[EMAIL PROTECTED] wrote on Tue, 06 Jun 2006 16:23 -0500:
> Thus spake Pete Wyckoff:
> > [EMAIL PROTECTED] wrote on Mon, 05 Jun 2006 10:53 -0500:
> > > Pete, I think you're on to something! Adding the sched_yield() call to
> > > the BMI_ib_testcontext() function has sped things up tremendously. In
> > > addition, pvfs2-server now only shows 10% CPU usage (and not for nearly
> > > as long as previously) in top when doing the pvfs2-mkdir command.
>
> Of course, in 2.6 kernels, use of sched_yield() means that you may end
> up sleeping a long time, and could be asking for trouble...
>
> - The behavior of sched_yield() changed a lot. A task that uses
> this system call should now expect to sleep for possibly a very
> long time. Tasks that do not really desire to give up the
> processor for a while should probably not make heavy use of this
> function. Unfortunately, some GUI programs (like Open Office)
> do make excessive use of this call and under load their
> performance is poor. It seems this new 2.6 behavior is optimal
> but some user-space applications may need fixing.
Thanks, I vaguely recall that being a bad idea. I'll keep it out of
the production source. At some point we can have Lee test
event-driven rather than polling bmi_ib, as it seems we can't trust
the thread scheduler to make sure everything makes progress, at
least on that particular kernel.
-- Pete
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