Hi,
I have run some tests to measure the improvement of the cpu plug duration with Tejun's patches. The results are available on this link: https://wiki.linaro.org/WorkingGroups/PowerManagement/Doc/Hotplug#Workqueue
As a summary, we can see a reduction of the plug sequence compared to the kernel v3.5 as kthreads are parked instead of being destroyed
Regards, Vincent
On 21 July 2012 19:24, Paul E. McKenney paulmck@linux.vnet.ibm.com wrote:
On Fri, Jul 20, 2012 at 02:14:46PM -0700, Paul E. McKenney wrote:
Hello!
Tejun just this week posted patches that park the workqueue kthreads, which should reduce CPU-online latency under load. The easiest way to get these patches appears to be to pull them from Tejun's git tree:
git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq.git review-wq-hotplug
They pass some extremely mild rcutorture/hotplug testing, and more testing will follow. Please take a look at these and give them a go.
And they pass moderate rcutorture/hotplug testing in a number of SMP configurations. The UP tests failed due to an apparently unrelated issue that I am chasing down.
Thanx, Paul