Messages in this thread | | | Date | Mon, 16 Nov 2015 15:15:03 -0800 | From | Jacob Pan <> | Subject | Re: [PATCH 2/4] timer: relax tick stop in idle entry |
| |
On Mon, 16 Nov 2015 14:31:17 -0800 "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> wrote:
> > Either one works but my concern is that users may not realize the > > intricate CONFIG_ options and how they translate into energy > > savings. Consulted with Josh, it seems we could add a check here to > > recognize the forced idle state and relax rcu_needs_cpu() to return > > false even it has callbacks. Since we are blocking everybody for a > > short time (5 ticks default). It should not impact synchronize and > > kfree rcu. > > Or we could just set things up so that whatever Kconfig you are using > to enable this state causes CONFIG_RCU_NOCB_CPU_ALL to also be > enabled. Or that causes CONFIG_RCU_FAST_NO_HZ to also be enabled, if > that works better for you. That would be great, we can work this out once the patch is finalized. This is not a hard dependency in that it only affects the efficiency of idle injection.
| |