Thanks Wojciech for the quick reply. I read about rcu offloading and in my testing, can confirm that kernel rcu threads are scheduled on core 0 even if core 0 is isolated. Another thing I observed was that there are some kworker threads which run on isolated cpus other than 0. Is this expected behavior, because I used to think that isolated cpus are not touched by the kernel. These kworker threads will definitely lead to context switches and hamper performance a little bit. And I am afraid we can do nothing to get rid of them.
Himanshu Sharma On Mon, May 22, 2017 at 2:08 PM, Wojciech Kudla <wojciech.ku...@gmail.com> wrote: > There's a number of kernel tasks that are implicitly bound to cpu0. For an > example of one have a look at rcu offloading and its restrictions. > > On Mon, 22 May 2017, 08:59 Himanshu Sharma, <imhimansh...@gmail.com> > wrote: > >> Hi Michael >> >> Did you find a satisfactory reason for not isolating cpu 0, maybe some >> low level OS code that is bound to run on core 0? I am also stuck at this >> question right now and am thinking you might have an answer. >> >> Thanks >> Himanshu >> >> On Wednesday, March 4, 2015 at 8:08:22 PM UTC+5:30, Michael Mattoss wrote: >>> >>> Hi guys, >>> >>> I'm in the process of setting up a new dual-socket server for a low >>> latency workload. >>> The application will run exclusively on one CPU and everything else >>> (i.e. OS, non-critical processes) will run on the other CPU to avoid cache >>> pollution. >>> I was wondering if it makes any difference as to which one of the >>> 2 CPU's is chosen for the workload. >>> Theoretically, there should be no difference but I was wondering if >>> there is some low-level stuff (e.g. core OS code, system management >>> interrupts handlers) that is statically allocated to CPU-0 as every system >>> has at least 1 CPU. >>> Of course, if that's the case then CPU-1 is the better choice. >>> >>> Any thoughts/suggestions? >>> >>> Thanks, >>> Michael >>> >> -- >> You received this message because you are subscribed to the Google Groups >> "mechanical-sympathy" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to mechanical-sympathy+unsubscr...@googlegroups.com. >> For more options, visit https://groups.google.com/d/optout. >> > -- > You received this message because you are subscribed to a topic in the > Google Groups "mechanical-sympathy" group. > To unsubscribe from this topic, visit https://groups.google.com/d/ > topic/mechanical-sympathy/SnJ6LTKCjEU/unsubscribe. > To unsubscribe from this group and all its topics, send an email to > mechanical-sympathy+unsubscr...@googlegroups.com. > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "mechanical-sympathy" group. To unsubscribe from this group and stop receiving emails from it, send an email to mechanical-sympathy+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
