Actium

@TheHoff I have reason to believe that a KVM-hosted Windows VM running the DCS dedicated server does perform substantially worse (by orders of magnitude) than Windows running unvirtualized on the same hardware. Details including benchmarks. Running DCS_server.exe directly on the host via Wine appears to perform much better than using an intermediary Windows VM.

I've run a bunch of benchmarks that point to the dedicated server performing very poorly under KVM, which I presume winboat relies upon. Since the client and dedicated server presumably share the same code base, I'd be weary that trying to run the DCS client in a VM may affect the performance significantly. If you give it a try, make sure to benchmark it against native performance and do share you results.

@BIGNEWY Any updates on this? The arbitrary code execution vulnerability is still exploitable in both client (CVSS 8.6) and dedicated server (CVSS 8.8) as of right now. It's been exactly 10 months since I've first reported the issue confidentially along with a proof-of-concept exploit (see support ticket #176799). I understand that a proper fix that doesn't break the scripting API is a non-trivial task that will take some time. Until then, a temporary stopgap exploit mitigation should be deployed. It is reckless to leave DCS trivially exploitable. I've suggested a straightforward mitigation more than 3 months ago (ticket #190402) and also posted it in this thread, which I've updated just now to add logging. Please address security vulnerabilities with the urgency they deserve! Feel free to reach out if you need help with that. P.S.: %DCS_INSTALL_DIR%/API/Sim_ControlAPI.html still contains the revoked security option configuration directives. Please update the documentation accordingly.

Thread wasn't moved, so I posted a new bug report in the Game Crash section: @Maverick Su-35S If you happen to have a crashdump, please post it there.

