Running Multiple Implementation Strategies for Timing Closure - 2025.1 English - UG1700

For challenging designs, it can take multiple iterations of Vivado implementation using multiple different strategies to achieve timing closure. This topic shows you how to launch multiple implementation strategies at the same time in the hardware build (-t hw), and how to identify and use successful runs to generate the device binary and complete the build.

As explained in --vivado Options , the --vivado.impl.strategies command enables you to specify multiple strategies to run in a single build pass. The command line would look as follows:

v++ --link -s -g -t hw --platform xilinx_zcu102_base_202010_1 -I . \
--vivado.impl.strategies "Performance_Explore,Area_Explore" -o kernel.xclbin hello.xo

In the example above, the Performance_Explore and Area_Explore strategies are run simultaneously in the Vivado build to see which returns the best results. You can specify the ALL to have all available strategies run within the tool.

You can also determine this option in a configuration file in the following form:

#Vivado Implementation Strategies
[vivado]
impl.strategies=Performance_Explore,Area_Explore

The Vitis compiler automatically picks the first completed run results that meets timing to proceed with the build process and generate the device binary. However, you can also direct the tool to wait for all runs to see the result of all strategies. This would require the use of the {}ALL_IMPL{} macro to apply custom settings to all runs and the multiStrategiesWaitOnAllRuns directive to see the result of all strategies:

[advanced]
#param=compiler.multiStrategiesWaitOnAllRuns=1

[vivado]

impl.strategies=ALL
prop=run.{}ALL_IMPL{}.STEPS.PLACE_DESIGN.TCL.PRE=../../vpp_cfg/place_design_pre.tcl
prop=run.{}ALL_IMPL{}.STEPS.ROUTE_DESIGN.TCL.PRE=../../vpp_cfg/route_design_pre.tcl

compiler.multiStrategiesWaitOnAllRuns=0 represents the default behavior. If you want v++ to wait for all runs to complete, which will get their report files, change that parameter value to 1. This includes an overview of the implementation results, in addition to a Timing Summary report. Seeing all results will give you an indication on how hard it is to close timing for the tool for the all strategies that are allowed to run to completion. You can use this feature to review the different strategies and results.

You can also manually review the results of all implementation strategies after they have completed. Then, use the results of any of the implementation runs by using the --reuse_impl option as described in Using --to_step and Launching Vivado Interactively.