On 10/30/24 8:44 AM, Richard Sandiford wrote:
But the data from the BPI (spacemit k1 chip) is an in-order core.
Granted we don't have a good model of its pipeline, but it's definitely
in-order.
Damn :) (I did try to clarify what was being tested earlier, but the
response wasn't clear.)
So how representative is the DFA model being used for the BPI?
Is it more "pretty close, but maybe different in a few minor details"?
Or is it more "we're just using an existing DFA model for a different
core and hoping for the best"? Is the issue width accurate?
If we're scheduling for an in-order core without an accurate pipeline
model then that feels like the first thing to fix. Otherwise we're
in danger of GIGO.
GIGO is a risk here -- there really isn't good data on the pipeline for
that chip, especially on the FP side. I don't really have a good way to
test this on an in-order RISC-V target where there is a reasonable DFA
model.
I still see Vineet's data as compelling, even with GIGO concern.
Jeff
