| # Avoiding overallocation of CPU and memory for OpenROAD builds |
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| Subcategory: Resource management |
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| ## Conversation |
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| ### oharboe |
| I am running into problems with too many OpenROAD binaries running in parallel when using Bazel ORFS layer.
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| I'm looking into whether I can get Bazel not to overuse CPUs in the system: https://groups.google.com/g/bazel-discuss/c/KVDcZ-EDfZw
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| What other options are there? Surely this is not a new problem. What does other types of toolchains do?
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| However, could and should OpenROAD be modified so that it communicates with other OpenROAD instances in the system and throttles usage to avoid overallocation of CPU and memory?
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| Idea:
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| - add new option to openroad `-limit <path>`
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| - this would cause openroad instances to communicate with eachother not to overallocate CPU and memory |
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| ### maliberty |
| This seems to be more about job scheduling than OR. Usually a job scheduler will have some ability to specify the required resources for a job. OR itself will allow you to give a max number of threads if that's helpful.
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| For example in [condor](https://htcondor.readthedocs.io/en/latest/users-manual/submitting-a-job.html):
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| ```
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| request_cpus = 1
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| request_memory = 1024M
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| request_disk = 10240K
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| ```
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| I don't think OR should try to solve this as you can run into the same issue between unrelated tools (yosys, klayout, or, etc). |
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| ### oharboe |
| Turns out there is an infinite loop, probably, in DRC. I thought things ground to a halt because of CPU thrashing, but the detailed router might actually be stuck here. https://github.com/The-OpenROAD-Project/OpenROAD/issues/4466
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| If there is some performance degradation like 30-50% when running multiple detailed routing in parallel, that's tolerable. |
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