Re: [PATCH]PCIE ASPM support - takes 2

[Shaohua Li <shaohua.li@intel.com>]

On Tue, 2008-01-15 at 22:56 -0500, Valdis.Kletnieks@vt.edu wrote:
> On Tue, 15 Jan 2008 13:02:26 +0800, Shaohua Li said:
> 
> > In my test, power difference between powersave mode and performance mode
> > is about 1.3w in a system with 3 PCIE links.
> 
> Do you have any numbers on what the added latency is for powersave mode, and
> a rough idea of how quickly chipsets will drop to low-power? It may affect
> usability a lot if it's "adds 10ms latency after 100ms idle" or "adds 100ms
> latency after 5 seconds idle" or some other pattern...
> 
> (The chipset in my laptop claims to be an 82801G with 4 PCI-Express ports on
> it - I'm trying to get a rough idea what usage I'd get out of that feature..)
No, I thought to get the latency impact with ASPM enabled, but haven't
found a way to measure it. This is why the default setting of ASPM
currently is using BIOS setting.

Thanks,
Shaohua