Let%27s delve into how the operating system (OS) manages DRAM (Dynamic Random-Access Memory):

1. Spatial Allocation:
- The OS allocates physical memory pages (page frames) to processes and manages their spatial distribution.
- Each page frame corresponds to a subset of the DRAM structure (channels, ranks, banks).

2. Admission Control:
- The OS must make informed decisions about which pages to admit into DRAM.
- It considers both spatial allocation and the underlying DRAM structure.
- An admission decision affects performance due to channel and bank dependencies¹.

3. Mapping Information:
- To optimize placement decisions, the OS needs knowledge of how physical addresses map to DRAM components.
- A standardized firmware interface describing this mapping can facilitate practical designs.

4. Performance Isolation:
- The OS can improve performance by controlling virtual memory-to-physical entity mappings.
- Ensuring efficient channel and bank utilization helps avoid interference among concurrent tasks¹.

In summary, the OS should treat DRAM as both a spatial resource and a processing resource, considering its complex hierarchy and optimizing admission decisions¹.
[^(Source)](https://os.itec.kit.edu/downloads/2017_Hillenbrand_Marius_Software_Defined_Physical_Memory_Putting_OS_in_Contorl_of_DRAM.pdf)

源: 与 Copilot 的对话， 2024/6/4
(1) Software-Defined Physical Memory: Putting The OS in Control of DRAM - KIT. https://os.itec.kit.edu/downloads/2017_Hillenbrand_Marius_Software_Defined_Physical_Memory_Putting_OS_in_Contorl_of_DRAM.pdf.
(2) DRAM REFRESH MANAGEMENT - University of Utah. https://users.cs.utah.edu/~bojnordi/classes/7810/s20/slides/12-memory.pdf.
(3) Understanding DRAM Architecture - IIT Kanpur. https://www.cse.iitk.ac.in/users/biswap/CASS18/CASS-DRAM-2018-NoAnim.pdf.
(4) A Comprehensive Approach to DRAM Power Management - University of Texas .... https://www.cs.utexas.edu/users/lin/papers/hpca08.pdf.

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