Optimize load_session_torrents code path #1546
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jesec
commented
Jul 19, 2025
jesec
commented
| Torrents / Time to Load (seconds) | w/o this PR | w/ this PR |
|---|---|---|
| 100 | 0.0988322 | 0.100783 |
| 500 | 0.316298 | 0.2778484 |
| 1000 | 0.5230036 | 0.3384636 |
| 2000 | 1.1452586 | 0.488410 |
| 5000 | 5.4459174 | 0.8843604 |
| 10000 | 24.0999498 | 1.574791 |
| 15000 | 62.0685972 | 2.3090436 |
| 20000 | 122.2196932 | 3.118153 |
| 25000 | 194.3020272 | 3.9291368 |
| 30000 | 301.594044 | 4.7896626 |
Eliminate O(n²) hash checking overhead during session loading by moving hashing view initialization to after session torrents are loaded. Performance Impact: - Before: O(n²) - each session torrent triggers individual hash processing - After: O(n) - all session torrents processed in single batch when view connects - Critical speedup when loading thousands of session torrents at startup Implementation leverages existing view signal system: - Session torrents load without triggering hash checking - Hashing view connects after loading and naturally batch-processes all torrents - No additional state management or complexity needed This approach is more elegant than batch mode flags as it uses the view system's natural batching behavior when initially populated.
…ading Bypass scheduler queuing for session torrents to eliminate priority queue operations during bulk session loading. Performance Impact: - Before: O(n*log n) due to scheduler priority queue operations - After: O(n) direct execution for session torrents - Critical speedup when loading thousands of session torrents at startup Leverages existing m_session flag to automatically detect session torrents and use direct execution path while preserving async handling for regular torrents.
Eliminate expensive view sorting when running in daemon mode where RPC clients handle their own sorting. Performance Impact: - Before: O(n*log n) sorting operations per view update - After: O(1) - sorting completely disabled when not needed - Critical benefit for RPC clients like Flood/ruTorrent Sorting is only enabled in interactive mode where users need visually sorted download lists.
Add fast path for view insertion that skips expensive sorted insertion when no sorting criteria are configured. Performance Impact: - Before: O(n) std::find_if search for insertion position always - After: O(1) direct insertion at end when sorting not required - Significant speedup for unsorted views during bulk operations Particularly benefits session loading and views without sort commands.
Add fast path for View::filter_download() that avoids expensive search for newly added downloads. Performance Impact: - Before: O(n) std::find() search through entire view always - After: O(1) check for newly added downloads at end position first - Reduces session loading from O(n²) to O(n) for filter operations Newly added downloads are always at vector end, making this optimization highly effective during bulk session loading.
…n torrents Skip expensive download list verification check during session loading since session torrents are trusted and cannot be removed immediately. Performance Impact: - Before: O(n) download list search per session torrent - After: O(1) - verification skipped for session torrents only - Reduces session loading verification from O(n²) to O(n) Session torrents are pre-validated and trusted, making this verification redundant and expensive.
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impressive. |
rakshasa
reviewed
Aug 2, 2025
| rpc::call_command("d.state.set", (int64_t)m_start, rpc::make_target(download)); | ||
| if (!m_session) { | ||
| if (m_manager->download_list()->find(infohash) == m_manager->download_list()->end()) | ||
| throw torrent::input_error("The newly created download was removed."); |
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How big of an effect does this change have?
As session torrents are loaded after Control is initialized, we can still delete torrents during session load using xmlrpc. (or other event triggers)
rakshasa
reviewed
Aug 2, 2025
| "schedule2 = view.main,10,10,((view.sort,main,20))\n" | ||
| "schedule2 = view.name,10,10,((view.sort,name,20))\n" | ||
| ); | ||
| } |
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Daemon mode still uses views, so the name view should be sorted.
However this could be changed to be added on event.system.startup_done, which likely should also be used to enable scgi if opened.
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