The DCS client and server quit with a "Login session has expired" popup when reconnecting to the master server after the connection had been lost for about half an hour. Said quitting now appears to trigger a delayed segmentation fault. Originally reported here. Full crash dump: dcs.log-20251003-120952.zip Annotated excerpt from dcs.log: # tabbing in and out, everything works prior to computer suspension 2025-10-03 11:15:20.855 INFO DXGUI_WIN_ADAPTER (Main): resize main window to [2560, 1440] 2025-10-03 11:15:22.549 INFO DXGUI_WIN_ADAPTER (Main): resize main window to [0, 0] 2025-10-03 11:16:57.822 INFO DXGUI_WIN_ADAPTER (Main): resize main window to [2560, 1440] 2025-10-03 11:17:02.051 INFO DXGUI_WIN_ADAPTER (Main): resize main window to [0, 0] 2025-10-03 11:21:16.576 INFO DXGUI_WIN_ADAPTER (Main): resize main window to [2560, 1440] 2025-10-03 11:21:17.875 INFO DXGUI_WIN_ADAPTER (Main): resize main window to [0, 0] ... # coming back up from suspension, the session check fails immediately 2025-10-03 12:06:56.534 ERROR ASYNCNET (2808): HTTP request dcs:checksession failed with error 6: Could not resolve hostname 2025-10-03 12:06:56.535 WARNING ASYNCNET (2808): Session check failed: -6 ... # a minute later, DCS decides to terminate, but lets me tab in and out anyway 2025-10-03 12:07:57.966 ERROR ASYNCNET (2808): The session has expired (401). Exiting... 2025-10-03 12:07:57.972 INFO EDCORE (Main): (dDispatcher)enterToState_:5 2025-10-03 12:08:38.747 INFO DXGUI_WIN_ADAPTER (Main): resize main window to [2560, 1440] 2025-10-03 12:08:42.582 INFO DXGUI_WIN_ADAPTER (Main): resize main window to [0, 0] 2025-10-03 12:09:42.972 INFO DXGUI_WIN_ADAPTER (Main): resize main window to [2560, 1440] 2025-10-03 12:09:48.735 INFO APP (Main): application shutdown ... # two minutes later, DCS suddenly SEGFAULTs 2025-10-03 12:09:49.196 WARNING SCENE (8972): Scene was removed with 1 alive objects 2025-10-03 12:09:49.210 INFO WorldPlugIns (Main): Deinitializing plugins... 2025-10-03 12:09:50.441 INFO TERRAIN (Main): lSystem::exit() 2025-10-03 12:09:50.443 INFO TERRAIN (Main): lSystem::CleanScenes() 2025-10-03 12:09:50.443 INFO WORLDGENERAL (Main): TerrainUtility:: updated in parallel: 0, updated in the main thread: 0 2025-10-03 12:09:50.504 INFO INTER (8972): ITerrainGraphicsEntryPoint::close() 2025-10-03 12:09:50.564 INFO INTER (Main): ITerrainEntryPoint::close() 2025-10-03 12:09:51.160 INFO INTER (Main): ITerrainGraphicsEntryPoint::close() 2025-10-03 12:09:51.160 INFO INTER (Main): ITerrainEntryPoint::close() 2025-10-03 12:09:51.161 INFO EDCORE (Main): try to write dump information 2025-10-03 12:09:51.163 WARNING SCENE (8972): Scene was removed with 5 alive objects 2025-10-03 12:09:51.271 INFO EDCORE (Main): # -------------- 20251003-120952 -------------- 2025-10-03 12:09:51.273 INFO EDCORE (Main): DCS/2.9.20.15384 (x86_64; MT; Windows NT 10.0.19045) 2025-10-03 12:09:51.275 INFO EDCORE (Main): C:\Games\DCS World OpenBeta\bin\lua.dll 2025-10-03 12:09:51.277 INFO EDCORE (Main): # C0000005 ACCESS_VIOLATION at 00007ff9994817d0 00:00000000 2025-10-03 12:09:51.279 INFO EDCORE (Main): SymInit: Symbol-SearchPath: 'C:\Games\DCS World OpenBeta\bin;', symOptions: 532, UserName: 'user' 2025-10-03 12:09:51.281 INFO EDCORE (Main): OS-Version: 10.0.19045 () 0x100-0x1 2025-10-03 12:09:51.282 INFO EDCORE (Main): 0x00000000000017d0 (lua): lua_gettop + 0x0 2025-10-03 12:09:51.284 INFO EDCORE (Main): 0x00000000000761eb (edCore): Lua::Config::Config + 0x1B 2025-10-03 12:09:51.286 INFO EDCORE (Main): 0x0000000000a980de (DCS): SW + 0x47BEAE 2025-10-03 12:09:51.286 INFO DX11BACKEND (8972): DX11Renderer::shutdown() 2025-10-03 12:09:51.288 INFO EDCORE (Main): 0x0000000000a97c32 (DCS): SW + 0x47BA02 2025-10-03 12:09:51.290 INFO EDCORE (Main): 0x0000000000a9078b (DCS): SW + 0x47455B 2025-10-03 12:09:51.290 INFO EDCORE (Main): 0x0000000000a45aaf (DCS): SW + 0x42987F 2025-10-03 12:09:51.291 INFO EDCORE (Main): 0x000000000015a56a (Visualizer): smSceneManager::DestroySceneManager + 0xCA 2025-10-03 12:09:51.291 INFO EDCORE (Main): 0x0000000000a66f36 (DCS): SW + 0x44AD06 2025-10-03 12:09:51.291 INFO EDCORE (Main): 0x00000000025b8da1 (DCS): AmdPowerXpressRequestHighPerformance + 0x1097D9D 2025-10-03 12:09:51.291 INFO EDCORE (Main): 0x00000000010dac82 (DCS): SW + 0xABEA52 2025-10-03 12:09:51.291 INFO EDCORE (Main): 0x0000000000017374 (KERNEL32): BaseThreadInitThunk + 0x14 2025-10-03 12:09:51.504 INFO EDCORE (Main): Minidump created.

The dedicated server actually runs hassle-free on vanilla Wine. Unfortunately, the performance is worse than Windows on bare metal. Coincidentally, Wine 10.16 with upstreamed NTSYNC support came out last week. I'm expecting/hoping/praying for that to make a significant performance impact, but I haven't had the time to run new benchmarks.

Lolz. Exact same situation here. No need to apologize. Glad we could clear that up.

My genuine apologies for my curt inquiry if it came across as impolite! I've read the entire thread and was merely curious as to where that information originated from, as I've never read anything about it and – as you rightfully mentioned – ED could improve in terms of documentation and answering technical questions on this forum. I appreciate your efforts to step in!

