The following are examples of py_syscolors.d. This is a simple script to trace the flow of Python functons and system calls made, and renders the output in color ("colour") using terminal escape sequences (which you can tweak by modifying the script). Here it traces the example program, Code/Python/func_abc.py. WARNING: This output is full of terminal escape sequences, so if you are trying to view this through an editor or web browser - it may look awful. Try viewing this using "more" (although, depending on your terminal, it still may look awful). # py_syscolors.d -c ./func_abc.py C PID DELTA(us) FILE:LINE TYPE -- NAME 0 145544 2 ":- syscall -> munmap 0 145544 34 ":- syscall <- munmap 0 145544 56 ":- syscall -> mmap 0 145544 19 ":- syscall <- mmap 0 145544 42 ":- syscall -> setcontext 0 145544 10 ":- syscall <- setcontext 0 145544 9 ":- syscall -> getrlimit 0 145544 10 ":- syscall <- getrlimit 0 145544 9 ":- syscall -> getpid 0 145544 8 ":- syscall <- getpid 0 145544 68 ":- syscall -> setcontext 0 145544 8 ":- syscall <- setcontext 0 145544 121 ":- syscall -> sigpending 0 145544 9 ":- syscall <- sigpending 0 145544 172 ":- syscall -> open64 0 145544 114 ":- syscall <- open64 0 145544 14 ":- syscall -> ioctl 0 145544 28209 ":- syscall <- ioctl 0 145544 285 ":- syscall -> close 0 145544 31 ":- syscall <- close 0 145544 41 ":- syscall -> open64 0 145544 88 ":- syscall <- open64 0 145544 9 ":- syscall -> ioctl 0 145544 293 ":- syscall <- ioctl 0 145544 11 ":- syscall -> close 0 145544 13 ":- syscall <- close 0 145544 1182 ":- syscall -> sysi86 0 145544 12 ":- syscall <- sysi86 0 145544 143 ":- syscall -> sysconfig 0 145544 53 ":- syscall <- sysconfig 0 145544 95 ":- syscall -> open64 0 145544 22 ":- syscall <- open64 0 145544 11 ":- syscall -> fstat64 0 145544 10 ":- syscall <- fstat64 0 145544 31 ":- syscall -> ioctl 0 145544 42 ":- syscall <- ioctl 0 145544 24 ":- syscall -> brk 0 145544 10 ":- syscall <- brk 0 145544 8 ":- syscall -> brk 0 145544 17 ":- syscall <- brk 0 145544 30 ":- syscall -> sysconfig 0 145544 8 ":- syscall <- sysconfig 0 145544 32 ":- syscall -> brk 0 145544 7 ":- syscall <- brk 0 145544 8 ":- syscall -> brk [... 1400 lines truncated ...] 0 145544 8 ":- syscall -> fstat64 0 145544 7 ":- syscall <- fstat64 0 145544 11 ":- syscall -> read 0 145544 8 ":- syscall <- read 0 145544 29 ":- syscall -> brk 0 145544 8 ":- syscall <- brk 0 145544 8 ":- syscall -> brk 0 145544 10 ":- syscall <- brk 0 145544 393 ":- syscall -> llseek 0 145544 8 ":- syscall <- llseek 0 145544 9 ":- syscall -> close 0 145544 9 ":- syscall <- close 0 145544 14 aliases.py:17 func -> ? 0 145544 57 aliases.py:18 func <- ? 0 145544 20 ":- syscall -> llseek 0 145544 8 ":- syscall <- llseek 0 145544 8 ":- syscall -> close 0 145544 8 ":- syscall <- close 0 145544 15 __init__.py:43 func -> CodecRegistryError 0 145544 12 __init__.py:45 func <- CodecRegistryError 0 145544 26 __init__.py:145 func <- ? 