On Mon, Aug 22, 2011 at 10:11 PM, Vladimir Murzin <[email protected]>wrote:
> On Tue, Aug 23, 2011 at 2:15 AM, Vaibhav Jain <[email protected]> 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 <[email protected]> > > wrote: > >> > >> On Wed, Aug 17, 2011 at 11:01 PM, Vaibhav Jain <[email protected]> > 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 > >> > [email protected] > >> > 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. > >> > >> [1]http://en.wikipedia.org/wiki/Asymmetric_multiprocessing > > > > > > 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
_______________________________________________ Kernelnewbies mailing list [email protected] http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
