On Sun, 2007-05-13 at 19:24 +0200, Thorsten Leemhuis wrote: > On 13.05.2007 19:06, Arjan van de Ven wrote: > > On Sun, 2007-05-13 at 23:52 +1000, David Timms wrote: > >> Arjan van de Ven wrote: > >>> some of you already know that I've been working on getting Linux (and > >>> Fedora) to be a lot better about power usage on laptops by avoiding > >>> spurious wakeups and context switches and such (look at the "wakeup" bug > >>> in fedora bugzilla ;). > >> ... > >> Would this tool help one in tracing the cause of disk accesses in an > >> otherwise inactive/idle notebook. It seems to be about every 3 seconds > >> or so that the hard disk LED lights. This must make it impossible for > >> the hard drive to get powered down - and save power. > > I've gotten this request a few times now; I'll be looking into this for > > version 2.0; I'd think it would be possible with blktrace but I need to > > look into the details (don't want this tracing to spoil any other > > measurements ;) (cheers for the cc) > Just wondering: does Fedora spin down the hard disk by default? It > doesn't afaics and it's not easily user-configurable either afaik. It doesn't - you have to be very careful with the amount of power it takes to spin-up a drive (often significant) compared to the amount of time it's spun down. The amount of disk accesses is indeed horrific in a modern distro, and the drive doesn't usually spin down for long, even with laptop-mode flushing. This is bad. > Gnome-power-manager sounds like the proper place to control if the hard > disk gets powered down; but well, seem Richard got burned when he tried > it last time: Heh, burned is one word. :-) Unless we keep the disk from spinning up, my patch isn't actually that effective. I am however using a similar patch to HAL on my media center embedded PC, where I'm only running a pretty stripped system, and spin the disks down mostly for noise, not power saving. My view still is that this is a valid patch to HAL, and I would be quite happy to do the action automatically in g-p-m. I'm not sure we need UI - we can probably just profile the mean time that the disk is idle and work out if it is worth powering down. Ideas welcome. > See http://lists.freedesktop.org/archives/hal/2005-October/003538.html > and quoting from http://live.gnome.org/GnomePowerManager/FAQ : > ---- > GNOME Power Manager doesn't spin down my hard-drive! > > After numerous debates, the consensus was that is was not a good idea to > add this functionality to HAL. It's was decided user-configurable > powermanagement was not really required when modern hard disks have > really intelligent powermanagment. (I wrote this after numerous conversations with dannyk) True about the intelligent pm, although I still think we can make big savings if we do this carefully. > ...You can't set powermanagement for exteral USB > harddisks, because you can't send the needed commands over the USB link > to the disk. Can we still do this using libata? > So maybe this is not worth the trouble? I think it is - we are trimming easy stuff (like cpufreq and brightness) and I think we need to start looking at the drive spindown with a new vigour. Richard. (g-p-m dude) -- fedora-devel-list mailing list fedora-devel-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/fedora-devel-list
