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AR# 64002

XAPP589-XAPP1241-v2.4- Long runtime during route_design can lead to a crash in 2016.1


A longer than usual runtime has been reported during the call to pre_route.tcl. The message PICXO-106 shows a very high number of seconds to complete pre_route.tcl.

In 2016.1, the tool crashes with an "out of memory" message.

Why is the runtime increased? How can I speed it up?


The runtime is increased because the license server is called every time route_design is called.

pre_route.tcl calls route_design a number of times and so the runtime can increase significantly if the license server checkout is slow.

To work around the problem in versions prior to 2016.1:

  1. Understand why the call to the license server takes so long.
    Are there any unknown servers on the LM_LICENSE_FILE environment variable?
    Is the license server first on the list?

  2. Borrow a license locally. This feature is available from Vivado 2015.1 onward.

  3. Involve a licensing expert to resolve points 1 and 2 above.

  4. If the two options above do not work, the log file outputs the necessary routing constraints to speed up runtime on the next run.

Note: Two messages relating to PICXO-210 appear. The first one states that the Tcl file should be used post placement but this is incorrect. It must be used pre-placement or post opt_design.

To work around the problem in Vivado 2016.1:

  1. Use option 4 above in 2015.4 and use the generated constraints in 2016.1

The next release, v2.5, will resolve the runtime and crash issue.

Linked Answer Records

Master Answer Records

Answer Number Answer Title Version Found Version Resolved
56136 XAPP589 - XAPP1241 - All Digital VCXO Replacement (PICXO) - Design Assistant / Master Answer Record N/A N/A
AR# 64002
Date 05/30/2016
Status Active
Type General Article
  • SoC
  • Artix-7
  • Kintex UltraScale
  • More
  • Kintex-7
  • Kintex-7Q
  • Virtex UltraScale
  • Virtex-7
  • Virtex-7Q
  • Less
  • Vivado Design Suite
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