0 145544 18 ":- syscall -> llseek 0 145544 8 ":- syscall <- llseek 0 145544 8 ":- syscall -> close 0 145544 9 ":- syscall <- close 0 145544 13 __init__.py:69 func -> search_function 0 145544 14 __init__.py:47 func -> normalize_encoding 0 145544 18 __init__.py:67 func <- normalize_encoding 0 145544 29 ":- syscall -> stat64 0 145544 20 ":- syscall <- stat64 0 145544 10 ":- syscall -> open64 0 145544 18 ":- syscall <- open64 0 145544 8 ":- syscall -> open64 0 145544 17 ":- syscall <- open64 0 145544 8 ":- syscall -> open64 0 145544 18 ":- syscall <- open64 0 145544 9 ":- syscall -> fstat64 0 145544 8 ":- syscall <- fstat64 0 145544 8 ":- syscall -> open64 0 145544 18 ":- syscall <- open64 0 145544 8 ":- syscall -> fstat64 0 145544 8 ":- syscall <- fstat64 0 145544 9 ":- syscall -> fstat64 0 145544 7 ":- syscall <- fstat64 0 145544 8 ":- syscall -> ioctl 0 145544 7 ":- syscall <- ioctl 0 145544 8 ":- syscall -> read 0 145544 19 ":- syscall <- read 0 145544 8 ":- syscall -> fstat64 0 145544 8 ":- syscall <- fstat64 0 145544 8 ":- syscall -> read 0 145544 8 ":- syscall <- read 0 145544 22 ":- syscall -> llseek 0 145544 8 ":- syscall <- llseek 0 145544 8 ":- syscall -> close 0 145544 9 ":- syscall <- close 0 145544 12 ascii.py:8 func -> ? 0 145544 16 ascii.py:13 func -> Codec 0 145544 12 ascii.py:18 func <- Codec 0 145544 22 ascii.py:20 func -> StreamWriter 0 145544 11 ascii.py:21 func <- StreamWriter 0 145544 20 ascii.py:23 func -> StreamReader 0 145544 11 ascii.py:24 func <- StreamReader 0 145544 32 ascii.py:26 func -> StreamConverter 0 145544 12 ascii.py:29 func <- StreamConverter 0 145544 21 ascii.py:33 func <- ? 0 145544 17 ":- syscall -> llseek 0 145544 8 ":- syscall <- llseek 0 145544 8 ":- syscall -> close 0 145544 8 ":- syscall <- close 0 145544 13 ascii.py:33 func -> getregentry 0 145544 12 ascii.py:35 func <- getregentry 0 145544 34 __init__.py:142 func <- search_function 0 145544 23 ":- syscall -> ioctl 0 145544 42 ":- syscall <- ioctl 0 145544 11 ":- syscall -> ioctl 0 145544 9 ":- syscall <- ioctl 0 145544 12 ":- syscall -> readlink 0 145544 16 ":- syscall <- readlink 0 145544 20 ":- syscall -> resolvepath 0 145544 18 ":- syscall <- resolvepath 0 145544 12 ":- syscall -> getcwd 0 145544 20 ":- syscall <- getcwd 0 145544 27 ":- syscall -> ioctl 0 145544 8 ":- syscall <- ioctl 0 145544 14 ":- syscall -> llseek 0 145544 7 ":- syscall <- llseek 0 145544 8 ":- syscall -> fstat64 0 145544 8 ":- syscall <- fstat64 0 145544 8 ":- syscall -> fstat64 0 145544 7 ":- syscall <- fstat64 0 145544 8 ":- syscall -> ioctl 0 145544 7 ":- syscall <- ioctl 0 145544 8 ":- syscall -> read 0 145544 19 ":- syscall <- read 0 145544 9 ":- syscall -> llseek 0 145544 7 ":- syscall <- llseek 0 145544 8 ":- syscall -> llseek 0 145544 7 ":- syscall <- llseek 0 145544 12 ":- syscall -> read 0 145544 13 ":- syscall <- read 0 145544 105 ":- syscall -> read 0 145544 9 ":- syscall <- read 0 145544 10 ":- syscall -> llseek 0 145544 7 ":- syscall <- llseek 0 145544 8 ":- syscall -> close 0 145544 9 ":- syscall <- close 0 145544 117 func_abc.py:3 func -> ? 