Eliminate conhost.exe from git.exe and hooks process launches#1981
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wilbaker
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GVFS launches git.exe processes with CreateNoWindow=true (or CREATE_NO_WINDOW in native code). Despite the name, this flag tells Windows to create a new hidden console for each child process, which allocates a conhost.exe instance. For frequent, small git operations (e.g., during prefetch), the per-process conhost creation/teardown overhead is disproportionately large. Changes: - GitProcess.cs: Set CreateNoWindow=false. With UseShellExecute=false and stdout/stderr redirected to pipes, the child inherits the parent's console state. Since GVFS.Mount runs as a service with no console, the child gets no console and no conhost. Also remove the unused redirectStandardError parameter (all callers pass true). - ProcessHelper.cs: Set CreateNoWindow=false unconditionally. When redirectOutput is true, I/O goes through pipes so no console is needed. When redirectOutput is false, the child inherits the parent's console handles, which is correct for terminal contexts and harmless in service contexts (output was already going to an invisible hidden console). - GitHooksLoader.cpp: Use DETACHED_PROCESS instead of CREATE_NO_WINDOW in the no-console branch. Explicitly detaches from any console without allocating a new one. The console branch (user terminal) is unchanged. Verified with edge-case tests across terminal, hidden-console, and fully-detached (DETACHED_PROCESS) parent contexts. All git status, git fetch (prefetch hook), and gvfs health scenarios pass. Assisted-by: Tyrie Vella <tyrielv@gmail.com> Assisted-by: Claude Opus 4.6 Signed-off-by: Tyrie Vella <tyrielv@gmail.com>
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tyrielv
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Summary
GVFS launches git.exe processes with
CreateNoWindow=true(orCREATE_NO_WINDOWin native code). Despite the name, this flag tells Windows to create a new hidden console for each child process, which allocates aconhost.exeinstance. For frequent, small git operations (e.g., during prefetch), the per-process conhost creation/teardown overhead is disproportionately large.Changes
GitProcess.cs:827CreateNoWindow = truetofalseProcessHelper.cs:21CreateNoWindow = redirectOutputtofalseGitHooksLoader.cpp:132CREATE_NO_WINDOWtoDETACHED_PROCESSHow it works
CreateNoWindow = falsewithUseShellExecute = false: child inherits parent console state. Since GVFS runs as a service with no console, child gets no console and no conhost.DETACHED_PROCESS(native): explicitly detaches from any console without allocating a new one.Verification
Conhost elimination confirmed
CreateNoWindow=true(old)CreateNoWindow=false(new)Benchmark (3 runs x 50 git.exe invocations)
For a prefetch spawning 20-50 git.exe processes, this eliminates ~380-960ms of pure conhost overhead per cycle.
Reference