linux-kernel - RE: [PATCH v3 0/3] nvme: Add sysfs interface for APST configuration management

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID:
 <BY5PR16MB33964D444ED2B1E00E94B99792AB2@BY5PR16MB3396.namprd16.prod.outlook.com>
Date: Sun, 6 Apr 2025 09:14:18 +0000
From: Alexey Bogoslavsky <Alexey.Bogoslavsky@...disk.com>
To: Christoph Hellwig <hch@....de>, Yaxiong Tian <iambestgod@...com>
CC: "kbusch@...nel.org" <kbusch@...nel.org>, "axboe@...nel.dk"
	<axboe@...nel.dk>, "sagi@...mberg.me" <sagi@...mberg.me>,
	"chaitanyak@...dia.com" <chaitanyak@...dia.com>,
	"linux-nvme@...ts.infradead.org" <linux-nvme@...ts.infradead.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>, Yaxiong Tian
	<tianyaxiong@...inos.cn>, "alexey.bogoslavsky@....com"
	<alexey.bogoslavsky@....com>, Yehuda Hahn <Yehuda.Hahn@...disk.com>
Subject: RE: [PATCH v3 0/3] nvme: Add sysfs interface for APST configuration
 management

Hi Yaxiong Tian,
The ability to configure the APST-related thresholds is not the essence of the commit
you mentioned, but rather an added bonus, which I suppose not many people actually use.
The actual change is about reducing the number of non-operational states in the APST table to just two,
regardless of the number of non-operational states advertised by the device, and, more importantly,
removal of the linear dependency between the ENLAT and EXLAT and the ITPT which, before the change
was made, caused an unreasonably high ITPT in devices with high latencies, which, in turn, prevented
transitions to non-operational states and led to an unjustified waste of power. The modified code
was tested thoroughly and showed significant improvement for some devices and only a minor negative effect 
for others. All results appear in the commit's description.

Thanks,
Alexey

-----Original Message-----
From: Christoph Hellwig <hch@....de> 
Sent: Friday, April 4, 2025 11:30 AM
To: Yaxiong Tian <iambestgod@...com>
Cc: Christoph Hellwig <hch@....de>; kbusch@...nel.org; axboe@...nel.dk; sagi@...mberg.me; chaitanyak@...dia.com; linux-nvme@...ts.infradead.org; linux-kernel@...r.kernel.org; Yaxiong Tian <tianyaxiong@...inos.cn>; alexey.bogoslavsky@....com
Subject: Re: [PATCH v3 0/3] nvme: Add sysfs interface for APST configuration management

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?