System and method for controlling cache flush size

An information handling system, comprising:

• at least one cache;
• and
• a cache controller comprising circuitry to:
• store a threshold value for modified cache lines in a cache, the threshold value being dependent on one or more of:
• available hold-up energy in the system and an amount of time needed to flush modified cache lines to persistent memory;
• detect a write to a cache line in the cache;
• determine whether or not the write causes the cache line to transition to a modified state;
• in response to a determination that that the write causes the cache line to transition to the modified state:
• increment a count of modified cache lines in the cache;
• determine, dependent on the incremented count, whether or not the threshold value is exceeded;
• flush one or more modified cache lines in the cache to the persistent memory, in response to a determination that the threshold value is exceeded, the flushing including transitioning the one or more modified cache lines from the modified state to a state other than the modified state;
• and
• elide a flush of the one or more modified cache lines in the cache to persistent memory, in response to a determination that the threshold value is not exceeded.

A cache controller, comprising circuitry to:

• store a threshold value for modified cache lines in a cache, the threshold value being dependent on one or more of:
• hold-up energy available from a back-up energy source and an amount of time needed to flush modified cache lines to persistent memory;
• detect a write to a cache line in the cache;
• determine whether or not the write causes the cache line to transition to a modified state;
• in response to a determination that that the write causes the cache line to transition to the modified state:
• increment a count of modified cache lines in the cache;
• determine, dependent on the incremented count, whether or not the threshold value is exceeded;
• flush one or more modified cache lines in the cache to the persistent memory, in response to a determination that the threshold value is exceeded, the flushing including transitioning the one or more modified cache lines from the modified state to a state other than the modified state;
• and
• elide a flush of the one or more modified cache lines in the cache to persistent memory, in response to a determination that the threshold value is not exceeded.