dashboard: add keyboard shortcuts and optimize polling

- fetch.py: convert proxy validation cache to LRU with OrderedDict
  - thread-safe lock, move_to_end() on hits, evict oldest when full
- dashboard.js: add keyboard shortcuts (r=refresh, 1-9=tabs, t=theme, p=pause)
- dashboard.js: skip chart rendering for inactive tabs (reduces CPU)

fetch.py

@@ -1,6 +1,7 @@
 import re, random, time, string
 import json
 import threading
+from collections import OrderedDict
 import rocksock
 import network_stats
 from http2 import RsHttp, _parse_url
@@ -9,9 +10,11 @@ from misc import _log, tor_proxy_url
 
 config = None
 
-# Cache for is_usable_proxy() - avoids repeated validation of same proxy strings
-_proxy_valid_cache = {}
+# LRU cache for is_usable_proxy() - avoids repeated validation of same proxy strings
+# Uses OrderedDict to maintain insertion order; oldest entries evicted when full
+_proxy_valid_cache = OrderedDict()
 _proxy_valid_cache_max = 10000
+_proxy_valid_cache_lock = threading.Lock()
 
 
 class FetchSession(object):
@@ -603,16 +606,20 @@ def is_usable_proxy(proxy):
     - Invalid port (0, >65535)
     - Private/reserved ranges
 
-    Results are cached to avoid repeated validation of the same proxy strings.
+    Results are cached using LRU eviction to avoid repeated validation.
     """
-    # Check cache first
+    with _proxy_valid_cache_lock:
         if proxy in _proxy_valid_cache:
+            # Move to end (most recently used)
+            _proxy_valid_cache.move_to_end(proxy)
             return _proxy_valid_cache[proxy]
 
     result = _validate_proxy(proxy)
 
-    # Cache result (with size limit)
-    if len(_proxy_valid_cache) < _proxy_valid_cache_max:
+    with _proxy_valid_cache_lock:
+        # Evict oldest entries if at capacity
+        while len(_proxy_valid_cache) >= _proxy_valid_cache_max:
+            _proxy_valid_cache.popitem(last=False)
         _proxy_valid_cache[proxy] = result
 
     return result

static/dashboard.js

@@ -9,6 +9,17 @@ var uplotCharts = {};
 // Chart.js instances (persistent)
 var chartJsInstances = {};
 
+// Get currently active tab ID
+function getActiveTab() {
+    var activeBtn = document.querySelector('.tab-btn.active');
+    return activeBtn ? activeBtn.dataset.tab : 'overview';
+}
+
+// Check if a specific tab is currently active
+function isTabActive(tabId) {
+    return getActiveTab() === tabId;
+}
+
 // Tab switching
 function initTabs() {
     $$('.tab-btn').forEach(function(btn) {
@@ -331,10 +342,15 @@ function update(d) {
     // System
     $('uptime').textContent = fmtTime(d.uptime_seconds);
 
-    // Charts
+    // Charts - only render for active tabs to reduce CPU usage
+    var activeTab = getActiveTab();
+    if (activeTab === 'overview' || activeTab === 'perf') {
         renderLineChart('rateChart', d.rate_history, '#58a6ff', d.peak_rate * 1.1);
         renderLineChart('srChart', d.success_rate_history, '#3fb950', 100);
+    }
+    if (activeTab === 'perf') {
         renderHistogram('latencyHisto', d.latency_histogram);
+    }
 
     // Protocol breakdown
     var ps = d.proto_stats || {};
@@ -347,9 +363,9 @@ function update(d) {
         rateEl.className = 'proto-rate ' + (s.success_rate < 20 ? 'tag-err' : s.success_rate < 50 ? 'tag-warn' : 'tag-ok');
     });
 
