Dynamic timing for shutdown including asynchronous dynamic random access memory refresh (ADR) due to AC undervoltage

A controller, comprising:

• a processing resource;
• and
• a memory in communication with the processing resource and encoded with instructions that, when executed by the processing resource, perform a method including:
• detecting an alternating current (“AC”) undervoltage condition in a compute system by
• receiving a first indication from each of a plurality of power supplies for the compute system whether the respective power supply is receiving an input power within regulation;
• receiving a second indication from each of the plurality of power supplies whether the respective power supply is providing an output power within regulation;
• comparing the number of negative first indications to the number of positive second indications;
• if a number of negative first indications matches a number of positive second indications, then determining that the AC undervoltage condition persists;
• and
• if the number negative first indications is less than the number of positive second indications, then determining that the AC undervoltage condition has resolved;
• and
• in response to detecting the AC undervoltage condition:
• dynamically determining a holdup time, including:
• determining a present load for the plurality of power supplies, the present load comprising the amount of power presently being drawn from the plurality of power supplies characterized as a percentage of a rated load for the plurality of power supplies;
• ascertaining the holdup time for the compute system as a function of the present load;
• determining a monitoring period as a function of the dynamically determined holdup time;
• waiting for the determined monitoring period;
• and
• in response to expiration of the determined monitoring period, performing a shutdown process if the AC undervoltage condition persists.

A compute system, comprising:

• a plurality of computational nodes;
• a power subsystem receiving an alternating current (“AC”) power input and including a plurality of power supplies providing power to the computational nodes;
• and
• a controller including:
• a processing resource;
• and
• a memory encoded with instructions that, when executed by the processing resource, perform a method including:
• detecting an AC undervoltage condition in the compute system by
• receiving a first indication from each of a plurality of power supplies for the compute system whether the respective power supply is receiving an input power within regulation;
• receiving a second indication from each of the plurality of power supplies whether the respective power supply is providing an output power within regulation;
• comparing the number of negative first indications to the number of positive second indications;
• if a number of negative first indications matches a number of positive second indications, then determining that the AC undervoltage condition persists;
• and
• if the number of negative first indications is less than the number of positive second indications, then determining that the AC undervoltage condition has resolved;
• and
• in response to detecting the AC undervoltage condition:
• dynamically determining a holdup time, including:
• determining a present load for a plurality of power supplies, the present load comprising the amount of power presently being drawn from the plurality of power supplies characterized as a percentage of a rated load for the plurality of power supplies;
• ascertaining the holdup time for the compute system as a function of the present load;
• determining a monitoring period as a function of the determined holdup time;
• waiting for the determined monitoring period;
• and
• in response to expiration of the determined monitoring period, perform a shutdown process if the AC undervoltage condition persists.