From: "Luis R. Rodriguez" <mcgrof@gmail.com>
To: Johannes Stezenbach <js@sig21.net>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>,
Jussi Kivilinna <jussi.kivilinna@mbnet.fi>,
Maxim Levitsky <maximlevitsky@gmail.com>,
David Quan <David.Quan@atheros.com>,
Bob Copeland <me@bobcopeland.com>,
"Luis R. Rodriguez" <mcgrof@bombadil.infradead.org>,
ath5k-devel@venema.h4ckr.net, linux-wireless@vger.kernel.org,
linux-kernel <linux-kernel@vger.kernel.org>,
Jonathan May <jonathan.may@atheros.com>,
Tim Gardner <tim.gardner@canonical.com>
Subject: Re: [ath5k-devel] [PATCH v2] ath5k: disable ASPM
Date: Tue, 22 Jun 2010 12:38:03 -0700 [thread overview]
Message-ID: <AANLkTimsEkff4sMiMB_VyWqkZOjy9PIuJ4AiC95PASOZ@mail.gmail.com> (raw)
In-Reply-To: <AANLkTin1fAAgYTYegqaadkYIYP2NXRNRzCR48e-uIgYV@mail.gmail.com>
On Tue, Jun 22, 2010 at 12:37 PM, Luis R. Rodriguez <mcgrof@gmail.com> wrote:
> On Tue, Jun 22, 2010 at 12:31 PM, Johannes Stezenbach <js@sig21.net> wrote:
>> On Tue, Jun 22, 2010 at 07:44:26PM +0100, Matthew Garrett wrote:
>>> On Tue, Jun 22, 2010 at 11:28:20AM -0700, Luis R. Rodriguez wrote:
>>> >
>>> > Heh, this whole patch and thread was started because Jussi tested
>>> > ath5k with pcie_aspm=force (on a pre PCIE 1.1 device (?)) . I have
>>> > been trying to explain all along why this is a terrible idea to the
>>> > point we should probably just remove that code from the kernel. Hence
>>> > my side rants and explanations to justify my reasonings.
>>>
>>> Well, there's two things here. If you use force then you might get
>>> inappropriate ASPM. But if your BIOS enables ASPM on an old device, then
>>> booting *without* CONFIG_PCIE_ASPM will leave it turned on, and booting
>>> *with* CONFIG_PCIE_ASPM will turn it off. The Kconfig description is
>>> confusing - reality is that CONFIG_PCIE_ASPM enables logic that allows
>>> the kernel to modify the BIOS default, and disabling it makes the
>>> assumption that your BIOS did something sensible.
>>
>> Does CONFIG_PCIEASPM provide a way for the user to modifiy
>> the settings at runtime?
>
> You can tune ASPM settings at runtime, regardless of CONFIG_PCIEASPM. See:
>
> http://kernel.org/pub/linux/kernel/people/mcgrof/aspm/enable-aspm
> http://wireless.kernel.org/en/users/Documentation/ASPM
>
>> I have a Samsung N130 netbook which has a BIOS setting
>> called "CPU Power Saving Mode". When enabled it activates
>> ASPM L1 and L0s for the ethernet chip (Realtek RTL8102e, 100Mbit)
>> and the PCIE bridge (with the BIOS setting off it's just L1).
>> The result is that the ethernet througput is reduced to 25Mbit/s.
>> (The BIOS setting does not activa L0s for the Atheros AR9285 WLAN.)
>>
>> 99,9% of the time I want to enjoy the power savings,
>> but occationally I have to transfer some bulk data and would
>> like to switch the setting for a few minutes.
>>
>> Or, well, ideally I'd like to have power savings _and_ performance
>> at the same time without any manual intervention. I'm not sure
>> if this is a quirk of the N130 or if ASPM L0s always causes
>> performance degradation?
>
> L0s is not going to buy you much gains, getting at least L1 will
> however. L0s is just a further enhancement. I recommend you test by
> enabling L1 and L0s, check how longer your battery lasts and then test
> again with just L1. Then test without both L1 and L0s.
So defaults should always be sane and you should not have to play with
this stuff, unless you're a hacker, or are testing something for
development purposes. Tweaking ASPM settings is not something a user
should have to worry about. Period.
