Anchor Messages

When a software trace is lengthy it is useful to partition it into several regions based on a sequence of Anchor Messages. The choice of them can be determined by a Vocabulary Index (Volume 4, page 349) or an Adjoint Thread of Activity (page 283). For example, an ETW trace with almost 900,000 messages recorded during a desktop connection for 6 minutes can be split into 14 segments by the adjoint thread of DLL_PROCESS_ATTACH message (the message was generated by DllMain of an injected module, not shown in the trace output for formatting clarity):

#      PID  TID  Time         Message
24226  2656 3480 10:41:05.774 AppA.exe: DLL_PROCESS_ATTACH
108813 4288 4072 10:41:05.774 AppB.exe: DLL_PROCESS_ATTACH
112246 4180 3836 10:41:05.940 DllHost.exe: DLL_PROCESS_ATTACH
135473 2040 3296 10:41:12.615 AppC.exe: DLL_PROCESS_ATTACH
694723 1112 1992 10:44:23.393 AppD.exe: DLL_PROCESS_ATTACH
703962 5020 1080 10:44:42.014 DllHost.exe: DLL_PROCESS_ATTACH
705511 4680 3564 10:44:42.197 DllHost.exe: DLL_PROCESS_ATTACH
705891 1528 2592 10:44:42.307 regedit.exe: DLL_PROCESS_ATTACH
785231 2992 4912 10:45:26.516 AppE.exe: DLL_PROCESS_ATTACH
786523 3984 1156 10:45:26.605 powershell.exe: DLL_PROCESS_ATTACH
817979 4188 4336 10:45:48.707 wermgr.exe: DLL_PROCESS_ATTACH
834875 3976 1512 10:45:52.342 LogonUI.exe: DLL_PROCESS_ATTACH
835229 4116 3540 10:45:52.420 AppG.exe: DLL_PROCESS_ATTACH