[Performance][torch.compile]: Inductor partition performance issues

[ProExpertProg]

Performance issues

As seen in #27080, Inductor partition is not always faster than Dynamo partition or no partition. Those are two separate issues:

• On Blackwell, no partition is sometimes faster than Inductor partition (particularly TTFT with attention+quant fusion). This might just be attributable to the difference in performance between FULL_AND_PIECEWISE and FULL_DECODE_ONLY cudagraph modes.
• On Hopper, Inductor partition seems to outperform Dynamo partition, although we only have numbers for TP=4. We should try again with llama-8B TP=1.

cc @zou3519 @BoyuanFeng

[BoyuanFeng]

yes let me check