

2026-10-16 12:52:28 +02:00