Re: Scheduler: SIGSTOP on multi threaded processes

["Richard B. Johnson" <linux-os@analogic.com>]

On Wed, 4 May 2005, linux-os (Dick Johnson) wrote:

> On Wed, 4 May 2005, Daniel Jacobowitz wrote:
>
> > On Wed, May 04, 2005 at 02:16:24PM -0400, Richard B. Johnson wrote:
> > > The kernel doesn't do SIGSTOP or SIGCONT. Within init, there is
> > > a SIGSTOP and SIGCONT handler. These can be inherited by others
> > > unless changed, perhaps by a 'C' runtime library. Basically,
> > > the SIGSTOP handler executes pause() until the SIGCONT signal
> > > is received.
> > >
> > > Any delay in stopping is the time necessary for the signal to
> > > be delivered. It is possible that the section of code that
> > > contains the STOP/CONT handler was paged out and needs to be
> > > paged in before the signal can be delivered.
> > >
> > > You might quicken this up by installing your own handler for
> > > SIGSTOP and SIGCONT....
> >
> > I don't know what RTOSes you've been working with recently, but none of
> > the above is true for Linux.  I don't think it ever has been.
> >
> > --
> > Daniel Jacobowitz
> > CodeSourcery, LLC
>
> Grab a copy of your favorite init source. SIGSTOP and SIGCONT are
> signals. They are handled by signal handlers, always have been
> on Unix and Unix clones like Linux.

Sorry. I thought he was talking about SIGTSTP and SIGCONT, the
X-ON X-OFF signals. I thought he was sending a SIGTSTP signal
to a task, timing it, then continuing with SIGCONT. He said that
it didn't operate fast enought.

Cheers,
Dick Johnson
Penguin : Linux version 2.6.11 on an i686 machine (5537.79 BogoMips).
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