8. The InTime Flow

8.1. Tool Flow Overview

Here are steps which help FPGA designers achieve design goals and targets in the fastest way possible.

Typical steps in the flow are shown in Figure 28.

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Figure 28: The InTime Tool Flow

The flow’s starting point is an FPGA project created separately in an FPGA vendor tool.

When InTime starts, it detects existing synthesis and place-and-route results for the active revision/run (also known as the default revision) in the project before continuing. If results are not available the user will be prompted to let InTime build the active revision/run before proceeding. The default revision then becomes the base revision of the strategy evaluation step. Using the base revision, InTime generates strategies which are optimized for the design.

In the strategy evaluation step, InTime runs builds for all generated strategies. Users can define different run targets (local machine, private server farm, Amazon cloud) to run these builds, effectively scaling the number of concurrent runs based on the compute resources available (see Understanding Run Targets for details). Once completed, the results of all strategies are analyzed, collated and stored in InTime. This way, InTime builds up a comprehensive audit of all builds performed on all designs.

Before going into more detail, it is worth pausing to look at the Strategy Generation step.

8.2. Strategy Generation

When InTime generates strategies, it uses built-in knowledge that is optimized for each design. This knowledge leads to strategies with higher probabilities of improving the design’s performance in order to meet design goals. Figure 29 shows how this process works and how it becomes smarter and better at predicting strategies over time.

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Figure 29: Strategy Generation In InTime

The latest database ships with InTime and is the basis for future learning. Each time InTime completes a set of builds, it learns from the results and associates them with the project on which they were based.

8.3. Bringing It Together

The integrated flow diagram in Figure 30 shows how strategy generation ties into the tool flow, providing a clearer picture of how the full InTime flow works.

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Figure 30: The Full InTime Tool Flow

Once all strategy outcomes have been evaluated InTime determines if the design goal and targets have been met. If so, InTime has succeeded. If not, a next iteration of the flow can be started using the best result of the previous iteration as the basis (referred to as the parent revision throughout the documentation) upon which subsequent strategies will be generated.

You can easily customize the flow to cater to the needs of a wide range of situations and applications. Using a number of carefully selected Flow Properties, you will be able to generate strategies in different ways and get to different outcomes. For example, instead of meeting timing, you can explore various placement and routing possibilities for utilization.

To abstract the complexities of the customizable flow, InTime uses the concept of Deciding which recipe to use. Recipes abstract the flow from the user and provides the user with different customizations of the InTime flow steps to solve specific design problems.