lkml.org 
[lkml]   [2012]   [Jan]   [16]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [GIT PULL] tracing: make signal tracepoints more useful

    * Steven Rostedt <rostedt@goodmis.org> wrote:

    > On Mon, 2012-01-16 at 08:45 +0100, Ingo Molnar wrote:
    >
    > > Looks good to me at a first (quick) sight, except this bit
    > > which changes the ABI:
    > >
    > > > > - TP_printk("sig=%d errno=%d code=%d comm=%s pid=%d",
    > > > > + TP_printk("sig=%d errno=%d code=%d comm=%s pid=%d grp=%d res=%d",
    > >
    > > That's not how we change tracepoints generally - we add a new
    > > one and eventually phase out the old one. Which apps/tools rely
    > > on the old tracepoint? If it's exactly zero apps then we might
    > > be able to change it, but this needs to be investigated.
    >
    > But this tracepoint wasn't changed, it was added on to.
    > There's a difference. Any tool that uses this (including
    > something like powertop) should be able to handle it. [...]

    That's mostly true in theory - the question is, is it true in
    practice?

    Say if an app relies on the smaller data structure, it sure
    might get surprised by the kernel writing a wider record ...

    Thanks,

    Ingo


    \
     
     \ /
      Last update: 2012-01-16 13:57    [W:0.021 / U:31.004 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site