Intel has just been granted a patent that claims the rights to the concept of using initially inactive processing cores to replace failing cores.
According to the patent, increasingly complex processors with a greater number of cores, referred to as many-core processors by the company, will see higher failure rates than single- or dual-core processors. In fact, the patent states that the lifetime of a core may "shorten from generation to generation." The reasons include electromigration, stress migration, time dependent dielectric breakdown, negative bias temperature instability (NBTI), and thermal cycling.
To alleviate failure concerns, the patent covers an approach of core management, which is heavily focused on temperature monitoring of the individual cores: "Because many semiconductor failure mechanisms are expressed at elevated temperatures, temperature thus has a direct bearing on core MTTF [mean time to failure] and many-core reliability," the patent document explains. "If the temperature cannot be decreased, a many-core processor would activate spare cores to protect both the possibly failing core as well as neighboring cores. Both failed and spare cores are described to "absorb heat generated by active cores, driving the temperatures on the active cores down."
In an allocation/reallocation scenario, Intel says that the temperatures of cores can be drastically reduced.
There is no indication when Intel will actually use such a technology, but the examples in the patent start with at least 32 cores total, which use 16 active and 16 spare cores.