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Re: [PATCH 2/2] x86/mwait-idle: Customize IceLake server support

On 13.10.2020 05:02, Igor Druzhinin wrote:
> From: Chen Yu <yu.c.chen@xxxxxxxxx>
> On ICX platform, the C1E auto-promotion is enabled by default.
> As a result, the CPU might fall into C1E more offen than previous
> platforms. So disable C1E auto-promotion and expose C1E as a separate
> idle state.
> Beside C1 and C1E, the exit latency of C6 was measured
> by a dedicated tool. However the exit latency(41us) exposed
> by _CST is much smaller than the one we measured(128us). This
> is probably due to the _CST uses the exit latency when woken
> up from PC0+C6, rather than PC6+C6 when C6 was measured. Choose
> the latter as we need the longest latency in theory.
> Signed-off-by: Chen Yu <yu.c.chen@xxxxxxxxx>
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
> [Linux commit a472ad2bcea479ba068880125d7273fc95c14b70]
> Signed-off-by: Igor Druzhinin <igor.druzhinin@xxxxxxxxxx>

Acked-by: Jan Beulich <jbeulich@xxxxxxxx>



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