lkml.org 
[lkml]   [2010]   [Jan]   [7]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    SubjectRe: [RFC PATCH] introduce sys_membarrier(): process-wide memory barrier
    From
    Date
    On Thu, 2010-01-07 at 01:19 -0500, Mathieu Desnoyers wrote:

    > I see your point.

    Actually you are missing the point ;-)

    >
    > This would probably be good for machines with very large number of cpus
    > and without IPI broadcast support, running processes with only few
    > threads. I really start to think that we should have some way to compare
    > the number of threads belonging to a process and choose between the
    > broadcast IPI and the per-cpu IPI depending if we are over or under an
    > arbitrary threshold.


    This has nothing to do with performance. It has to do with a thread
    should not interfere with a thread belonging to another process. We
    really don't care how long the sys_membarrier() takes (it's the slow
    path anyway). We do care that a critical RT task is being interrupted by
    some java thread sending thousands of IPIs.

    -- Steve




    \
     
     \ /
      Last update: 2010-01-07 15:29    [W:3.675 / U:0.396 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site