From: hch@infradead.org (Christoph Hellwig)
Subject: NVMe APST high latency power states being skipped
Date: Tue, 23 May 2017 00:17:05 -0700 [thread overview]
Message-ID: <20170523071705.GD16776@infradead.org> (raw)
In-Reply-To: <CAAd53p5pxgO-n0K4khAsYAcWw64tNJwtPwbMHaPksVQMLeXJmA@mail.gmail.com>
On Mon, May 22, 2017@05:04:15PM +0800, Kai-Heng Feng wrote:
> Hi Andy,
>
> Currently, if a power state tradition requires high latency, it may be
> skipped [1] based on the value of ps_max_latency_us in
> nvme_configure_apst():
>
> if (total_latency_us > ctrl->ps_max_latency_us)
> continue;
>
> Right now ps_max_latency_us defaults to 25000, but some consumer level
> NVMe have much higher latency.
> I understand this value is configurable, but I am wondering if it's
> possible to ignore the latency on consumer devices, probably based on
> chassis type, so consumer devices can get most NVMe power saving out
> of the box?
What is your proposed change? Do you have any numbers on how this
improves power consumption for given workloads and what the performance
impact is on common benchmarks?
next prev parent reply other threads:[~2017-05-23 7:17 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-05-22 9:04 NVMe APST high latency power states being skipped Kai-Heng Feng
2017-05-23 7:17 ` Christoph Hellwig [this message]
2017-05-23 8:06 ` Kai-Heng Feng
2017-05-23 9:42 ` Christoph Hellwig
2017-05-23 19:35 ` Andy Lutomirski
2017-05-23 19:56 ` Mario.Limonciello
2017-05-23 20:01 ` Andy Lutomirski
2017-05-23 20:19 ` Mario.Limonciello
2017-05-23 21:11 ` Andy Lutomirski
2017-05-23 22:09 ` Mario.Limonciello
2017-05-24 4:53 ` Kai-Heng Feng
2017-05-24 5:31 ` Andy Lutomirski
2017-05-25 8:21 ` Kai-Heng Feng
2017-05-26 9:25 ` Christoph Hellwig
2017-06-01 8:19 ` Kai-Heng Feng
2017-06-01 11:32 ` Christoph Hellwig
2017-06-02 7:08 ` Kai-Heng Feng
2017-06-02 7:13 ` Christoph Hellwig
2017-06-06 9:54 ` Christoph Hellwig
2017-06-06 15:57 ` Andy Lutomirski
2017-06-07 6:19 ` Kai-Heng Feng
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