google / google/CFU-Playground
hps_accel on PLATFORM=hps fMax is low
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Description
fMax for builds of hps_acccel on hps is quite low.
commit 3302c0 ([link](https://github.com/google/CFU-Playground/pull/251/commits/3302c04971850566c5c8a588ed6a973d356ab2d8)) sets the clock divisor to 12, making the clock speed about 37.5MHz, and the toolchain often report fMax in high 40MHz range.
We'd like to understand what keeps fMax low, and develop a plan to increase it.
Ideas:
* what is fMax of Full VexRiscV config (i.e most common build) vs SlimPerf+Cfu
* is this a misconfiguration?
* is it due to the fix for CFU instruction in branch delay slot?
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