th#1043: forced group-fit fp8 survives the bf16-resident upcast (0.48.1)#375
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Live 0.48.0 pod showed the joint fp8 forcing being silently un-done by load_from_pretrained's single-lane resident-upcast check (gw#534 rung 2): the first lane fit current free VRAM alone, upgraded back to bf16, and re-starved its sibling into the refused offload placement. A forced storage dtype now disables the local upgrade — the headroom belongs to the group, not the first lane to load.
PaulFidika
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Jul 23, 2026
….1) (#375) Live 0.48.0 pod showed the joint fp8 forcing being silently un-done by load_from_pretrained's single-lane resident-upcast check (gw#534 rung 2): the first lane fit current free VRAM alone, upgraded back to bf16, and re-starved its sibling into the refused offload placement. A forced storage dtype now disables the local upgrade — the headroom belongs to the group, not the first lane to load.
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Summary
load_from_pretrained's gw#534 bf16-resident upcast check evaluates a SINGLE lane against current free VRAM, saw the first lane fit alone, and upgraded it back to full bf16 residency (in_vram 43.2GB) — re-starving the sibling lane into the offload placement the shared-component invariant refuses.force_storage_dtype(the joint group decision) now passesallow_bf16_resident_upgrade=False— a forced fp8 lane never locally upgrades; the headroom belongs to the group.Test plan
bf16_resident_fitsreturning True, an unforced fp8 load still upgrades (gw#534 preserved) while a forced one keeps fp8 hooks armed (real tiny diffusers pipeline, CPU)