On 5 September 2014 14:06, Preeti U Murthy preeti@linux.vnet.ibm.com wrote:
Hi Vincent,
On 08/26/2014 04:36 PM, Vincent Guittot wrote:
If the CPU is used for handling lot of IRQs, trig a load balance to check if it's worth moving its tasks on another CPU that has more capacity.
As a sidenote, this will note generate more spurious ilb because we already trig an ilb if there is more than 1 busy cpu. If this cpu is the only one that has a task, we will trig the ilb once for migrating the task.
The nohz_kick_needed function has been cleaned up a bit while adding the new test
Signed-off-by: Vincent Guittot vincent.guittot@linaro.org
So I see that there are added checks in your previous patches on if the cpu capacity for CFS tasks is good enough to run tasks on the cpu. My concern is although they appear sensible, would they trigger an increase in the number of times we load balance to a large extent.
Ebizzy would not test this aspect right? There are no real time tasks/interrupts that get generated.
yes, ebizzy doesn't test this part but check for non regression
The scp test is the one that i use to check this patch and the previous one but a test with some cfs and rt tasks should also do the jobs. we can see an increase of 82% for the dual core when CONFIG_IRQ_TIME_ACCOUNTING is enable
Besides, what is the column that says patchset+irq? What is the irq accounting patchset that you refer to in your cover letter?
it refers to CONFIG_IRQ_TIME_ACCOUNTING which includes the time spent under interrupt context to compute the scale_rt_capacity
Regards, Vincent
Regards Preeti U Murthy