Incorrect Density for HBM2_8Gb Preset in Memory Configuration

[Ozen7]

ramulator2/src/dram/impl/HBM2.cpp

Line 14 in e62c84a

{"HBM2_8Gb", {6<<10, 128, {1, 2, 4, 4, 1<<15, 1<<6}}},

Hello,

The HBM2_8Gb preset defines a density of 6<<10 (6144 Mb or 6 Gb) per channel. However, the preset name (HBM2_8Gb) suggests the density should be 8<<10 (8192 Mb or 8 Gb) per channel. This mismatch leads to errors when using this preset in configurations expecting 8 Gb density.

Steps to Reproduce

1. Configure Ramulator with the following setup:

DRAM:
  impl: HBM2
  org:
    preset: HBM2_8Gb
    channel: 8
    rank: 1
  timing:
    preset: HBM2_2000

2. Run a simulation with this configuration.
3. Observe the error indicating a mismatch between the calculated density and the preset density:
   An error occurred: Calculated HBM2 channel density 8192 Mb does not equal the provided density 6144 Mb!

Expected Behavior

The HBM2_8Gb preset should define a density of 8<<10 (8192 Mb) per channel, matching the preset name.

Thank you!

[Ozen7]

Also, out of pure curiosity, can HBM be used with a closed-row policy? I realize it doesn't make much sense from a real-world use perspective, but I was wondering if it was at all possible.

For reference, the configuration errors out when you try to implement this since the closed-row policy requires a rank from the memory implementation (and HBM of course doesn't have one).

ramulator2/src/dram_controller/impl/rowpolicy/basic_rowpolicies.cpp

Line 56 in e62c84a

m_rank_level = m_dram->m_levels("rank");