lkml.org 
[lkml]   [2019]   [Jan]   [28]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [PATCH AUTOSEL 4.20 163/304] sched/topology: Add lowest CPU asymmetry sched_domain level pointer
    On Mon, Jan 28, 2019 at 04:14:17PM +0000, Quentin Perret wrote:
    >Hi Sasha,
    >
    >On Monday 28 Jan 2019 at 10:41:20 (-0500), Sasha Levin wrote:
    >> From: Quentin Perret <quentin.perret@arm.com>
    >>
    >> [ Upstream commit 011b27bb5d3139e8b5fe9ceff1fc7f6dc3145071 ]
    >>
    >> Add another member to the family of per-cpu sched_domain shortcut
    >> pointers. This one, sd_asym_cpucapacity, points to the lowest level
    >> at which the SD_ASYM_CPUCAPACITY flag is set. While at it, rename the
    >> sd_asym shortcut to sd_asym_packing to avoid confusions.
    >>
    >> Generally speaking, the largest opportunity to save energy via
    >> scheduling comes from a smarter exploitation of heterogeneous platforms
    >> (i.e. big.LITTLE). Consequently, the sd_asym_cpucapacity shortcut will
    >> be used at first as the lowest domain where Energy-Aware Scheduling
    >> (EAS) should be applied. For example, it is possible to apply EAS within
    >> a socket on a multi-socket system, as long as each socket has an
    >> asymmetric topology. Energy-aware cross-sockets wake-up balancing will
    >> only happen when the system is over-utilized, or this_cpu and prev_cpu
    >> are in different sockets.
    >
    >Although I'm not really confident about the process for those AUTOSEL
    >patches, I think this one alone won't help anybody without the other ~10
    >EAS patches. And I assume you definitely don't want to mark those as
    >stable, so I'm not sure if this one is a good candidate either.

    I'll drop it then, thanks for the heads-up.

    >On a side note, the best description I could find of AUTOSEL with a
    >5 min Google search is this: https://lwn.net/Articles/750057/
    >Do you have any pointers to a doc where I can read up about AUTOSEL ?

    For written material, this is based on Julia Lawall's work:
    https://soarsmu.github.io/papers/icse12-patch.pdf .

    We did a talk last year which is more recent than the paper:
    https://www.youtube.com/watch?v=KWholDv6-Rw .

    --
    Thanks,
    Sasha

    \
     
     \ /
      Last update: 2019-01-28 18:19    [W:4.233 / U:0.204 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site