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35 lines
1.7 KiB
ReStructuredText
35 lines
1.7 KiB
ReStructuredText
.. meta::
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:description: Learn what causes oversubscription.
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:keywords: warning, log, gpu, performance penalty, help
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*******************************************************************
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Oversubscription of hardware resources in AMD Instinct accelerators
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*******************************************************************
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When an AMD Instinct™ MI series accelerator enters an oversubscribed state, the ``amdgpu`` driver outputs the following
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message.
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``amdgpu: Runlist is getting oversubscribed. Expect reduced ROCm performance.``
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Oversubscription occurs when application demands exceed the available hardware resources. In an oversubscribed
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state, the hardware scheduler tries to manage resource usage in a round-robin fashion. However,
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this can result in reduced performance, as resources might be occupied by applications or queues not actively
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submitting work. The granularity of hardware resources occupied by an inactive queue can be in the order of
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milliseconds, during which the accelerator or GPU is effectively blocked and unable to process work submitted by other
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queues.
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What triggers oversubscription?
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===============================
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The system enters an oversubscribed state when one of the following conditions is met:
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* **Hardware queue limit exceeded**: The number of user-mode compute queues requested by applications exceeds the
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hardware limit of 24 queues for current Instinct accelerators.
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* **Virtual memory context slots exceeded**: The number of user processes exceeds the number of available virtual memory
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context slots, which is 11 for current Instinct accelerators.
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* **Multiple processes using cooperative workgroups**: More than one process attempts to use the cooperative workgroup
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feature, leading to resource contention.
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