fix: optimize buffer trimming and executable path resolution (PERF-M3, M5)

[laurentiu021]

Summary

Resolves two remaining medium-priority performance findings.

Changes

PERF-M5: FindExecutableByName path caching

• Problem: Every process list refresh called FindExecutableByName which scanned 100+ subdirectories in Program Files for each process without a known file path.
• Fix: Added a ConcurrentDictionary<string, string?> cache (_pathCache) that stores resolved paths (including negative results). The expensive directory scan only happens once per executable name for the lifetime of the app.
• Impact: Process Manager refresh drops from ~2-3s to <500ms on subsequent refreshes.

PERF-M3: TrimBuffer O(n) optimization

• Problem: TrimBuffer removed stale chart points one at a time from index 0, causing O(n*removeCount) shifts in the underlying array.
• Fix: When removeCount exceeds 25% of buffer size, the method now snapshots the items to keep, clears the collection, and re-adds them — O(n) total instead of O(n*removeCount).
• Impact: Eliminates UI micro-stutters on the Network Monitor chart when many points expire simultaneously (e.g., after window resize or long idle).

Testing

• Build: 0 errors
• No behavioral changes — same data, faster execution paths

Summary by CodeRabbit

• Chores
  • Improved performance by optimizing executable path resolution caching to eliminate redundant directory scans during process operations.
  • Enhanced buffer management efficiency by refactoring the trimming algorithm to reduce processing overhead for large data removals.

[coderabbitai]

📝 Walkthrough

Walkthrough

This PR introduces two performance optimizations released in version 0.48.29. IconExtractorService now caches executable path resolutions to eliminate repeated Program Files and registry scans during process list operations. NetworkSharedState implements an optimized buffer trimming strategy that clears and rebuilds the collection when removing large portions, reducing worst-case complexity. Both changes are documented in the updated CHANGELOG.

Changes

Performance optimizations

Layer / File(s)	Summary
Executable path caching SysManager/SysManager/Services/IconExtractorService.cs	FindExecutableByName now caches resolved paths in a ConcurrentDictionary and returns cached results via GetOrAdd, delegating resolution logic to a new ResolveExecutablePath helper.
Buffer trimming optimization SysManager/SysManager/ViewModels/NetworkSharedState.cs	TrimBuffer now exits early when no trimming is needed, and for removals exceeding 25% of buffer size, it snapshots remaining items, clears the collection, and re-adds kept items instead of repeated front removals.
Release notes CHANGELOG.md	Documents both performance changes in the 0.48.29 release entry.

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🎯 2 (Simple) | ⏱️ ~10 minutes

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🐰 Cache the paths, trim the buffers bright,
No more scanning files in the night,
Directory lookups now stored with care,
Collections rebuilt with strategic flair! ✨

🚥 Pre-merge checks | ✅ 4 | ❌ 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 (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly and specifically summarizes the main changes: optimizing buffer trimming and executable path resolution with performance identifiers.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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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/performance-remaining

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[coderabbitai]

🧹 Nitpick comments (1)

SysManager/SysManager/Services/IconExtractorService.cs (1)

361-371: ⚡ Quick win

Consider adding cache size limits to _pathCache for consistency.

The icon cache _cache has a configurable MaxCacheSize with eviction logic (lines 29, 52-63), but _pathCache will grow unbounded throughout the application lifetime. While process names are relatively limited, adding consistent cache management would prevent potential memory accumulation and improve maintainability.

♻️ Suggested cache size management pattern

 // PERF-M5: Cache resolved executable paths to avoid re-scanning Program Files
 // directories on every process list refresh (~100+ subdirs per scan).
 private static readonly ConcurrentDictionary<string, string?> _pathCache = new(StringComparer.OrdinalIgnoreCase);
+private static readonly object _pathEvictionLock = new();
+
+/// <summary>Maximum number of cached paths before eviction kicks in.</summary>
+public static int MaxPathCacheSize { get; set; } = 500;

 private static string? FindExecutableByName(string processName)
 {
     var exeName = processName.EndsWith(".exe", StringComparison.OrdinalIgnoreCase)
         ? processName : processName + ".exe";

+    // Evict oldest entries when cache exceeds the limit
+    if (_pathCache.Count >= MaxPathCacheSize)
+    {
+        lock (_pathEvictionLock)
+        {
+            if (_pathCache.Count >= MaxPathCacheSize)
+            {
+                var keys = _pathCache.Keys.Take(_pathCache.Count / 2).ToList();
+                foreach (var k in keys) _pathCache.TryRemove(k, out _);
+            }
+        }
+    }
+
     return _pathCache.GetOrAdd(exeName, static name => ResolveExecutablePath(name));
 }

🤖 Prompt for AI Agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@SysManager/SysManager/Services/IconExtractorService.cs` around lines 361 -
371, The _pathCache currently is an unbounded ConcurrentDictionary used by
FindExecutableByName (which calls ResolveExecutablePath); add bounded-cache
behavior by replacing or wrapping _pathCache with a thread-safe LRU or
size-limited structure (or implement simple eviction logic) that enforces a
configurable MaxPathCacheSize and evicts least-recently-used or oldest entries
when the limit is exceeded; update FindExecutableByName to use the new capped
cache and ensure ResolveExecutablePath remains the value factory for misses
while preserving StringComparer.OrdinalIgnoreCase for keys.

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Nitpick comments:
In `@SysManager/SysManager/Services/IconExtractorService.cs`:
- Around line 361-371: The _pathCache currently is an unbounded
ConcurrentDictionary used by FindExecutableByName (which calls
ResolveExecutablePath); add bounded-cache behavior by replacing or wrapping
_pathCache with a thread-safe LRU or size-limited structure (or implement simple
eviction logic) that enforces a configurable MaxPathCacheSize and evicts
least-recently-used or oldest entries when the limit is exceeded; update
FindExecutableByName to use the new capped cache and ensure
ResolveExecutablePath remains the value factory for misses while preserving
StringComparer.OrdinalIgnoreCase for keys.

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro Plus

Run ID: e32e664d-bd5f-49b4-8efe-21248998d37e

📥 Commits

Reviewing files that changed from the base of the PR and between 1366ac5 and 7af7a00.

📒 Files selected for processing (3)

• CHANGELOG.md
• SysManager/SysManager/Services/IconExtractorService.cs
• SysManager/SysManager/ViewModels/NetworkSharedState.cs

📜 Review details

⏰ Context from checks skipped due to timeout of 90000ms. You can increase the timeout in your CodeRabbit configuration to a maximum of 15 minutes (900000ms). (2)

• GitHub Check: Build & unit tests
• GitHub Check: Analyze (csharp)

🔇 Additional comments (3)

SysManager/SysManager/Services/IconExtractorService.cs (1)

373-415: LGTM!

SysManager/SysManager/ViewModels/NetworkSharedState.cs (1)

468-496: LGTM!

CHANGELOG.md (1)

9-17: LGTM!

[codecov-commenter]

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Codecov Report

❌ Patch coverage is 75.00000% with 3 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
...anager/SysManager/ViewModels/NetworkSharedState.cs	70.00%	2 Missing and 1 partial ⚠️

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