On Mon, Apr 14, 2014 at 05:12:08PM +0530, Viresh Kumar wrote:
On 14 April 2014 16:32, Peter Zijlstra peterz@infradead.org wrote:
I'm still not sure _what_ you're trying to solve here. What are you doing and why?
Hi Peter,
We are working building ARM Networking machines. Networking Data plane is handled completely at user space. At run time we may fix any number of CPUs for data plane activities. There will be a single user space thread per CPU for these data plane packet processing. Due to timing constraints these cores can't allow any interruption from kernel. These include interruption from:
- other tasks: Fixed with cpusets
- timers/hrtimers: Implemented cpuset.quiesce as you suggested:
Waiting for reviews
- workqueues: Probably would be fixed by Frederic's work.
Ok.
- Tick: Even with NO_HZ_FULL we get a tick every second. This is
what I am trying to address here. Frederic earlier suggested to offload this accounting to other CPUs and so was my initial proposal.
What causes this tick? I was under the impression that once there's a single task (not doing any syscalls) and the above issues are sorted, no more tick would happen.