lkml.org 
[lkml]   [2010]   [Jun]   [3]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    SubjectRe: [linux-pm] [PATCH 0/8] Suspend block api (version 8)
    From
    Date
    On Thu, 2010-06-03 at 00:10 -0700, Arve Hjønnevåg wrote:
    > On Wed, Jun 2, 2010 at 10:40 PM, mark gross <640e9920@gmail.com> wrote:
    > > On Wed, Jun 02, 2010 at 09:54:15PM -0700, Brian Swetland wrote:
    > >> On Wed, Jun 2, 2010 at 8:18 PM, mark gross <640e9920@gmail.com> wrote:
    > >> > On Wed, Jun 02, 2010 at 02:58:30PM -0700, Arve Hjønnevåg wrote:
    > >> >>
    > >> >> The list is not short. You have all the inactive and active
    > >> >> constraints on the same list. If you change it to a two level list
    > >> >> though, the list of unique values (which is the list you have to walk)
    > >> >> may be short enough for a tree to be overkill.
    > >> >
    > >> > what have you seen in practice from the wake-lock stats?
    > >> >
    > >> > I'm having a hard time seeing where you could get more than just a
    > >> > handfull. However; one could go to a dual list (like the scheduler) and
    > >> > move inactive nodes from an active to inactive list, or we could simply
    > >> > remove them from the list uppon inactivity. which would would well
    > >> > after I change the api to have the client allocate the memory for the
    > >> > nodes... BUT, if your moving things in and out of a list a lot, I'm not
    > >> > sure the break even point where changing the structure helps.
    > >> >
    > >> > We'll need to try it.
    > >> >
    > >> > I think we will almost never see more than 10 list elements.
    > >> >
    > >> > --mgross
    > >> >
    > >> >
    > >>
    > >> I see about 80 (based on the batteryinfo dump) on my Nexus One
    > >> (QSD8250, Android Froyo):
    > >
    > > shucks.
    > >
    > > well I think for a pm_qos class that has boolean dynamic range we can
    > > get away with not walking the list on every request update. we can use
    > > a counter, and the list will be for mostly for stats.
    > >
    >
    > Did you give any thought to my suggestion to only use one entry per
    > unique value on the first level list and then use secondary lists of
    > identical values. That way if you only have two constraints values the
    > list you have to walk when updating a request will never have more
    > than two entries regardless of how many total request you have.
    >
    > A request update then becomes something like this:
    > if on primary list {
    > unlink from primary list
    > if secondary list is not empty
    > get next secondary entry and add in same spot on primary list
    > }
    > unlink from secondary list
    > find new spot on primary list
    > if already there
    > add to secondary list
    > else
    > add to primary list

    This is just reinventing hash bucketed lists. To get the benefits, all
    we do is implement an N state constraint as backed by an N bucketed hash
    list, which the kernel already has all the internal mechanics for.

    James


    --
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/

    \
     
     \ /
      Last update: 2010-06-03 16:39    [W:0.025 / U:32.528 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site