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Date:      Mon, 22 Oct 2007 16:02:56 +0800
From:      "Yi Wang" <wangyi6854@gmail.com>
To:        "Aryeh M. Friedman" <aryeh.friedman@gmail.com>
Cc:        Anish Mistry <mistry.7@osu.edu>, freebsd-stable@freebsd.org
Subject:   Re: X11 extremely slow while compiling other things
Message-ID:  <5ea5cca50710220102h30371d36qf47b13d0aa053356@mail.gmail.com>
In-Reply-To: <471C5136.40009@gmail.com>
References:  <5ea5cca50710202007p6081f44dyc4ca92a8917cdacf@mail.gmail.com> <200710211935.58020.mistry.7@osu.edu> <471C5136.40009@gmail.com>

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IPI_PREEMPTION allows the scheduler running on CPU A to preempt a thread
on CPU B. This should reduce latency in some circumstances.

# PREEMPTION allows the threads that are in the kernel to be preempted
#         by higher priority threads.  It helps with interactivity and
#         allows interrupt threads to run sooner rather than waiting.
#         WARNING! Only tested on amd64 and i386.
# FULL_PREEMPTION instructs the kernel to preempt non-realtime kernel
#         threads.  Its sole use is to expose race conditions and other
#         bugs during development.  Enabling this option will reduce
#         performance and increase the frequency of kernel panics by
#         design.  If you aren't sure that you need it then you don't.
#         Relies on the PREEMPTION option.  DON'T TURN THIS ON.


On 10/22/07, Aryeh M. Friedman <aryeh.friedman@gmail.com> wrote:
>
> > Try adding "options FULL_PREEMPTION" to your kernel.
> >
> >
> >
> What is the difference between this and PREEMPTION + IPI_PREEMPTION?
>


-- 
Regards,
Wang Yi



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