On 2024-06-13 11:32 a.m., Paul Koning via cctalk wrote:
e up an entire chassis, 750-ish logic modules.
You never see a gate level delays on a spec sheet.
Our pipeline is X delays + N delays for a latch.

Gate level delays are not interesting for the machine user to know.  What is interesting 
is the detailed properties of the pipelines, including whether they can accept a new 
operation every cycle or just every N cycles (say, a multiplier that accepts operands 
every 2 cycles); how many cycles is the delay from input to output; and whether there are 
"bypass" data paths to reduce the delays from input or output conflicts.  Often 
these details are hard to pry out of the manufacturer; often they are not documented in 
the standard data sheets or processor user manuals.  But they are critical if you want to 
do work such as pipeline models to drive compiler optimizers.

But I want to know, how to compare machines if you can't compare the logic.

        paul

I never did see much in optimization at the RTL level.
You have to wait for data, regardless of fancy tricks.


Reply via email to