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]> -- ~Randy -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
