14. Metrics

The SiliconCompiler schema includes a ['metric', ...] dictionary with a large number of parameters to be tracked on a per step and per index basis.

The metric values are used in the minimum() and maximum() functions to select the best compilation based on the associated ['flowgraph', <flow>, <step>, <index>, 'goal', ...] and ['flowgraph', <flow>, <step>, <index>, 'weight', ...] set for the step and index within the flowgraph. For a complete description of the minimum() function, see the Core API section of the reference manual.

The default ‘asicflow’ demonstrates a traditional ASIC optimization function, with hard requirements set up for hold, setup, warnings, and errors and soft requirements for area and power.

if metric in ('errors','warnings','drvs','holdwns','setupwns','holdtns','setuptns'):
    chip.set('flowgraph', flow, step, index, 'weight', metric, 1.0)
    chip.set('flowgraph', flow, step, index, metric, 'goal', 0)
elif metric in ('cellarea', 'peakpower', 'standbypower'):
    chip.set('flowgraph', flow, step, index, 'weight', metric, 1.0)
else:
    chip.set('flowgraph', flow, step, index, 'weight', metric, 0.001)

In addition to step wise minimization, metrics are used by the summary() function to present a dashboard view of the compilation results, and can be accessed through set()/get() by the user to create custom reporting and optimization loops. The metrics are cleared before each step/index run and then updated by the post_process() function for each tool. For an example of post_process setup, see the openroad module.

The following table shows a summary of all the available metrics. For a complete descriptions, refer to the Schema section of the reference manual.

metric	description
errors	Metric: total errors
warnings	Metric: total warnings
drvs	Metric: total drvs
unconstrained	Metric: total unconstrained
coverage	Metric: coverage
security	Metric: security
luts	Metric: FPGA LUTs
dsps	Metric: FPGA DSP slices
brams	Metric: FPGA BRAM tiles
cellarea	Metric: cellarea
totalarea	Metric: totalarea
utilization	Metric: area utilization
peakpower	Metric: peakpower
averagepower	Metric: averagepower
dozepower	Metric: dozepower
idlepower	Metric: idlepower
leakagepower	Metric: leakagepower
sleeppower	Metric: sleeppower
irdrop	Metric: peak IR drop
holdpaths	Metric: holdpaths
setuppaths	Metric: setuppaths
holdslack	Metric: holdslack
holdwns	Metric: holdwns
holdtns	Metric: holdtns
setupslack	Metric: setupslack
setupwns	Metric: setupwns
setuptns	Metric: setuptns
macros	Metric: macros
cells	Metric: cells
registers	Metric: registers
buffers	Metric: buffers
transistors	Metric: transistors
pins	Metric: pins
nets	Metric: nets
vias	Metric: vias
wirelength	Metric: wirelength
overflow	Metric: overflow
memory	Metric: memory
exetime	Metric: exetime
tasktime	Metric: tasktime
totaltime	Metric: totaltime