Please, put 64-bit counter per task and incr.by.one each ctxt switch.

["J.C. Pizarro" <jcpiza@gmail.com>]

Hello,

We will need 64 bit counters of the slow context switches,
  one counter for each new created task (e.g. u64 ctxt_switch_counts;)

We will only need them during the lifetime of the tasks.

To increment by +1 the task's 64 bit counter (it's fast)
  each one slow context switch.

*kernel/sched.c:
void context_switch(...) { ... } # incr. +1 here.
void wake_up_new_task(...) { ... } # ->ctxt_switch_counts = 0ULL;

*include/linux/sched.h:
struct task_struct { ... } # add 64-bit (u64 ctxt_switch_counts;) here.

Please, do it and we can do it better than CFS fair scheduler.

I will explain your later why of it.

   O:)