Implement lock striping for cmap

[hackerwins]

What this PR does / why we need it:

Implement lock striping for cmap

This change introduces lock striping to improve concurrent map performance by
reducing lock contention. Instead of using a single lock for the entire map,
the implementation divides the map into shards, each with its own lock,
allowing for better parallelism and throughput in concurrent operations.

Which issue(s) this PR fixes:

Fixes #

Special notes for your reviewer:

Does this PR introduce a user-facing change?:

Additional documentation:

Checklist:

• Added relevant tests or not required
• Didn't break anything

Summary by CodeRabbit

• New Features

  • Enhanced concurrency for the map structure, allowing for improved performance during simultaneous access.
  • Introduced sharding for more efficient data management.

• Bug Fixes

  • Reduced contention issues by updating locking mechanisms for operations on the map.

• Documentation

  • Updated function signatures for clarity and consistency.

[coderabbitai]

Walkthrough

The changes in this pull request significantly modify the Map structure in the cmap package, shifting from a single mutex-protected map to a concurrent map that employs sharding for better performance. A constant for the number of shards is introduced, along with a new shard type that encapsulates a mutex and a map. The Map type is updated to include an array of these shards, and various methods are adjusted to lock only the relevant shard instead of the entire map, enhancing concurrency.

Changes

File	Change Summary
pkg/cmap/cmap.go	Introduced const numShards = 32 and type shard[K comparable, V any] struct. Updated Map to include an array of shards. Modified New function to initialize shards. Added shardForKey and shardOf methods. Updated locking in Set, Upsert, Get, Delete, Has, Len, Keys, and Values methods. Renamed parameter in UpsertFunc from valueInMap to value.

Sequence Diagram(s)

sequenceDiagram
    participant Client
    participant Map
    participant Shard

    Client->>Map: Set(key, value)
    Map->>Shard: shardForKey(key)
    Shard->>Shard: Lock()
    Shard->>Shard: Store value
    Shard->>Map: Unlock()
    Map->>Client: Acknowledge

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[codecov]

Codecov Report

Attention: Patch coverage is 81.81818% with 14 lines in your changes missing coverage. Please review.

Project coverage is 46.76%. Comparing base (553e240) to head (9dcf72d).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
pkg/cmap/cmap.go	81.81%	13 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1053      +/-   ##
==========================================
+ Coverage   46.66%   46.76%   +0.09%     
==========================================
  Files          82       82              
  Lines       11959    12001      +42     
==========================================
+ Hits         5581     5612      +31     
- Misses       5816     5826      +10     
- Partials      562      563       +1     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[coderabbitai]

Actionable comments posted: 4

📜 Review details

Configuration used: CodeRabbit UI
Review profile: CHILL

📥 Commits

Files that changed from the base of the PR and between 553e240 and 9dcf72d.

📒 Files selected for processing (1)

• pkg/cmap/cmap.go (2 hunks)

🧰 Additional context used

🪛 golangci-lint

pkg/cmap/cmap.go

[high] 60-60: G115: integer overflow conversion int -> uint32

(gosec)