| |
|
 |
|
 |
|
|
|
| |
|
|
xen-devel
RE: [Xen-devel][PATCH 0/5] Add cpufreq pwr mgmt to Xen
|
To: |
"Langsdorf, Mark" <mark.langsdorf@xxxxxxx>, "Liu, Jinsong" <jinsong.liu@xxxxxxxxx>, <xen-devel@xxxxxxxxxxxxxxxxxxx> |
|
Subject: |
RE: [Xen-devel][PATCH 0/5] Add cpufreq pwr mgmt to Xen |
|
From: |
"Tian, Kevin" <kevin.tian@xxxxxxxxx> |
|
Date: |
Fri, 16 May 2008 12:59:16 +0800 |
|
Cc: |
"Nakajima, Jun" <jun.nakajima@xxxxxxxxx> |
|
Delivery-date: |
Thu, 15 May 2008 22:00:57 -0700 |
|
Envelope-to: |
www-data@xxxxxxxxxxxxxxxxxx |
|
In-reply-to: |
<6453C3CB8E2B3646B0D020C112613273C5AB7B@xxxxxxxxxxxxxxxxx> |
|
List-help: |
<mailto:xen-devel-request@lists.xensource.com?subject=help> |
|
List-id: |
Xen developer discussion <xen-devel.lists.xensource.com> |
|
List-post: |
<mailto:xen-devel@lists.xensource.com> |
|
List-subscribe: |
<http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe> |
|
List-unsubscribe: |
<http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe> |
|
References: |
<9D7649D18729DE4BB2BD7B494F7FEDC201400CB4@xxxxxxxxxxxxxxxxxxxxxxxxxxxx> <6453C3CB8E2B3646B0D020C112613273C5AB7B@xxxxxxxxxxxxxxxxx> |
|
Sender: |
xen-devel-bounces@xxxxxxxxxxxxxxxxxxx |
|
Thread-index: |
Aci0psbAJyAAXqNnQsOQlsmPt5l5EgCLz8lQAA4PRwA= |
|
Thread-topic: |
[Xen-devel][PATCH 0/5] Add cpufreq pwr mgmt to Xen |
>From: Langsdorf, Mark [mailto:mark.langsdorf@xxxxxxx]
>Sent: 2008年5月16日 5:55
>
>> The following patchset is to add processor P state power management
>> support to Xen X86.
>
>Is there any way to determine what frequencies the
>CPU is running at now? I think I have support for
>the AMD Architectural P-state driver working now,
>but it would be nice if there was a better way to
>test that it's working.
>
Mark, the efficient way to check current freq is cpu specific.
ACPI defines a way to read PERF_STATUS and then
compare to _PSS status field as confirmation whether the
transition succeeds. Corresponding MSR in Intel are
IA32_PERF_STATUS upon which cpufreq driver exacts to
compare freq table for actual value. As hardware coordination
is active, above value doesn't reflect the actual freq. Thus
there're a new MSR pair (MPERF/APERF) on Intel processors
to report the actual freq. You can check get_cur_freq_on_cpu
for all possible ways. I can't tell for AMD cpus but I guess
similar MSRs may also exist in your case.
Thanks,
Kevin
_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel
|
|
|
| |
|
Home