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Paul Hontz
db44dba833
SteamOS keeps kernel tracing on for its GPU performance captures (gpu-trace.service), and its Mesa, built with gpuvis, then writes a marker into the trace buffer for each traced driver function. On the Steam Frame that is some 480,000 writes a second: the driver's thread spent its time in them, and the game ran at about 50 frames a second instead of the headset's 72 (#71 has the same for the arm64 build). The Steam Deck runs the same gpu-trace service and the same Mesa, so it needs this too. The executable now defines open() and openat() (and their 64-bit names), exported so that the driver's calls reach them: they refuse trace_marker and pass everything else on. gpuvis then skips its markers. HALO_GPU_TRACE_MARKERS=1 lets the driver write them, to capture with gpuvis. The link takes libdl for dlsym, which glibc before 2.34 keeps there.