On 26/03/13 18:34, Mathieu Poirier wrote:
On 13-03-26 12:31 PM, Mathieu Poirier wrote:
On 13-03-26 11:27 AM, Viresh Kumar wrote:
On 26 March 2013 22:52, Dietmar Eggemann dietmar.eggemann@arm.com wrote:
Would it be possible for you to merge in 'idlenocb.2013.03.18b' (based on v3.9-rc2) (or newer) from 'git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git' into your big.LITTLE MP tree? I talked to Paul McKenney about this and he would like to have this additional test coverage.
13.03 release is already over and this would be available after that.
(2) On top of the merge, we must assure that the TC2 default config file gets changed:
Change the config file:
- Set CONFIG_RCU_FAST_NO_HZ=y
- Set CONFIG_RCU_NOCB_CPU=y
- Set CONFIG_RCU_NOCB_CPU_ALL=y
@Mathieu/Nicolas: you see any issues with these? I know we have been working on some issues with/without them for some time.
The CONFIG_RCU_FAST_NO_HZ option is known to increase the likely hood of hitting a tight race condition in the cpu hotplug and smpboot thread area. The condition doesn't disappear when the option is off but it decreases the failure rate.
Mathieu.
Hi Mathieu,
I ran an MP configuration based on the latest ll-20130325.0 branch from Linaro plus linux_paulmck_rcu/idlenocb.2013.03.26b with the RCU kernel configuration mentioned above.
I used pm-qa cpuhotplug_08.sh test against this system
# for i in $(seq 1000); do ./cpuhotplug_08.sh; done
and haven't encountered any issues. BTW, I'm not doing any IKS related tests.
-- Dietmar
What we could do is take it in 'next' and see how it behaves. After all the worst that can happen is to still observe the issue...
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