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AR# 11749

7.1i Timing Analyzer/TRCE/PAR - Long run times occur, or "ERROR:Portability:3 This Xilinx application has run out of memory..." is reported


General Description:

PAR, Trace, and Timing Analyzer have excessively long run times. The following error might also be reported:

"ERROR:Portability:3 This Xilinx application has run out of memory or has encountered a memory conflict."

Additionally, the PCF contains a very large number of timing constraints. The error or long run time does not occur if a PCF is not used.


Generally, increasing the number of timing constraints increases the run times for PAR, Trace, and Timing Analyzer. The constraint editor used in synthesis tools might generate large numbers of single-path timing constraints, greatly increasing run times (sometimes to the point of a memory error) in large designs.

To avoid this problem, consolidate constraints in the PCF using time groups or re-constrain the design by hand in a UCF or in the Xilinx Constraints Editor.

Some of the causes of this issue have been addressed in the latest 6.2i Service Pack, available at:

The first service pack containing the fix is 6.2i Service Pack 3.
AR# 11749
Date 12/01/2011
Status Archive
Type General Article