lkml.org 
[lkml]   [2019]   [Jan]   [31]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    From
    SubjectRe: [PATCH v4 01/10] sched: Provide sparsemask, a reduced contention bitmap
    Date
    On 12/6/18 1:28 PM, Steve Sistare wrote:
    > Provide struct sparsemask and functions to manipulate it. A sparsemask is
    > a sparse bitmap. It reduces cache contention vs the usual bitmap when many
    > threads concurrently set, clear, and visit elements, by reducing the number
    > of significant bits per cacheline. For each cacheline chunk of the mask,
    > only the first K bits of the first word are used, and the remaining bits
    > are ignored, where K is a creation time parameter. Thus a sparsemask that
    > can represent a set of N elements is approximately (N/K * CACHELINE) bytes
    > in size.
    >
    > This type is simpler and more efficient than the struct sbitmap used by
    > block drivers.
    >
    > Signed-off-by: Steve Sistare <steven.sistare@oracle.com>

    Steve,

    We did a test of this patch set with an OLTP benchmark using Oracle database
    on a 2 socket SKX platform with 2 X 28 cores. The patchset boosted the
    performance by 3.5%.

    The percentage of cpu idle time is lowered by 5%,
    with user time increased by 4% and kernel time increased by 1%,
    indicating a better cpu utilization overall.

    The performance looks encouraging.

    Thanks.

    Tim

    \
     
     \ /
      Last update: 2019-01-31 20:19    [W:2.778 / U:0.352 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site