Fixes to alternating SWA layers in Gemma2 #31775
Merged
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What does this PR do?
Reverses the order of global and sliding attention layers in Gemma2. This brings it in line with Google's implementation in which sliding attention is used on layers 0, 2, 4.., whereas currently the Transformers implementation uses sliding attn on layers 1, 3, 5...
Changes
HybridCache.update
to read thesliding_window
argument fromcache_kwargs
since it wasn't being parsed otherwise. The cache was created with alternating max seq lenghts of 4k and 8k, but all layers were being updated as if they were 8k, causing out-of-bounds errors and CUDA exceptions.Before submitting
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Who can review?
Anyone in the community is free to review the PR once the tests have passed. Feel free to tag
members/contributors who may be interested in your PR. @ArthurZucker