multithreading - Sleep a long running process -

i have app iterates on tens of thousands of records using various enumerators (such directory enumerators)

i seeing os x saying process "caught burning cpu" since taking large amount of cpu in doing so.

what build in "pressure valve" such a

[nsthread sleepfortimeinterval:cpudelay]; 

that not block other processes/threads on things dual core machine.

my processing happening on separate thread, can't break out of , re-enter enumerator loop , use nstimers allow machine "breathe"

any suggestions - should [nsthread sleepfortimeinterval:cpudelay]; working?

i run stuff inside dispatch queue:

if(!primarytask)primarytask=dispatch_queue_create(          "com.me.app.task1",backgroundpriorityattr);   dispatch_async(primarytask,^{             [self dosync];         }); 

try wrapping processing in nsoperation , set lower qos priority. here little more information: http://nshipster.com/nsoperation/

here code example made up. operation triggered in view load event:

    let processingqueue = nsoperationqueue()  override func viewdidload() {      let backgroundoperation = nsblockoperation {         //my long , intesive processing         let npoints = 100000000000          var npointsinside = 0          _ in 1...npoints {             let (x, y) = (drand48() * 2 - 1, drand48() * 2 - 1)             if x * x + y * y <= 1 {                 npointsinside += 1             }         }          let _ = 4.0 * double(npointsinside) / double(npoints)     }      backgroundoperation.queuepriority = .low     backgroundoperation.qualityofservice = .background      processingqueue.addoperation(backgroundoperation) }