lkml.org 
[lkml]   [1999]   [Jul]   [18]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: kernel thread support - LWP's
    On Sun, Jul 18, 1999 at 08:25:51PM +0200, Ulrich Drepper wrote:
    > Andi Kleen <ak@muc.de> writes:
    >
    > > You send a signal back and do a sigwaitinfo() waiting for it. The signal
    > > can carry a status code.
    >
    > Using yet another signal and system calls? Everybody is complaining
    > that the thread creation is so much slower than a simple clone() but
    > when I explain what I need people do not even listen. You've seen the

    Sending SIGSTP or a unrelated signal have near the same cost.

    Similar waitpid for a STOP and sigwaitinfo.

    It depends on what you find more important:
    latency from creation to child run [sigqueueinfo/sigwaitinfo have a slight advantage
    here because it can simply run through without caring about the parent]
    or
    latency from calling pthread_create to its return [SIGSTP/waitpid may be better here,
    because the final thread restart is decoupled from the caller]
    On UP it probably makes not much difference because one CPU has to do all the work
    anyways, on SMP it may look different.

    > code I've orignially posted, The code size increase in the kernel is
    > minial. What can possibly be wrong with this?

    What I didn't like with your idea is that it is 100% equivalent (even from the
    work the kernel has to do) to kill(getpid(), SIGSTP); at the beginning
    of the child.


    -Andi

    --
    This is like TV. I don't like TV.

    -
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.rutgers.edu
    Please read the FAQ at http://www.tux.org/lkml/

    \
     
     \ /
      Last update: 2005-03-22 13:53    [W:2.319 / U:0.016 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site