On Thu, Apr 11, 2013 at 01:09:28PM -0700, Randy Dunlap wrote:
> On 04/11/13 11:40, Paul E. McKenney wrote:
> > On Thu, Apr 11, 2013 at 10:18:26AM -0700, Randy Dunlap wrote:
> >> On 04/11/2013 09:05 AM, Paul E. McKenney wrote:
> >>> From: "Paul E. McKenney" <[email protected]>
> >>>
> >>> The Linux kernel uses a number of per-CPU kthreads, any of which might
> >>> contribute to OS jitter at any time. The usual approach to normal
> >>> kthreads, namely to affinity them to a "housekeeping" CPU, does not
> >>
> >> ugh. to affine them
> >
> > How about s/affinity/bind/ instead?
>
> Yes, that's good.
>
> >>> work with these kthreads because they cannot operate correctly if moved
> >>> to some other CPU. This commit therefore lists ways of controlling OS
> >>> jitter from the Linux kernel's per-CPU kthreads.
> >>>
> >>> Signed-off-by: Paul E. McKenney <[email protected]>
> >>> Cc: Frederic Weisbecker <[email protected]>
> >>> Cc: Steven Rostedt <[email protected]>
> >>> Cc: Borislav Petkov <[email protected]>
> >>> Cc: Arjan van de Ven <[email protected]>
> >>> Cc: Kevin Hilman <[email protected]>
> >>> Cc: Christoph Lameter <[email protected]>
> >>> ---
> >>> Documentation/kernel-per-CPU-kthreads.txt | 159
> >>> ++++++++++++++++++++++++++++++
> >>> 1 file changed, 159 insertions(+)
> >>> create mode 100644 Documentation/kernel-per-CPU-kthreads.txt
> >>>
> >>> diff --git a/Documentation/kernel-per-CPU-kthreads.txt
> >>> b/Documentation/kernel-per-CPU-kthreads.txt
> >>> new file mode 100644
> >>> index 0000000..495dacf
> >>> --- /dev/null
> >>> +++ b/Documentation/kernel-per-CPU-kthreads.txt
> >>> @@ -0,0 +1,159 @@
> >>> +REDUCING OS JITTER DUE TO PER-CPU KTHREADS
> >>> +
> >>> +
> >>> +Name: irq/%d-%s
> >>> +Purpose: Handle threaded interrupts.
> >>> +To reduce corresponding OS jitter, do the following:
> >>> +1. Use irq affinity to force the irq threads to execute on
> >>> + some other CPU.
> >>
> >> It would be very nice to explain here how that is done.
> >
> > Documentation/IRQ-affinity.txt
> >
> > I added a pointer to this near the beginning.
> >
>
> Good.
>
> > Thank you for your review and comments! Given my rationale above,
> > are you still comfortable with my applying your Reviewed-by?
>
> Sure. Thanks.
>
> >> Reviewed-by: Randy Dunlap <[email protected]>
I have added your Reviewed-by, thank you again!
Thanx, Paul
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