-    // Results pie (Chart.js doughnut)
+    // Results pie (Chart.js doughnut) - only on overview tab
     var passed = d.passed || 0, failed = d.failed || 0, total = passed + failed;
-    if (total > 0) {
+    if (activeTab === 'overview' && total > 0) {
         renderDoughnutChart('resultsPie', ['Passed', 'Failed'], [passed, failed], ['#3fb950', '#f85149']);
     }
     $('passedLeg').textContent = fmt(passed);
@@ -357,13 +373,15 @@ function update(d) {
     $('failedLeg').textContent = fmt(failed);
     $('failedPct').textContent = pct(failed, total) + '%';
 
-    // Failures breakdown (Chart.js doughnut)
+    // Failures breakdown (Chart.js doughnut) - only on overview tab
     var fhtml = '', failColors = ['#f85149','#db6d28','#d29922','#58a6ff','#a371f7','#39c5cf','#db61a2','#7d8590'];
     if (d.failures && Object.keys(d.failures).length > 0) {
         var cats = Object.keys(d.failures).sort(function(a,b) { return d.failures[b] - d.failures[a]; });
+        if (activeTab === 'overview') {
             var failVals = cats.map(function(c) { return d.failures[c]; });
             var failCols = cats.map(function(_, i) { return failColors[i % failColors.length]; });
             renderDoughnutChart('failPie', cats, failVals, failCols);
+        }
         cats.forEach(function(cat, i) {
             var n = d.failures[cat], col = failColors[i % failColors.length];
             fhtml += '<div class="legend-item"><div class="legend-dot" style="background:' + col + '"></div>';
@@ -377,7 +395,7 @@ function update(d) {
     // Leaderboards (session data)
     renderLeaderboard('topAsns', d.top_asns_session, 'asn', 'count');
 
-    // Country pie chart (Chart.js doughnut)
+    // Country pie chart (Chart.js doughnut) - only on overview/db tabs
     var countryColors = ['#58a6ff','#3fb950','#d29922','#f85149','#a371f7','#39c5cf','#db61a2','#db6d28','#7ee787','#7d8590'];
     if (d.db && d.db.top_countries && d.db.top_countries.length > 0) {
         var countries = d.db.top_countries.slice(0, 8);
@@ -394,7 +412,9 @@ function update(d) {
             chtml += '<span class="legend-name">' + code + '</span><span class="legend-val">' + fmt(cnt) + '</span>';
             chtml += '<span class="sub" style="margin-left:4px">' + pctVal + '%</span></div>';
         });
+        if (activeTab === 'overview' || activeTab === 'db') {
             renderDoughnutChart('countryPie', cLabels, cValues, cColors);
+        }
         $('countryLegend').innerHTML = chtml;
     } else {
         $('countryLegend').innerHTML = '<div style="color:var(--dim);font-size:11px">No data</div>';
@@ -707,6 +727,47 @@ function handleVisibilityChange() {
 
 document.addEventListener('visibilitychange', handleVisibilityChange);
 
+// Keyboard shortcuts
+document.addEventListener('keydown', function(e) {
+    // Ignore if typing in input/textarea
+    if (e.target.tagName === 'INPUT' || e.target.tagName === 'TEXTAREA') return;
+
+    var key = e.key.toLowerCase();
+
+    // r = refresh
+    if (key === 'r' && !e.ctrlKey && !e.metaKey) {
+        fetchStats();
+        return;
+    }
+
+    // 1-9 = switch tabs
+    if (key >= '1' && key <= '9') {
+        var tabs = document.querySelectorAll('.tab-btn');
+        var idx = parseInt(key) - 1;
+        if (tabs[idx]) {
+            tabs[idx].click();
+        }
+        return;
+    }
+
+    // t = cycle theme
+    if (key === 't' && !e.ctrlKey && !e.metaKey) {
+        var btn = document.getElementById('themeToggle');
+        if (btn) btn.click();
+        return;
+    }
+
+    // p = toggle polling pause
+    if (key === 'p' && !e.ctrlKey && !e.metaKey) {
+        if (pollInterval) {
+            stopPolling();
+        } else {
+            startPolling();
+        }
+        return;
+    }
+});
+
 // Initial start
 if (!document.hidden) {
     startPolling();