Timing optimization method and apparatus based on output transition constraints, and computer device

A timing optimization apparatus based on output transition constraints, comprising:

• a target cell determining module, determining, based on a synthetic timing analysis result of a logical netlist, all candidate target cells requiring timing optimization;
• and
• an optimization module, performing timing optimization on each candidate target cell, and comprising an updating unit, a timing analysis unit, a slew determining unit, and a delay boost ratio determining unit, wherein
• the updating unit updates the candidate target cell to increase an area of the candidate target cell;
• the timing analysis unit performs timing analysis on a path where the updated candidate target cell is located, and acquires updated timing parameters, the timing parameters comprising output slew and delay of the candidate target cell;
• the slew determining unit determines whether the output slew of the updated candidate target cell is less than a preset output slew threshold;
• if the output slew of the updated candidate target cell is less than the preset output slew threshold, timing optimization of the current candidate target cell ends,
• otherwise, the delay boost ratio determining unit determines, based on delay output from previous timing analysis, whether a delay boost ratio of the updated candidate target cell is less than a set delay boost ratio threshold;
• if the delay boost ratio of the updated candidate target cell is less than the set delay boost ratio threshold, timing optimization of the current candidate target cell ends, otherwise, the above steps are repeatedly performed to continue updating the area of the candidate target cell until the output slew of the candidate target cell is less than the output slew threshold or the delay boost ratio of the candidate target cell is less than the delay boost ratio threshold;
• wherein the timing optimization apparatus based on output transition constraints further comprises a power determining module and a slew adjusting module, upon completion of one iteration of timing optimization, the power determining module determining whether output power of a circuit is less than design power;
• if the output power of the circuit is less than the design power, the slew adjusting module decreasing the output slew threshold, and the next iteration of timing optimization being performed on all the candidate target cells based on the decreased output slew threshold.

A timing optimization apparatus based on output transition constraints, comprising:

• a target cell determining module, determining, based on a synthetic timing analysis result of a logical netlist, all candidate target cells requiring timing optimization;
• and
• an optimization module, performing timing optimization on each candidate target cell, and comprising an updating unit, a timing analysis unit, a slew determining unit, and a delay boost ratio determining unit, wherein
• the updating unit updates the candidate target cell to increase an area of the candidate target cell;
• the timing analysis unit performs timing analysis on a path where the updated candidate target cell is located, and acquires updated timing parameters, the timing parameters comprising output slew and delay of the candidate target cell;
• the slew determining unit determines whether the output slew of the updated candidate target cell is less than a preset output slew threshold;
• if the output slew of the updated candidate target cell is less than the preset output slew threshold, timing optimization of the current candidate target cell ends,
• otherwise, the delay boost ratio determining unit determines, based on delay output from previous timing analysis, whether a delay boost ratio of the updated candidate target cell is less than a set delay boost ratio threshold;
• if the delay boost ratio of the updated candidate target cell is less than the set delay boost ratio threshold, timing optimization of the current candidate target cell ends, otherwise, the above steps are repeatedly performed to continue updating the area of the candidate target cell until the output slew of the candidate target cell is less than the output slew threshold or the delay boost ratio of the candidate target cell is less than the delay boost ratio threshold;
• wherein in the case that the given logical netlist has a plurality of clock sources, the target cell determining module classifies all the candidate target cells based on types of the clock sources before all the candidate target cells are optimized;
• and during timing optimization of a plurality of candidate target cells of the same category, updating of areas of the candidate target cells takes into account clock skew of corresponding clock sources.