revert commit f0e6dc6304; overload detection logic was fine already

revert commit f0e6dc6304; overload detection logic was fine already

btw, here's a test script to monitor the persistent context values:

function cycles(which:long) %{
        THIS->__retvalue = (THIS->which == 0) ? CONTEXT->cycles_base :
                                                CONTEXT->cycles_sum;
%}

probe timer.profile { /* just for */ backtrace() /* load generation */
                      printf("%d %d\n", cycles(0), cycles(1)) }
probe timer.s(1) { exit() }