18 lines
920 B
YAML
18 lines
920 B
YAML
---
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deprecations:
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- |
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Support to monitor performance events for Intel CMT (Cache
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Monitoring Technology, or "CQM" in Linux kernel parlance) -- namely
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``cmt``, ``mbm_local`` and ``mbm_total`` -- via the config attribute
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``[libvirt]/enabled_perf_events`` is now *deprecated* from Nova, and
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will be *removed* in the "Stein" release. Otherwise, if you have
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enabled those events, and upgraded to Linux kernel 4.14 (or suitable
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downstream version), it will result in instances failing to boot.
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That is because the Linux kernel has deleted the `perf` framework
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integration with Intel CMT, as the feature was broken by design --
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an incompatibility between Linux's `perf` infrastructure and Intel
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CMT. It was removed in upstream Linux version v4.14; but bear in
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mind that downstream Linux distributions with lower kernel versions
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than 4.14 have backported the said change.
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