Luis
next prev parent reply other threads:[~2010-06-22 19:38 UTC|newest]
Thread overview: 73+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-05-28 10:09 [PATCH] ath5k: disable ASPM Jussi Kivilinna
2010-05-28 16:19 ` [ath5k-devel] " Pavel Roskin
2010-05-28 18:25 ` Jussi Kivilinna
2010-05-28 20:27 ` Pavel Roskin
2010-05-31 1:06 ` Bruno Randolf
2010-06-01 20:43 ` Luis R. Rodriguez
2010-05-28 17:40 ` Luis R. Rodriguez
2010-05-28 18:20 ` Jussi Kivilinna
2010-06-17 20:33 ` Maxim Levitsky
2010-06-18 8:20 ` Jussi Kivilinna
2010-06-18 9:09 ` [ath5k-devel] " RHS Linux User
2010-06-18 10:15 ` Maxim Levitsky
2010-06-18 10:49 ` Jussi Kivilinna
2010-06-18 11:05 ` Maxim Levitsky
2010-06-18 13:59 ` Bob Copeland
2010-06-18 14:11 ` Maxim Levitsky
2010-06-19 7:49 ` [PATCH v2] " Maxim Levitsky
2010-06-19 12:38 ` Bob Copeland
2010-06-19 13:02 ` Maxim Levitsky
2010-06-19 15:32 ` [PATCH v3] " Maxim Levitsky
2010-07-26 20:13 ` [ath5k-devel] " Luis R. Rodriguez
2010-07-26 20:49 ` Maxim Levitsky
2010-07-26 21:06 ` Luis R. Rodriguez
2010-07-26 21:14 ` Matthew Garrett
2010-07-26 22:20 ` Luis R. Rodriguez
2010-07-26 22:24 ` Matthew Garrett
2010-07-26 22:29 ` Luis R. Rodriguez
2010-07-26 21:17 ` Maxim Levitsky
2010-07-26 21:25 ` Matthew Garrett
2010-07-26 22:15 ` Luis R. Rodriguez
2010-07-26 22:21 ` Matthew Garrett
2010-07-26 22:26 ` Luis R. Rodriguez
2010-07-26 22:29 ` Matthew Garrett
2010-07-26 22:31 ` Luis R. Rodriguez
2010-07-26 22:33 ` Matthew Garrett
2010-07-26 22:43 ` Luis R. Rodriguez
2010-07-26 22:50 ` Matthew Garrett
2010-07-27 9:35 ` Maxim Levitsky
2010-07-27 15:57 ` Luis R. Rodriguez
2010-07-28 23:48 ` Maxim Levitsky
2010-07-29 0:06 ` Luis R. Rodriguez
2010-07-26 22:13 ` Luis R. Rodriguez
2010-07-26 22:56 ` Luis R. Rodriguez
2010-06-20 8:13 ` [ath5k-devel] [PATCH v2] " Luis R. Rodriguez
2010-06-20 11:18 ` Maxim Levitsky
2010-06-20 18:04 ` Maxim Levitsky
2010-06-21 5:53 ` Luis R. Rodriguez
2010-06-21 20:01 ` Jussi Kivilinna
2010-06-21 20:16 ` Maxim Levitsky
2010-06-21 20:33 ` Jussi Kivilinna
2010-06-21 20:39 ` Luis R. Rodriguez
2010-06-22 16:31 ` Matthew Garrett
2010-06-22 16:48 ` Luis R. Rodriguez
2010-06-22 16:52 ` Matthew Garrett
2010-06-22 17:17 ` Luis R. Rodriguez
2010-06-22 17:25 ` Matthew Garrett
2010-06-22 17:40 ` Luis R. Rodriguez
2010-06-22 17:50 ` Matthew Garrett
2010-06-22 18:28 ` Luis R. Rodriguez
2010-06-22 18:44 ` Matthew Garrett
2010-06-22 19:13 ` Luis R. Rodriguez
2010-06-22 19:31 ` Johannes Stezenbach
2010-06-22 19:37 ` Luis R. Rodriguez
2010-06-22 19:38 ` Luis R. Rodriguez [this message]
2010-06-23 14:39 ` Johannes Stezenbach
2010-06-23 16:28 ` Luis R. Rodriguez
2010-06-23 19:07 ` Johannes Stezenbach
2010-06-23 19:23 ` Johannes Stezenbach
2010-06-21 20:37 ` Luis R. Rodriguez
2010-06-21 23:55 ` Maxim Levitsky
2010-07-26 16:34 ` [PATCH] " Maxim Levitsky
2010-07-26 18:37 ` John W. Linville
2010-07-26 18:41 ` [ath5k-devel] " Luis R. Rodriguez
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