Performance issues in Academy Overview (GRT audit findings)

[teodoroleckie]

🐛 Performance issues in Academy Overview (GRT audit findings)

Summary

After auditing the GRT codebase, several performance bottlenecks were identified, especially affecting the Academy Overview (_GRCRT_AO.d() and related functions).

With a moderate-to-large dataset (e.g. 100+ towns), these issues cause:

• Excessive CPU usage
• Noticeable UI lag
• Poor scalability due to O(n²) patterns
• Risk of browser freezing in extreme cases

Most problems stem from nested loops, redundant computations, and lack of caching.

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🔍 Observed Impact

• Severe slowdown when opening Academy Overview
• CPU spikes due to nested iterations
• Inefficient DOM access patterns
• Performance degradation grows exponentially with data size

---

📌 Identified Problems & Suggested Fixes

❗ Problem 1 — Nested loop O(n²) in _GRCRT_AO.d() (CRITICAL)

Issue:
For each town in N, the code iterates the entire P collection to find a match by ID.

This results in:

• O(n²) complexity (e.g. 100 towns → 10,000 iterations)

Current code:

$.each(N, function(ia, da) {
    P.forEach(function(U) {
        if (da.id == U.id) { ... }
    });
});

Suggested fix (use hash map for O(1) lookup):

var townMap = {};
P.forEach(function(U) { townMap[U.id] = U; });

$.each(N, function(ia, da) {
    var U = townMap[da.id];
    if (U) { ... }
});

❗ Problem 2 — A() called inside nested loop (CRITICAL)

Issue:
A() recalculates shared state (Y) and is called:

Inside the nested loop (multiple times)
Again inside k() (indirect duplication)

Current code:

$.each(N, function(ia, da) {
    P.forEach(function(U) {
        if (da.id == U.id) {
            A();
            var ua = k(U.id);
        }
    });
});

Suggested fix (compute once):

A();

$.each(N, function(ia, da) {
    var U = townMap[da.id];
    if (U) {
        var ua = k(U.id); // ensure k() does NOT call A()
    }
});

⚠️ Problem 3 — Manual bubble sort O(n²) (HIGH)

Issue:
A custom bubble sort is used instead of native sorting.

Current code:

var X = false;
do {
    X = false;
    for (var aa = 0; aa < N.length - 1; aa++) {
        if (N[aa].name > N[aa + 1].name) {
            X = N[aa]; N[aa] = N[aa + 1]; N[aa + 1] = X; X = true;
        }
    }
} while (X);

Suggested fix:

N.sort(function(a, b) {
    return a.name.localeCompare(b.name);
});

⚠️ Problem 4 — Repeated Object.size() in inner loop (HIGH)

Issue:
Object.size() iterates over the object and is called multiple times per iteration.

Current code:

var ba = Y && Y[U.id] && Object.size(Y[U.id]) == queueLen || false;

$.each(GameData.researches, function(Fa, $a) {
    var db = Y && Y[U.id] && Object.size(Y[U.id]) == queueLen || false;
});

Suggested fix (cache result):

var queueLen = GameDataConstructionQueue.getResearchOrdersQueueLength();
var ySize    = Y && Y[U.id] ? Object.size(Y[U.id]) : 0;
var ba       = ySize == queueLen;

$.each(GameData.researches, function(Fa, $a) {
    var db = ba;
});

⚠️ Problem 5 — Repeated jQuery selector in R() (HIGH)

Issue:
The same DOM query is executed for every iteration.

Current code:

$.each(Ha[Ua.toString()], function(u, H) {
    $("#grcrt_radar_result ul").append(...);
});

Suggested fix (cache selector):

var $ul = $("#grcrt_radar_result ul").html("");

$.each(Ha[Ua.toString()], function(u, H) {
    $ul.append(...);
});

⚠️ Problem 6 — ajaxComplete processes all windows on every request (MEDIUM)

Issue:
Runs on every AJAX call and iterates all open windows regardless of relevance.

Current code:

$(document).ajaxComplete(function(d, k, m) {
    $.each(Layout.wnd.getAllOpen(), function(p, C) {
        ...
    });
});

Suggested fix (early filtering):

$(document).ajaxComplete(function(d, k, m) {
    if (!RepConv.settings[RepConv.Cookie + "_trade"]) return;

    var url = m.url;
    if (url.indexOf("farm_town") === -1 && url.indexOf("island_info") === -1) return;

    $.each(Layout.wnd.getAllOpen(), function(p, C) { ... });
});

⚠️ Problem 7 — Linear search in getPlayerId4Name (MEDIUM)

Issue:
Performs O(n) lookup over all players.

Current code:

this.getPlayerId4Name = function(d) {
    var k;
    $.each(RepConv.cachePlayers, function(m, p) {
        p.name == d && (k = p.id);
    });
    return k || null;
};

Suggested fix (indexed lookup):

// Build index once
RepConv.cachePlayersByName = {};
$.each(k, function(m, p) {
    RepConv.cachePlayersByName[p.name] = p.id;
});

// O(1) lookup
this.getPlayerId4Name = function(d) {
    return RepConv.cachePlayersByName[d] || null;
};

🟡 Problem 8 — GetLabel() without memoization (LOW)

Issue:
Repeated string splitting and traversal on every call.

Current code:

this.GetLabel = function(d) {
    var k, m = d.split("."), p = RepConv.Lang;
    $.each(m, function(C, G) { ... });
    return k || this.getLabelLangArray(d);
};

Suggested fix (memoization):

var _labelCache = {};

this.GetLabel = function(d) {
    if (_labelCache[d] !== undefined) return _labelCache[d];

    var k, m = d.split("."), p = RepConv.Lang;
    $.each(m, function(C, G) { ... });

    return (_labelCache[d] = k || this.getLabelLangArray(d));
};

The most impactful issues (1 & 2) introduce quadratic complexity in critical rendering paths, especially when opening the Academy Overview.

Combined with redundant computations and DOM inefficiencies, these problems significantly affect performance and scalability.

🚀 Expected Outcome After Fixes
Reduced time complexity from O(n²) to O(n) in key paths
Lower CPU usage during rendering
Faster UI response times
Improved scalability for large accounts
Elimination of major browser slowdowns/freezes

[tomaski]

Wow, thank you for taking the time to make this comprehensive analysis.
We'll take a look and analyse your findings the soonest we can. However, as we're not actively playing anymore, it can take some time.