perf(dflash): compiled create_block_mask / flex_attention wrappers [3/3] - #936
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…led wrappers create_dflash_block_mask now goes through SpecForge's compile_friendly_create_block_mask (which forwards BLOCK_SIZE via **kwargs), and DFlash attention uses SpecForge's compile_friendly_flex_attention instead of the transformers copy. The compiled wrapper is imported lazily inside create_dflash_block_mask: importing it at module scope pulls in torch._dynamo, and tests that build stubs under patch.dict(sys.modules) then purge it and hit a duplicate TORCH_LIBRARY registration on re-import (test_dflash_losses run alone). Note: importing specforge.modeling.draft.flex_attention sets torch._dynamo.config.recompile_limit = 64 process-wide. Split out of #905. Co-authored-by: Inhyuk Cho <ihcho@lgresearch.ai> Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
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Split of #905, part 3 of 3. Stacked on #935. Draft until a GPU throughput A/B is in.
Changes
create_dflash_block_maskuses SpecForge'scompile_friendly_create_block_mask(now forwarding**kwargs, soBLOCK_SIZEstill works).compile_friendly_flex_attentioninstead of the transformers copy. On torch ≥ 2.7 both are plaintorch.compile(flex_attention).create_dflash_block_mask. In Fix DFlash attention masking #905, the module-level import pulledtorch._dynamoin undertest_dflash_losses'spatch.dict(sys.modules). That made the file fail 28/28 when run alone (reproduced on Fix DFlash attention masking #905's head7ccc036), which CI's single discover run hides. With this PR it passes 28/28 alone.Open questions
S,N) change every step. On CPU,test_dflash_mask.pygoes from 0.1s to 17s because each new shape compiles. GPU training needs a samples/s comparison against feat(dflash): share DFlash masks with inference, default masks for spec_generate [2/3] #935, for example a 200-step Qwen3.8 DFlash2 flex run.specforge.modeling.draft.flex_attentionsetstorch._dynamo.config.recompile_limit = 64for the whole process. It is now imported by every DFlash user, not only Eagle3/PEagle.Co-authored-by @cih9088 (original #905); every commit carries a
Co-authored-by: Inhyuk Chotrailer.🤖 Generated with Claude Code