Memory device, memory system including the memory device, and operating method of the memory system

A memory system comprising:

• a host;
• a first Compute Express Link CXL memory device including a first volatile memory that includes a first logical memory device, and a first CXL memory controller that is configured to control operations of the first volatile memory;
• and
• a CXL switch configured to provide an interface between the host and the first CXL memory device,
• wherein the host is configured to transmit first requests for the first volatile memory through the CXL switch,
• wherein the first logical memory device includes a plurality of segments that are physically separated from one another,
• wherein at least two of the plurality of segments form a single memory unit among a plurality of memory units of the first logical memory device,
• wherein the CXL switch comprises:
• a coarse-grained global counter configured to count a number of the first requests received for each of the plurality of memory units of the first logical memory device and store count values respectively associated with the number of the first requests received for each of the plurality of memory units;
• a global hotness monitor configured to determine, based on respective ones of the count values, whether each of the plurality of memory units of the first logical memory device is a hot unit or a cold unit;
• and
• a hotness tracker controller configured to generate a first bitmap for each of the plurality of memory units of the first logical memory device based on results of the determination of the global hotness monitor, and
• wherein the first CXL memory controller is configured to determine, based on the first bitmap, whether data stored in each of the plurality of segments included in the first logical memory device is hot, using a first hotness tracker.

An operating method of a memory system, comprising:

• providing a memory system including a host, a volatile memory that includes a logical memory device, a Compute Express Link CXL memory controller that is configured to control operations of the volatile memory, and a CXL switch that is configured to provide an interface between the host and the CXL memory controller;
• transmitting, by the host, requests for the volatile memory to the CXL memory controller through the CXL switch;
• counting, by a coarse-grained global counter, a number of the requests received for each of a plurality of memory units of the logical memory device and storing count values respectively associated with the number of the requests received for each of the plurality of memory units;
• determining, by a global hotness monitor, whether each of the plurality of memory units of the logical memory device is a hot unit or a cold unit based on respective ones the count values;
• generating, by a hotness tracker controller, a bitmap for each of the plurality of memory units of the logical memory device based on results of the determination of the global hotness monitor;
• and
• determining, by a hotness tracker, whether data stored in each of a plurality of segments included in the logical memory device is hot based on the bitmap,
• wherein each of the plurality of memory units includes at least two of the plurality of segments.