2014 and prior -- Analysis of the need for, planning, and execution of layoff was an ordeal, with the 6+ months span fully visible to the employee base
2015 Q2 -- The time from when layoff rumors surfaced in the Oregonian through the stealth announcements to execution completion was a little over one month
2016 Q2 -- No word of (mass) layoffs appeared until the Q1 results meeting in mid-April. A week and a half later, in completing one of Intel's slimiest actions ever, several thousand employees had been perp-walked out the door.
~6 months to ~1 month to a week and a half -- sadly this is the only area within Intel where Moore's Law is still alive. One has to wonder what the next "process efficiency improvement" in this space will deliver.