SLR Net Crossing Reporting - 2021.2 English

Vivado Design Suite User Guide: Design Analysis and Closure Techniques (UG906)

Document ID
UG906
Release Date
2021-10-27
Version
2021.2 English

The SLR Net Crossing Reporting is only applicable to SSI Devices and reports the number of nets contained in a module that cross the SLR boundaries. For each module, the table provides further details of which SLRs are crossed by the nets. The following figure shows an example of the SLR Net Crossing Reporting table.

Note: When a net has loads in multiple SLRs, it is only counted once for the furthest cut. For example, a net driven from SLR0 to loads in SLR1, SLR2, and SLR3 is only counted once under the 0-3 cuts, with SLR3 being the "furthest fanout" from SLR0. This counting method enables to sum the number of nets under each column (0-1 Cuts, 1-2 Cuts, and so on) to match to total number of nets crossing, as each net is only counted once.
Figure 1. Example SLR Net Crossing Reporting Table

When analyzing the SLR Net Crossing Reporting Table of your design for Congestion and Timing QoR, look for the following:

  1. When using SSI Devices, the SSI placement directives can be beneficial for both timing and congestion.
  2. If a particular module that is crossing SLRs is consistently experiencing timing issues across multiple implementation runs using various placement directives, attempt light Pblocking to constrain the module to a single SLR.