13 Jun
2024
13 Jun
'24
4:31 p.m.
On 2024-06-13 11:32 a.m., Paul Koning via cctalk wrote:
e up an entire chassis, 750-ish logic modules.
But I want to know, how to compare machines if you can't compare the logic.
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. paul
I never did see much in optimization at the RTL level.
You have to wait for data, regardless of fancy tricks.