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In the previous blog, Recharacterize What Matters - Save Time!, Abha told you about recharacterizing a failed or missing arc in Liberate. The Liberate MX Memory Characterization solution also has a similar capability, known as the incremental run, which reuses most of the already available data and characterizes only the failed or additional arcs.
We often get queries from users about having an incomplete Liberty file that has failed arcs due to farm instability, NFS issues, etc. With an incomplete Liberty file, you may be apprehensive about whether to run the entire characterization again or just perform an incremental run to generate the complete Liberty file.
When the incremental run is enabled, Liberate MX automatically detects and characterizes only the failed and/or newly added arcs. You can enable the incremental flow for new or failed arcs by analyzing the library database (LDB) and setting the reuse Liberate MX parameters.
Following is the global command which enables reuse of all the arcs:
Liberate MX also offers a variety of granular controls for users to choose from to decide if they want to rerun the characterization only for a specific set of arc types. The following parameters to allow you to perform incremental run based on the arc types:
Let us now look at various scenarios where performing an incremental run can save you time and effort:
Scenario 1: Step by step setting up new memory characterization runConsider that you are setting up the flow from scratch and are working on a specific arc type. Then you keep appending arc types in same run. In such a case, if you enable the incremental run, Liberate MX will reuse the completed arcs and save overall time.
Scenario 2: Recharacterizing the updated arc types and reusing the others in a runNow, assume that there is an update in models for specific arc types, such as power and leakage arcs. You can choose to rerun only the power and leakage arcs and reuse the other arcs (such as timing and noise) .
Scenario 3: Adding a new arc after the initial characterization run When you add a new arc, Liberate MX reuses all completed arcs and runs only the newly added arc. Liberate MX does this by automatically identifying what already exists in database and what is needed to create complete liberty file.
Scenario 4: Running failed arcsThere are always cases when a certain arc fails. Sometimes, you may be able to successfully rerun that arc after updating the simulator version, settings, changing the host-OS, memory etc. At times, you may need to debug and fix the issue. In such a scenario, when you rerun the same job, Liberate MX automatically identifies what was missing and reruns only the required arcs to create a complete Liberty file.
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Kamlesh Singh Dodiya