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What does this PR do ?

Explicitly zeroes out padding token activations for dynamic inference. This is necessary to ensure that padding tokens do not influence quantization scaling factors.

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@santhnm2 santhnm2 requested review from a team as code owners October 28, 2025 20:38
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copy-pr-bot bot commented Oct 28, 2025

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@santhnm2 santhnm2 self-assigned this Oct 28, 2025
Signed-off-by: Keshav Santhanam <[email protected]>
Signed-off-by: Keshav Santhanam <[email protected]>
@santhnm2 santhnm2 requested a review from a team as a code owner November 3, 2025 23:06
Signed-off-by: Keshav Santhanam <[email protected]>
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"generated_text": " And that this is the place where you can be yourself, and be yourself in the most beautiful way possible. And that this is the place where you",
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Why is this changing?

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Sorry missed this, the outputs were previously incorrect due to the influence from the padding tokens.

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Seems ok to me, but why are we padding out outputs in three specific places (decoder_input in GPTModel and MambaModel, and core_attn_out in Attention)?

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santhnm2 commented Nov 4, 2025

Seems ok to me, but why are we padding out outputs in three specific places (decoder_input in GPTModel and MambaModel, and core_attn_out in Attention)?

These are the places where the hidden states for padding tokens enter as zero but exit as nonzero. This is problematic because these non-zero padding values can corrupt amax calculations.

Signed-off-by: Keshav Santhanam <[email protected]>
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/ok to test 39794d9

@ko3n1g ko3n1g added this to the Core 0.16 milestone Nov 10, 2025
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Discussed over Slack, LGTM, thanks!

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6 participants