The Samba-Bugzilla – Attachment 16118 Details for
Bug 14430
smbd-notifyd O(n*n) performance issue with n watches registered for the same folder
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Windows C program for reproducing the issue
ChangeNotify.cpp (text/plain), 3.15 KB, created by
YOUZHONG YANG
on 2020-07-07 15:42:27 UTC
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Description:
Windows C program for reproducing the issue
Filename:
MIME Type:
Creator:
YOUZHONG YANG
Created:
2020-07-07 15:42:27 UTC
Size:
3.15 KB
patch
obsolete
>#include <SDKDDKVer.h> >#include <windows.h> >#include <stdlib.h> >#include <stdio.h> >#include <tchar.h> > >void WatchDirectory(int); > >HANDLE *dwChangeHandles = NULL; >HANDLE *dwThreads = NULL; > >DWORD WINAPI ThreadProc(LPVOID); > >DWORD WINAPI ThreadProc(LPVOID lpParam) >{ > int index = (int)lpParam; > > WatchDirectory(index); > > return 0; >} > >void _tmain(int argc, TCHAR *argv[]) >{ > int how_many = 50; > int i; > DWORD status; > DWORD dwThreadID; > > if(argc < 2) > { > _tprintf(TEXT("Usage: %s <dir> [number]\n"), argv[0]); > _tprintf(TEXT(" Where number * 64 change notifications will be created and monitored for the same folder <dir>.\n")); > return; > } > > if (argc > 2) > how_many = _tstoi(argv[2]); > if (how_many <= 0) > how_many = 100; > _tprintf(TEXT("Monitoring %s - %d change notifications.\n"), argv[1], how_many * 64); > > dwChangeHandles = (HANDLE *)calloc(how_many * 64, sizeof(HANDLE)); > dwThreads = (HANDLE *)calloc(how_many, sizeof(HANDLE)); > > for (i = 0; i < how_many * 64; i++) { > dwChangeHandles[i] = FindFirstChangeNotification( > argv[1], // directory to watch > FALSE, // do not watch subtree > FILE_NOTIFY_CHANGE_FILE_NAME | FILE_NOTIFY_CHANGE_DIR_NAME | > FILE_NOTIFY_CHANGE_ATTRIBUTES | FILE_NOTIFY_CHANGE_SIZE | > FILE_NOTIFY_CHANGE_LAST_WRITE | FILE_NOTIFY_CHANGE_LAST_ACCESS | > FILE_NOTIFY_CHANGE_CREATION | FILE_NOTIFY_CHANGE_SECURITY); > if (dwChangeHandles[i] == INVALID_HANDLE_VALUE || dwChangeHandles[i] == NULL) > { > status = GetLastError(); > _tprintf(TEXT("ERROR: FindFirstChangeNotification failed. Error code %lu.\n"), status); > ExitProcess(status); > } > } > > for (i = 0; i < how_many; i++) { > dwThreads[i] = CreateThread( > NULL, // default security attributes > 0, // default stack size > (LPTHREAD_START_ROUTINE)ThreadProc, > (LPVOID)i, // no thread function arguments > 0, // default creation flags > &dwThreadID); // receive thread identifier > } > > status = WaitForMultipleObjects(how_many, dwThreads, > TRUE, INFINITE); > > for (i = 0; i < how_many * 64; i++) { > FindCloseChangeNotification(dwChangeHandles[i]); > } > > free((void*)dwChangeHandles); > free((void*)dwThreads); > > ExitProcess(0); >} > >void WatchDirectory(int index) >{ > DWORD dwWaitStatus; > int idx; > DWORD status; > DWORD dwTotal = 0; > int i; > BOOL bWaitAll = false; > > while (TRUE) > { > dwWaitStatus = WaitForMultipleObjects(64, &dwChangeHandles[index * 64], > bWaitAll, INFINITE); > if (dwWaitStatus == WAIT_FAILED || (dwWaitStatus >= (WAIT_OBJECT_0 + 64))) { > _tprintf(TEXT("ERROR: [%d] WaitForMultipleObjects returned %lu.\n"), index, dwWaitStatus); > return; > } > > idx = dwWaitStatus - WAIT_OBJECT_0; > dwTotal++; > > //_tprintf(TEXT("Thread %04d - CNH %d idx %d total %lu\n"), index, index * 64 + idx, idx, dwTotal); > > if (FindNextChangeNotification(dwChangeHandles[index * 64 + idx]) == FALSE) > { > status = GetLastError(); > _tprintf(TEXT("ERROR: [%d] FindNextChangeNotification function failed. Error code %lu\n"), index, status); > return; > } > } >}
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bug 14430
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