On Tue, Jun 22, 2010 at 12:38:03PM -0700, Luis R. Rodriguez wrote: > On Tue, Jun 22, 2010 at 12:37 PM, Luis R. Rodriguez <mcgrof@xxxxxxxxx> wrote: > > On Tue, Jun 22, 2010 at 12:31 PM, Johannes Stezenbach <js@xxxxxxxxx> wrote: > >> > >> 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. > > > > 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. OK, let me put the question another way: If enabling ASPM comes with a performance penalty (which is not unexpected, there is usually a tradeoff between performance and power consumption), do you think a boot time option (pcie_aspm=) or compile time option (CONFIG_PCIEASPM) is the right user interface? But meanwhile I found that CONFIG_PCIEASPM has a runtime interface, /sys/module/pcie_aspm/parameters/policy. http://lwn.net/Articles/266585/ I have not tested it on my N130 yet. Johannes -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
