On 5 September 2014 14:06, Preeti U Murthy <pre...@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.guit...@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 > -- 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/