configs: Initialize classic L2 DRRIP slice params

[jensen-yan]

Summary

Initialize DRRIP slice-related parameters for the classic-L2 configuration.

Problem

The default L2 cache uses DRRIPRP, which inherits from DuelingRP. In the classic-L2 configuration, the replacement policy did not initialize num_slices and num_sets_per_slice.

As a result, the simulator could hit floorLog2(0) during initialization and abort at tick 0 when running with --classic-l2.

Fix

When classic L2 is configured, initialize the DRRIP replacement policy with:

• num_slices = 1
• num_sets_per_slice = size / (64 * assoc)

This keeps the classic-L2 configuration consistent with the assumptions made by the replacement-policy implementation.

Validation

Validated with SE matrix tests using --classic-l2:

• precomp_rand_repro: passes
• gemm_precomp: all 8 precomputed cases pass

[coderabbitai]

📝 Walkthrough

Walkthrough

The L2 cache configuration now conditionally customizes replacement policy parameters when using DRRIPRP instances, setting num_slices to 1 and deriving num_sets_per_slice from the cache's size and associativity using a fixed divisor.

Changes

Cohort / File(s)	Summary
Cache Configuration Customization configs/common/CacheConfig.py	Adds conditional logic to customize DRRIPRP replacement policy parameters in L2 cache config, setting num_slices to 1 and computing num_sets_per_slice from cache size and associativity.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~8 minutes

Poem

🐰 A whisker-twitch of cache delight,
With slices set just right, so tight,
DRRIPRP now knows its place,
In configs where the L2 race,
Hops faster through the memory space! ✨

🚥 Pre-merge checks | ✅ 2 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title accurately summarizes the main change: it specifies that DRRIP slice parameters are being initialized in the classic L2 cache configuration.
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.

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✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch fix-classic-l2-drrip-config

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[chatgpt-codex-connector]

💡 Codex Review

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Reviewed commit: 64ea8a148c

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[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Inline comments:
In `@configs/common/CacheConfig.py`:
- Around line 95-98: DRRIP set geometry currently hardcodes a 64B line size;
update the computation in the DRRIPRP block
(system.l2_caches[i].replacement_policy) so num_sets_per_slice =
system.l2_caches[i].size // (system.cache_line_size * system.l2_caches[i].assoc)
(use system.cache_line_size rather than 64), and defensively fall back to 64 if
system.cache_line_size is missing/None; keep other assignments to num_slices and
num_sets_per_slice unchanged.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

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ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: a35af615-1370-45c4-a3c1-81c96d55e949

📥 Commits

Reviewing files that changed from the base of the PR and between 86825b3 and 64ea8a1.

📒 Files selected for processing (1)

• configs/common/CacheConfig.py

[github-actions]

🚀 Coremark Smoke Test Results

Branch	IPC	Change
Base (xs-dev)	2.2665	-
This PR	2.2665	➡️ 0.0000 (0.00%)

✅ Difftest smoke test passed!