lkml.org 
[lkml]   [2006]   [Feb]   [21]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: make -j with j <= 4 seems to only load a single CPU core
    On 2/21/06, Paul Fulghum <paulkf@microgate.com> wrote:
    > On Tue, 2006-02-21 at 22:10 +0100, Jesper Juhl wrote:
    >
    > > I should probably mention that the kernel I'm currently running and
    > > observing this behaviour with is 2.6.16-rc4-mm1.
    > ...
    > > > I find this quite strange since anything from 'make -j 2' and up
    > > > should be able to keep both cores resonably busy, but there seems to
    > > > be a huge difference between j <= 4 and j > 4.
    >
    > I've seen the same thing (on Athlon 64x2 64 bit)
    > but was not sure if it was a problem.
    >
    > The break point for me seems to be between -j 2 and -j 3
    > -j 2 = serialized (or the appearance of)
    > -j 3 = both cores mostly busy
    >
    > I'm pretty sure with an earlier 2.6 kernel source (but same environment)
    > I did not see this. I'll start back tracking to earlier kernels
    > to see if I can identify when this started.
    >

    I know positively that I've seen this with previous 2.6.16-<something>
    kernels, but not sure which ones exactely. I just dismissed it as
    something that would probably be fixed soon and then today when I
    build a few test kernels I noticed it again and thought "ohh, so it
    didn't get fixed, better report it".

    I don't recall seeing it with 2.6.15 and earlier kernels, but I'm not
    at all sure - especially since I only got this Athlon X2 box recently
    and the first kernels I ever ran on it were 2.6.15-<something>.

    --
    Jesper Juhl <jesper.juhl@gmail.com>
    Don't top-post http://www.catb.org/~esr/jargon/html/T/top-post.html
    Plain text mails only, please http://www.expita.com/nomime.html
    -
    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: 2006-02-21 22:53    [W:3.139 / U:0.004 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site