From: james_p_freyensee@linux.intel.com (J Freyensee)
Subject: [PATCH v4 0/3] nvme power saving
Date: Fri, 16 Sep 2016 17:49:55 -0700 [thread overview]
Message-ID: <1474073395.10494.13.camel@linux.intel.com> (raw)
In-Reply-To: <cover.1474049701.git.luto@kernel.org>
On Fri, 2016-09-16@11:16 -0700, Andy Lutomirski wrote:
> Hi all-
>
> Here's v4 of the APST patch set.??The biggest bikesheddable thing (I
> think) is the scaling factor.??I currently have it hardcoded so that
> we wait 50x the total latency before entering a power saving state.
> On my Samsung 950, this means we enter state 3 (70mW, 0.5ms entry
> latency, 5ms exit latency) after 275ms and state 4 (5mW, 2ms entry
> latency, 22ms exit latency) after 1200ms.??I have the default max
> latency set to 25ms.
>
> FWIW, in practice, the latency this introduces seems to be well
> under 22ms, but my benchmark is a bit silly and I might have
> measured it wrong.??I certainly haven't observed a slowdown just
> using my laptop.
>
> This time around, I changed the names of parameters after Jay
> Frayensee got confused by the first try.??Now they are:
>
> ?- ps_max_latency_us in sysfs: actually controls it.
> ?- nvme_core.default_ps_max_latency_us: sets the default.
>
> Yeah, they're mouthfuls, but they should be clearer now.
>?
I took the patches and applied them to one of my NVMe fabric hosts on
my NVMe-over-Fabrics setup. ?Basically, it doesn't test much other than
Andy's explanation that?"ps_max_latency_us" does not appear in any of
/sys/block/nvmeXnY sysfs nodes (I have 7) so seems good to me on this
front.
Tested-by: Jay Freyensee <james_p_freyensee at linux.intel.com>
[jpf: defaults benign to NVMe-over-Fabrics]
WARNING: multiple messages have this Message-ID (diff)
From: J Freyensee <james_p_freyensee@linux.intel.com>
To: Andy Lutomirski <luto@kernel.org>,
Keith Busch <keith.busch@intel.com>, Jens Axboe <axboe@fb.com>
Cc: linux-nvme@lists.infradead.org, Christoph Hellwig <hch@lst.de>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v4 0/3] nvme power saving
Date: Fri, 16 Sep 2016 17:49:55 -0700 [thread overview]
Message-ID: <1474073395.10494.13.camel@linux.intel.com> (raw)
In-Reply-To: <cover.1474049701.git.luto@kernel.org>
On Fri, 2016-09-16 at 11:16 -0700, Andy Lutomirski wrote:
> Hi all-
>
> Here's v4 of the APST patch set. The biggest bikesheddable thing (I
> think) is the scaling factor. I currently have it hardcoded so that
> we wait 50x the total latency before entering a power saving state.
> On my Samsung 950, this means we enter state 3 (70mW, 0.5ms entry
> latency, 5ms exit latency) after 275ms and state 4 (5mW, 2ms entry
> latency, 22ms exit latency) after 1200ms. I have the default max
> latency set to 25ms.
>
> FWIW, in practice, the latency this introduces seems to be well
> under 22ms, but my benchmark is a bit silly and I might have
> measured it wrong. I certainly haven't observed a slowdown just
> using my laptop.
>
> This time around, I changed the names of parameters after Jay
> Frayensee got confused by the first try. Now they are:
>
> - ps_max_latency_us in sysfs: actually controls it.
> - nvme_core.default_ps_max_latency_us: sets the default.
>
> Yeah, they're mouthfuls, but they should be clearer now.
>
I took the patches and applied them to one of my NVMe fabric hosts on
my NVMe-over-Fabrics setup. Basically, it doesn't test much other than
Andy's explanation that "ps_max_latency_us" does not appear in any of
/sys/block/nvmeXnY sysfs nodes (I have 7) so seems good to me on this
front.
Tested-by: Jay Freyensee <james_p_freyensee@linux.intel.com>
[jpf: defaults benign to NVMe-over-Fabrics]
next prev parent reply other threads:[~2016-09-17 0:49 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-16 18:16 [PATCH v4 0/3] nvme power saving Andy Lutomirski
2016-09-16 18:16 ` Andy Lutomirski
2016-09-16 18:16 ` [PATCH v4 1/3] nvme/scsi: Remove power management support Andy Lutomirski
2016-09-16 18:16 ` Andy Lutomirski
2016-09-16 23:37 ` J Freyensee
2016-09-16 23:37 ` J Freyensee
2016-09-16 18:16 ` [PATCH v4 2/3] nvme: Pass pointers, not dma addresses, to nvme_get/set_features() Andy Lutomirski
2016-09-16 18:16 ` Andy Lutomirski
2016-09-16 18:16 ` [PATCH v4 3/3] nvme: Enable autonomous power state transitions Andy Lutomirski
2016-09-16 18:16 ` Andy Lutomirski
2016-09-17 0:49 ` J Freyensee [this message]
2016-09-17 0:49 ` [PATCH v4 0/3] nvme power saving J Freyensee
2016-09-22 0:11 ` Andy Lutomirski
2016-09-22 0:11 ` Andy Lutomirski
2016-09-22 13:21 ` Christoph Hellwig
2016-09-22 13:21 ` Christoph Hellwig
2016-09-22 14:23 ` Jens Axboe
2016-09-22 14:23 ` Jens Axboe
2016-09-22 20:11 ` Andy Lutomirski
2016-09-22 20:11 ` Andy Lutomirski
2016-09-22 20:43 ` Jens Axboe
2016-09-22 20:43 ` Jens Axboe
2016-09-22 21:33 ` J Freyensee
2016-09-22 21:33 ` J Freyensee
2016-09-22 22:15 ` Andy Lutomirski
2016-09-22 22:15 ` Andy Lutomirski
2016-10-28 0:06 ` Andy Lutomirski
2016-10-28 0:06 ` Andy Lutomirski
2016-10-28 5:29 ` Christoph Hellwig
2016-10-28 5:29 ` Christoph Hellwig
2016-09-22 22:16 ` Keith Busch
2016-09-22 22:16 ` Keith Busch
2016-09-22 22:07 ` Jens Axboe
2016-09-22 22:07 ` Jens Axboe
2016-09-23 23:42 ` Christoph Hellwig
2016-09-23 23:42 ` Christoph Hellwig
2016-09-24 16:55 ` Jens Axboe
2016-09-24 16:55 ` Jens Axboe
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