Primitives to enhance thread-level speculation

A method, comprising:

• executing an update control register user-level instruction to update a control register associated with a speculative thread of a processor to hold a monitor value;
• executing with the speculative thread a memory instruction;
• monitoring the memory instruction in response to the control register associated with the speculative thread holding the monitor value;
• and
• not monitoring the memory instruction in response to the control register holding an unmonitored value.

A method, comprising:

• concurrently executing a plurality of threads that share a common logical view of memory;
• suspending execution of all but a first one of the threads in order to allow the first thread to execute a block of instructions atomically;
• wherein said suspending is triggered by action of the first thread to invoke a hardware mechanism;
• and
• resuming the other threads after the first thread has completed atomic execution of the block of instructions.