On Mon, Aug 22, 2011 at 10:11 PM, Vladimir Murzin <murzin.v@gmail.com>wrote:
On Tue, Aug 23, 2011 at 2:15 AM, Vaibhav Jain <vjoss197@gmail.com> wrote:
Hi, Thanks for replying but I want to do this in a SMP machine. Please help!
Thanks Vaibhav Jain
On Wed, Aug 17, 2011 at 10:53 PM, Vladimir Murzin <murzin.v@gmail.com> wrote:
On Wed, Aug 17, 2011 at 11:01 PM, Vaibhav Jain <vjoss197@gmail.com>
wrote:
Hi,
I am looking into running a program on one of the cores which is isolated (logically offline ) from the rest of the cores. I have come to that the command echo 0 > /sys/device/system/cpu/<core num>/online
will make a core logically offline, What I need to do now is to run a program on this offline core. Please suggest on how to proceed.
Thanks! Vaibhav Jain _______________________________________________ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Hi Vaibhav,
I think it's impossible to run out a process on unplugged CPU. May be AMP[1] is what you need, but it's a bit different approach.
Hi Vaibhav,
There is one more approach, but it's not operate on off-lined CPU. Have a look at isolcpu kernel boot option. Description in Documentation/kernel-parameters.txt says:
This option can be used to specify one or more CPUs to isolate from the general SMP balancing and scheduling algorithms. You can move a process onto or off an "isolated" CPU via the CPU affinity syscalls or cpuset. <cpu number> begins at 0 and the maximum value is "number of CPUs in system - 1". This option is the preferred way to isolate CPUs. The alternative -- manually setting the CPU mask of all tasks in the system -- can cause problems and suboptimal load balancer performance.
Hi, Thanks again! But I am asked to look into running process only when the cpu has been logically offlined. Someone suggested that I should make changes to arch/x_86/kernel/smpboot.c file in one of the play_dead functions. But I don't know what these function is doing and what changes should I make. Could you please give me some idea ? Thanks Vaibhav Jain