* Parallelize mask
We see non-negligible PP gains for long contexts.
More importantly, the strange drop in performance
observed for GPT-OSS for context >= 32k tokens is gone.
* Whith FA on, create mask as f16 directly
* WIP
* Reduce KQ mask padding to 16
Why was it 64 in the first place?
I don't observe any issues, while TG performance
for long contexts improves by 2-4%.
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Co-authored-by: Iwan Kawrakow <iwan.kawrakow@gmail.com>