RE: [PATCH]PCIE ASPM support - takes 3

From: Li, Shaohua
Date: Fri Jan 25 2008 - 03:43:58 EST


>
>
>Hi!
>
>> v3->v2, fixed the issues Matthew Wilcox raised.
>>
>> PCI Express ASPM defines a protocol for PCI Express components in the
D0
>> state to reduce Link power by placing their Links into a low power
state
>> and instructing the other end of the Link to do likewise. This
>> capability allows hardware-autonomous, dynamic Link power reduction
>> beyond what is achievable by software-only controlled power
management.
>> However, The device should be configured by software appropriately.
>> Enabling ASPM will save power, but will introduce device latency.
>
>How big is the latency? 1msec? 10msec? 100usec?
Haven't accurate number, but in one device, it declaims L0s latency is <
128ns, L1 latency is < 64us.

Thanks,
Shaohua
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