Scheduling of duplicate threads

A non-transitory computer readable storage medium having stored thereon a computer readable integrated circuit dataset description that, when processed in an integrated circuit manufacturing system, causes the integrated circuit manufacturing system to manufacture an integrated circuit embodying a processor comprising safety thread scheduling circuitry configured to schedule a check thread for a critical thread being run on one of a plurality of execution units, the check thread being a duplicate of the critical thread;

• the safety thread scheduling circuitry being configured to schedule the check thread to begin being run on a second one of the plurality of execution units before the end of a safety time-window for scheduling the check thread;
• and
• the safety thread scheduling circuitry being further configured to allow the check thread, when the check thread is running on the second one of the plurality of execution units, to be interrupted by a further thread and to re-schedule the check thread to be resumed by expiry of a re-scheduling time limit;
• wherein the safety thread scheduling circuit is operable to perform the re-scheduling of the check thread by interrupting another thread, other than the critical thread, running on one of the execution units other than the first execution unit, thereby resuming execution of the check thread on the execution unit upon which the other thread was running.

A method comprising:

• scheduling a check thread for a critical thread being run on one of a plurality of execution units, the check thread being a duplicate of the critical thread, wherein the scheduling of the check thread comprises scheduling the check thread to begin being run on a second one of the plurality of execution units before the end of a safety time-window for scheduling the check thread;
• and
• when the check thread is running on the second one of the plurality of execution units, interrupting the check thread by a further thread and re-scheduling the check thread to be resumed by expiry of a re-scheduling time limit;
• wherein the re-scheduling of the check thread comprises interrupting another thread, other than the critical thread, running on one of the execution units other than the first execution unit, thereby resuming execution of the check thread on the execution unit upon which the other thread was running.