S_EVENT_SHOT triggers when firing a weapon, not when it impacts. Dunno whether S_EVENT_HIT will trigger when a bomb hits the ground without damaging any units. Also unsure whether your use of addEventHandler() is correct. See here for an exemplary use of S_EVENT_HIT to detect (H)ARMs that hit a ship:

The dedicated server has been multi-threaded for at least a year. However, the main thread is the apparent bottleneck, which uses up considerably more CPU cycles than all other threads combined. On a multi-core CPU, that will result in a low overall CPU usage. See this Process Explorer screenshot (right-click DCS_server.exe -> Properties): Where are you getting that from? AFAICT from logs, bugs/inconsistencies, and its UI, the dedicated server shares a large swath of its codebase with the client. As the latter can host multiplayer missions, re-using that code makes sense. Thus, all hosting-related improvements to the client should end up in the dedicated server immediately. On a side note, the dedicated server even exaggerates code sharing a bit by incorporating the client's interactive error handling, which is unsuitable for a background service like a dedicated server.

@MsKatze If you want a trimmed down version of Windows 11 for hosting DCS, you can try Tiny11. The official price for Windows Server 2025 is truly ludicrous ($1,176 for a ridiculous 16 cores).

Recently noticed that when running DCS_server.exe on Linux via Wine, three threads set civetweb-worker as their custom thread name. Presumably, these threads run the CivetWeb Embedded C/C++ web server to provide the server-side JSON interface of the DCS WebGUI. However, CivetWeb is not credited in Doc/3RD-PARTIES.txt. That would be an infringement of Civetweb License, which requires inclusion of the copyright notice and license text just like the MIT license from which it appears to be derived. I assume this is simply a benign oversight that is easy to rectify. Unfortunately, there's no easy way to show custom thread names under Windows, so above Linux htop screenshot will have to do. The Wine codebase does not rely on civetweb (grep -rin 'civet' turns up nothing), so the origin of the thread names must be the DCS server executable itself. I see no reason why these threads would be named civetweb-worker other than running the civetweb code.

