Ahmed Ghazy
07/24/2020, 11:01 AMFP_CORE_UTIL
.
The process of finding the best configuration parameters for a design is systematic that we have it automated (what we call an exploration); please check this for more information on that. You may be interested in seeing the effects of the PL_TARGET_DENSITY
and SYNTH_STRATEGY
parameters, on which you can read here.Matt Venn
07/24/2020, 11:08 AMPL_TARGET_DENSITY?
Ahmed Ghazy
07/24/2020, 11:34 AMFP_CORE_UTIL
) is used during floorplanning and determines the die area; in case of a logic block, it's basically equal to the (total area of logic cells)/(die area)
The target placement density (PL_TARGET_DENSITY
), which varies from 0.0
to 1.0
is used during global placement. Intuitively*, it's a measure of how close the cells are placed to each other, low values meaning further from one another, higher values meaning closer. 0.3
-0.4
is usually a good range to keep cells far enough and allow diode insertion.
* The exact equation would be more complex to explain as the placer models cells as electric charges uses the electrostatic equation (here is the paper if you're interested tho!).Matt Venn
07/24/2020, 11:39 AMAhmed Ghazy
07/24/2020, 11:53 AMspm
design with very low utilization vs. high utilization:Matt Venn
07/24/2020, 12:14 PMAhmed Ghazy
07/24/2020, 12:35 PM