Prime + Trigger + Probe
 demonstrates how to utilize the Prime + Probe technique to measure the cache activity, and extend it to the following Prime + Trigger + Probe measurement to support the setting of time-shared virtual machines.
- The probing instance first allocates a continuous buffer B of b bytes.
- Here b should be large enough that a significant portion of the cache is filled by B.
- Let s be the cache line size, in bytes.
- Then the probing instance performs the following steps to generate each load sample
- Prime: Read B at s-byte offset in order to ensure it is cached.
- Trigger: Busy-loop until the CPU’s cycle counter jump by a large value
- This means our VM was preempted by the Xen scheduler, hopefully in favor of the sender VM.
 Hey, You, Get Off of My Cloud: Exploring Information Leakage in Third-Party Compute Clouds, by Restenpart, T. et al., in CCS09