Hi Paul, On Sun, May 12, 2013 at 04:31:57AM -0700, Paul E. McKenney wrote: > On Sat, May 11, 2013 at 08:04:50PM +0200, Bjørn Mork wrote: > > Bisecting it ended up pointing to > > > > commit c0f4dfd4f90f1667d234d21f15153ea09a2eaa66 > > Author: Paul E. McKenney <paul.mcken...@linaro.org> > > Date: Fri Dec 28 11:30:36 2012 -0800 > > > > rcu: Make RCU_FAST_NO_HZ take advantage of numbered callbacks > > > > Because RCU callbacks are now associated with the number of the grace > > period that they must wait for, CPUs can now take advance callbacks > > corresponding to grace periods that ended while a given CPU was in > > dyntick-idle mode. This eliminates the need to try forcing the RCU > > state machine while entering idle, thus reducing the CPU intensiveness > > of RCU_FAST_NO_HZ, which should increase its energy efficiency. > > > > Signed-off-by: Paul E. McKenney <paul.mcken...@linaro.org> > > Signed-off-by: Paul E. McKenney <paul...@linux.vnet.ibm.com> > > > > > > > > Being a big patch, I'm pretty sure that the problem is some minor > > issue. But rather than trying to userstand this, just tried reverting > > it on top of the current mainline and can confirm that this fixes the > > regression. I'll leave the understanding to you :) > > > > I'm attaching the revert patch as I had to fix a conflict, and may have > > done something wrong there. I'm also attaching my .config. > > > > Let me know if you need more information, or want me to try out proposed > > fixes. > > We don't want to back out the RCU_FAST_NO_HZ changes due to their > energy-efficiency benefits. So could you please try out Borislav's > patch below? He ran into the same issue a few weeks ago, and this > one fixed it for him.
I get a ~10min boot delay with this patch: [ 1.149676] system 00:01: [mem 0xf6000000-0xf6003fff] could not be reserved [ 1.149724] system 00:01: Plug and Play ACPI device, IDs PNP0c02 (active) [ 603.957670] pnp 00:02: [dma 4] [ 603.957735] pnp 00:02: Plug and Play ACPI device, IDs PNP0200 (active) This happens on my AMD FX-6100 system. I bisected the problem down to the same commit and reverting it fixes the problem. Any ideas? Joerg -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/