Re: [edk2-devel] [PATCH] UefiPayloadPkg: Add macro to enable selection of timer

["Nate DeSimone" <nathaniel.l.desimone@intel.com>]

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Hi Benjamin,

We consider using the LAPIC as a timer to be technically superior because it is closer to the CPU. The HPET is a PCH device, which means all access to the timer needs go from CPU -> Home Agent -> Fabric/IO Ring -> DMI Controller -> PCH. Using the LAPIC cuts this path to just the Home Agent. That reduces access latency, which for a timer means higher resolution.

Hope that helps,
Nate

From: devel@edk2.groups.io <devel@edk2.groups.io> on behalf of Benjamin Doron <benjamin.doron00@gmail.com>
Date: Tuesday, January 9, 2024 at 3:48 PM
To: Ma <>, Ma, Hua <Hua.Ma@intel.com>, devel@edk2.groups.io <devel@edk2.groups.io>
Subject: Re: [edk2-devel] [PATCH] UefiPayloadPkg: Add macro to enable selection of timer
Hi,
Are there platforms that will use this? What advantages does using the LAPIC as a timer offer? Thanks.

Regards,
Benjamin



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