drivers/nvme/host/core.c | 24 ++++++++++------ drivers/nvme/host/nvme.h | 6 ++++ drivers/nvme/host/sysfs.c | 59 +++++++++++++++++++++++++++++++++++++++ 3 files changed, 81 insertions(+), 8 deletions(-)
From: Yaxiong Tian <tianyaxiong@kylinos.cn>
This series enhances NVMe APST (Autonomous Power State Transition) support by:
1. Adding warnings for PST table allocation failures
2. Exposing APST tables via sysfs for runtime inspection
3. Providing per-controller sysfs interface for APST configuration
The changes allow better visibility and control of power management settings
through userspace tools while maintaining the existing functionality.
Yaxiong Tian (3):
nvme: Add warning for PST table memory allocation failure in
nvme_configure_apst
nvme: add sysfs interface for APST table updates
nvme: add per-controller sysfs interface for APST configuration
Changes in v2
Add mutex_lock in nvme_set_latency_tolerance() for Potential competition
between nvme_set_latency_tolerance() and apst_update_store().
Changes in v3
In PACH nvme: add sysfs interface for APST table updates,Add why dynamic APST
updates are needed in the commit message, fix code formatting issues.
drivers/nvme/host/core.c | 24 ++++++++++------
drivers/nvme/host/nvme.h | 6 ++++
drivers/nvme/host/sysfs.c | 59 +++++++++++++++++++++++++++++++++++++++
3 files changed, 81 insertions(+), 8 deletions(-)
--
2.25.1
On Tue, Apr 01, 2025 at 05:22:06PM +0800, Yaxiong Tian wrote: > From: Yaxiong Tian <tianyaxiong@kylinos.cn> > > This series enhances NVMe APST (Autonomous Power State Transition) support by: > 1. Adding warnings for PST table allocation failures That looks fine. > 2. Exposing APST tables via sysfs for runtime inspection > 3. Providing per-controller sysfs interface for APST configuration Who is going to use this and how? We'll need proper tools for that, and in general I'd prefer to have a common set of policies for APST configurations and not random people coming up with lots of random policies.
在 2025/4/3 12:25, Christoph Hellwig 写道:
> On Tue, Apr 01, 2025 at 05:22:06PM +0800, Yaxiong Tian wrote:
>> From: Yaxiong Tian <tianyaxiong@kylinos.cn>
>>
>> This series enhances NVMe APST (Autonomous Power State Transition) support by:
>> 1. Adding warnings for PST table allocation failures
>
> That looks fine.
>
>> 2. Exposing APST tables via sysfs for runtime inspection
>> 3. Providing per-controller sysfs interface for APST configuration
>
> Who is going to use this and how? We'll need proper tools for that,
> and in general I'd prefer to have a common set of policies for APST
> configurations and not random people coming up with lots of random
> policies.
These two patches don't fundamentally change the APST configuration
policy, but rather enable users to configure various APST parameters in
real-time across different devices. As mentioned in commit
<ebd8a93aa4f5> ("nvme: extend and modify the APST configuration algorithm"):
1）This patch only introduces partial functionality from the Windows
driver - it doesn't enable dynamic regeneration of the APST table when
switching between AC power and battery power.
2) Additionally, using default configurations on certain brand SSDs has
been observed to increase power consumption.
Therefore, when a system contains multiple drives and users require
different configurations for AC vs battery power scenarios, real-time
APST configuration updates across different devices become necessary.It
must be said that configuring these parameters is difficult for average
users, but they can still use the original default settings. However,
for advanced users looking to optimize their devices, this provides them
with the necessary interface.
As for providing suitable tools for users, I suppose every advanced user
has their own preferences and approaches. For example, one could trace
device idle time statistics through trace events (e.g., nvme_complete_rq
→ nvme_setup_cmd) and use that data as a reference to configure
apst_primary_timeout_ms.
For example，The device idle time distribution under specific operating
conditions is shown below (unit: nanoseconds):
We can set apst_primary_timeout_ms to 32ms, which ensures that over 99%
of NVMe commands remain unaffected by APST.
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On Thu, Apr 03, 2025 at 03:05:37PM +0800, Yaxiong Tian wrote:
> These two patches don't fundamentally change the APST configuration policy,
> but rather enable users to configure various APST parameters in real-time
> across different devices. As mentioned in commit <ebd8a93aa4f5> ("nvme:
> extend and modify the APST configuration algorithm"):
And who are those users? What tools do they use. What settings do they
set and why?
在 2025/4/4 16:29, Christoph Hellwig 写道:
> On Thu, Apr 03, 2025 at 03:05:37PM +0800, Yaxiong Tian wrote:
>> These two patches don't fundamentally change the APST configuration policy,
>> but rather enable users to configure various APST parameters in real-time
>> across different devices. As mentioned in commit <ebd8a93aa4f5> ("nvme:
>> extend and modify the APST configuration algorithm"):
>
> And who are those users? What tools do they use. What settings do they
> set and why?
The three issues you mentioned were actually partially addressed in the
previous email, or at least touched upon.
In any case, I agree with applying a universal setting for APST, as I
don’t have a good tool to handle this either Now.
On 4/1/25 02:22, Yaxiong Tian wrote: > From: Yaxiong Tian<tianyaxiong@kylinos.cn> > > This series enhances NVMe APST (Autonomous Power State Transition) support by: > 1. Adding warnings for PST table allocation failures > 2. Exposing APST tables via sysfs for runtime inspection > 3. Providing per-controller sysfs interface for APST configuration > > The changes allow better visibility and control of power management settings > through userspace tools while maintaining the existing functionality. For the series looks good, I believe it is tested with blktest and there are no issues ... Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com> -ck
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