@BIGNEWY Reproduced. This is an actual crash (SEGFAULT / ACCESS_VIOLATION). Please move to Game Crash. Being naive and having suspended my computer while I had the DCS Mission Editor open, I accidentally triggered this crash. Full dump attached: dcs.log-20251003-120952.zip Annotated excerpt from dcs.log: # tabbing in and out, everything works prior to computer suspension 2025-10-03 11:15:20.855 INFO DXGUI_WIN_ADAPTER (Main): resize main window to [2560, 1440] 2025-10-03 11:15:22.549 INFO DXGUI_WIN_ADAPTER (Main): resize main window to [0, 0] 2025-10-03 11:16:57.822 INFO DXGUI_WIN_ADAPTER (Main): resize main window to [2560, 1440] 2025-10-03 11:17:02.051 INFO DXGUI_WIN_ADAPTER (Main): resize main window to [0, 0] 2025-10-03 11:21:16.576 INFO DXGUI_WIN_ADAPTER (Main): resize main window to [2560, 1440] 2025-10-03 11:21:17.875 INFO DXGUI_WIN_ADAPTER (Main): resize main window to [0, 0] ... # coming back up from suspension, the session check fails immediately 2025-10-03 12:06:56.534 ERROR ASYNCNET (2808): HTTP request dcs:checksession failed with error 6: Could not resolve hostname 2025-10-03 12:06:56.535 WARNING ASYNCNET (2808): Session check failed: -6 ... # a minute later, DCS decides to terminate, but lets me tab in and out anyway 2025-10-03 12:07:57.966 ERROR ASYNCNET (2808): The session has expired (401). Exiting... 2025-10-03 12:07:57.972 INFO EDCORE (Main): (dDispatcher)enterToState_:5 2025-10-03 12:08:38.747 INFO DXGUI_WIN_ADAPTER (Main): resize main window to [2560, 1440] 2025-10-03 12:08:42.582 INFO DXGUI_WIN_ADAPTER (Main): resize main window to [0, 0] 2025-10-03 12:09:42.972 INFO DXGUI_WIN_ADAPTER (Main): resize main window to [2560, 1440] 2025-10-03 12:09:48.735 INFO APP (Main): application shutdown ... # two minutes later, DCS suddenly SEGFAULTs 2025-10-03 12:09:49.196 WARNING SCENE (8972): Scene was removed with 1 alive objects 2025-10-03 12:09:49.210 INFO WorldPlugIns (Main): Deinitializing plugins... 2025-10-03 12:09:50.441 INFO TERRAIN (Main): lSystem::exit() 2025-10-03 12:09:50.443 INFO TERRAIN (Main): lSystem::CleanScenes() 2025-10-03 12:09:50.443 INFO WORLDGENERAL (Main): TerrainUtility:: updated in parallel: 0, updated in the main thread: 0 2025-10-03 12:09:50.504 INFO INTER (8972): ITerrainGraphicsEntryPoint::close() 2025-10-03 12:09:50.564 INFO INTER (Main): ITerrainEntryPoint::close() 2025-10-03 12:09:51.160 INFO INTER (Main): ITerrainGraphicsEntryPoint::close() 2025-10-03 12:09:51.160 INFO INTER (Main): ITerrainEntryPoint::close() 2025-10-03 12:09:51.161 INFO EDCORE (Main): try to write dump information 2025-10-03 12:09:51.163 WARNING SCENE (8972): Scene was removed with 5 alive objects 2025-10-03 12:09:51.271 INFO EDCORE (Main): # -------------- 20251003-120952 -------------- 2025-10-03 12:09:51.273 INFO EDCORE (Main): DCS/2.9.20.15384 (x86_64; MT; Windows NT 10.0.19045) 2025-10-03 12:09:51.275 INFO EDCORE (Main): C:\Games\DCS World OpenBeta\bin\lua.dll 2025-10-03 12:09:51.277 INFO EDCORE (Main): # C0000005 ACCESS_VIOLATION at 00007ff9994817d0 00:00000000 2025-10-03 12:09:51.279 INFO EDCORE (Main): SymInit: Symbol-SearchPath: 'C:\Games\DCS World OpenBeta\bin;', symOptions: 532, UserName: 'user' 2025-10-03 12:09:51.281 INFO EDCORE (Main): OS-Version: 10.0.19045 () 0x100-0x1 2025-10-03 12:09:51.282 INFO EDCORE (Main): 0x00000000000017d0 (lua): lua_gettop + 0x0 2025-10-03 12:09:51.284 INFO EDCORE (Main): 0x00000000000761eb (edCore): Lua::Config::Config + 0x1B 2025-10-03 12:09:51.286 INFO EDCORE (Main): 0x0000000000a980de (DCS): SW + 0x47BEAE 2025-10-03 12:09:51.286 INFO DX11BACKEND (8972): DX11Renderer::shutdown() 2025-10-03 12:09:51.288 INFO EDCORE (Main): 0x0000000000a97c32 (DCS): SW + 0x47BA02 2025-10-03 12:09:51.290 INFO EDCORE (Main): 0x0000000000a9078b (DCS): SW + 0x47455B 2025-10-03 12:09:51.290 INFO EDCORE (Main): 0x0000000000a45aaf (DCS): SW + 0x42987F 2025-10-03 12:09:51.291 INFO EDCORE (Main): 0x000000000015a56a (Visualizer): smSceneManager::DestroySceneManager + 0xCA 2025-10-03 12:09:51.291 INFO EDCORE (Main): 0x0000000000a66f36 (DCS): SW + 0x44AD06 2025-10-03 12:09:51.291 INFO EDCORE (Main): 0x00000000025b8da1 (DCS): AmdPowerXpressRequestHighPerformance + 0x1097D9D 2025-10-03 12:09:51.291 INFO EDCORE (Main): 0x00000000010dac82 (DCS): SW + 0xABEA52 2025-10-03 12:09:51.291 INFO EDCORE (Main): 0x0000000000017374 (KERNEL32): BaseThreadInitThunk + 0x14 2025-10-03 12:09:51.504 INFO EDCORE (Main): Minidump created.

Did a quick test (on Windows 10). Newly created, empty mission on Caucasus. Added a ONCE trigger with the SOUND TO ALL action and could open the file chooser dialog:

Does it actually crash or does it quit with a Login session has expired popup message? I've reported the latter more than half a year ago: