[Spec] Support mamba-radix-cache-strategy extra_buffer_lazy with DFLASH (#34763)

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>
This commit is contained in:
gilfordting
2026-08-15 16:36:59 -07:00
committed by GitHub
co-authored by Claude Fable 5
parent 3802a725ac
commit 4a6dc267e1
4 changed files with 146 additions and 8 deletions
@@ -1996,7 +1996,7 @@ Please consult the documentation below and [server_args.py](https://github.com/s
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<td style={{padding: "9px 12px", fontWeight: 500, backgroundColor: "rgba(255,255,255,0.02)"}}>`--mamba-radix-cache-strategy`</td>
<td style={{padding: "9px 12px", backgroundColor: "rgba(255,255,255,0.05)"}}>The strategy to use for mamba scheduler. <code>auto</code> currently defaults to <code>no_buffer</code>. 1. <code>no_buffer</code> does not support overlap scheduler due to not allocating extra mamba state buffers. Branching point caching support is feasible but not implemented. 2. <code>extra_buffer</code> supports overlap schedule by allocating extra mamba state buffers to track mamba state for caching (mamba state usage per running req becomes <code>2x</code> for non-spec; <code>1+(1/(2+speculative_num_draft_tokens))x</code> for spec dec (e.g. 1.16x if speculative_num_draft_tokens==4)). 2a. <code>extra_buffer</code> is strictly better for non-KV-cache-bound cases; for KV-cache-bound cases, the tradeoff depends on whether enabling overlap outweighs reduced max running requests. 2b. mamba caching at radix cache branching point is strictly better than non-branch but requires kernel support, currently only extra_buffer supports branching.</td>
<td style={{padding: "9px 12px", backgroundColor: "rgba(255,255,255,0.05)"}}>The strategy to use for mamba scheduler. <code>auto</code> currently defaults to <code>no_buffer</code>. 1. <code>no_buffer</code> does not support overlap scheduler due to not allocating extra mamba state buffers. Branching point caching support is feasible but not implemented. 2. <code>extra_buffer</code> supports overlap schedule by allocating extra mamba state buffers to track mamba state for caching (mamba state usage per running req becomes <code>2x</code> for non-spec; <code>1+(1/(2+speculative_num_draft_tokens))x</code> for spec dec (e.g. 1.16x if speculative_num_draft_tokens==4)). 2a. <code>extra_buffer</code> is strictly better for non-KV-cache-bound cases; for KV-cache-bound cases, the tradeoff depends on whether enabling overlap outweighs reduced max running requests. 2b. mamba caching at radix cache branching point is strictly better than non-branch but requires kernel support, currently only extra_buffer supports branching. 3. <code>extra_buffer_lazy</code> lowers <code>extra_buffer</code>&apos;s slot cost by allocating one track slot per request instead of two; the second slot is allocated on demand at track-interval boundaries (for speculative decoding it is reserved ahead of each verify window and committed only for accepted boundary crossings). Compatible with speculative decoding (EAGLE/NGRAM/DSPARK/DFLASH); not supported under PD disaggregation.</td>
<td style={{padding: "9px 12px", backgroundColor: "rgba(255,255,255,0.02)"}}>`auto`</td>
<td style={{padding: "9px 12px", backgroundColor: "rgba(255,255,255,0.05)"}}><code>auto</code>, <code>no_buffer</code>, <code>extra_buffer</code>, <code>extra_buffer_lazy</code></td>
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