0 145544 20 ":- syscall -> stat64 0 145544 15 ":- syscall <- stat64 0 145544 10 ":- syscall -> stat64 0 145544 13 ":- syscall <- stat64 0 145544 10 ":- syscall -> open64 0 145544 15 ":- syscall <- open64 0 145544 8 ":- syscall -> open64 0 145544 13 ":- syscall <- open64 0 145544 8 ":- syscall -> open64 0 145544 13 ":- syscall <- open64 0 145544 8 ":- syscall -> open64 0 145544 13 ":- syscall <- open64 0 145544 9 ":- syscall -> stat64 0 145544 13 ":- syscall <- stat64 0 145544 9 ":- syscall -> open64 0 145544 13 ":- syscall <- open64 0 145544 8 ":- syscall -> open64 0 145544 13 ":- syscall <- open64 0 145544 8 ":- syscall -> open64 0 145544 13 ":- syscall <- open64 0 145544 8 ":- syscall -> open64 0 145544 13 ":- syscall <- open64 0 145544 9 ":- syscall -> stat64 0 145544 15 ":- syscall <- stat64 0 145544 8 ":- syscall -> open64 0 145544 15 ":- syscall <- open64 0 145544 8 ":- syscall -> open64 0 145544 15 ":- syscall <- open64 0 145544 8 ":- syscall -> open64 0 145544 15 ":- syscall <- open64 0 145544 8 ":- syscall -> open64 0 145544 15 ":- syscall <- open64 0 145544 9 ":- syscall -> stat64 0 145544 17 ":- syscall <- stat64 0 145544 9 ":- syscall -> open64 0 145544 17 ":- syscall <- open64 0 145544 8 ":- syscall -> open64 0 145544 16 ":- syscall <- open64 0 145544 8 ":- syscall -> open64 0 145544 16 ":- syscall <- open64 0 145544 8 ":- syscall -> open64 0 145544 16 ":- syscall <- open64 0 145544 8 ":- syscall -> stat64 0 145544 17 ":- syscall <- stat64 0 145544 8 ":- syscall -> open64 0 145544 17 ":- syscall <- open64 0 145544 8 ":- syscall -> open64 0 145544 16 ":- syscall <- open64 0 145544 8 ":- syscall -> open64 0 145544 16 ":- syscall <- open64 0 145544 8 ":- syscall -> open64 0 145544 16 ":- syscall <- open64 0 145544 9 ":- syscall -> stat64 0 145544 17 ":- syscall <- stat64 0 145544 8 ":- syscall -> open64 0 145544 19 ":- syscall <- open64 0 145544 14 ":- syscall -> fstat64 0 145544 9 ":- syscall <- fstat64 0 145544 20 ":- syscall -> xstat 0 145544 18 ":- syscall <- xstat 0 145544 8 ":- syscall -> resolvepath 0 145544 19 ":- syscall <- resolvepath 0 145544 10 ":- syscall -> open 0 145544 19 ":- syscall <- open 0 145544 10 ":- syscall -> mmap 0 145544 21 ":- syscall <- mmap 0 145544 33 ":- syscall -> mmap 0 145544 13 ":- syscall <- mmap 0 145544 9 ":- syscall -> mmap 0 145544 16 ":- syscall <- mmap 0 145544 8 ":- syscall -> mmap 0 145544 11 ":- syscall <- mmap 0 145544 34 ":- syscall -> munmap 0 145544 11 ":- syscall <- munmap 0 145544 43 ":- syscall -> memcntl 0 145544 13 ":- syscall <- memcntl 0 145544 8 ":- syscall -> close 0 145544 9 ":- syscall <- close 0 145544 30 ":- syscall -> mprotect 0 145544 13 ":- syscall <- mprotect 0 145544 169 ":- syscall -> mprotect 0 145544 13 ":- syscall <- mprotect 0 145544 2 ":- syscall <- nosys 0 145544 280 ":- syscall -> open 0 145544 90 ":- syscall <- open 0 145544 154 ":- syscall -> lwp_exit 0 145544 0 ":- syscall <- nosys 0 145544 214 ":- syscall -> ioctl 0 145544 301 ":- syscall <- ioctl 0 145544 186 ":- syscall -> lwp_exit 0 145544 0 ":- syscall <- nosys 0 145544 210 ":- syscall -> close 0 145544 18 ":- syscall <- close 0 145544 146 ":- syscall -> lwp_exit 0 145544 1 ":- syscall <- nosys 0 145544 208 ":- syscall -> open 0 145544 73 ":- syscall <- open 0 145544 151 ":- syscall -> lwp_exit 0 145544 0 ":- syscall <- nosys 0 145544 209 ":- syscall -> ioctl 0 145544 45 ":- syscall <- ioctl 0 145544 171 ":- syscall -> lwp_exit 0 145544 1 ":- syscall <- nosys 0 145544 194 ":- syscall -> close 0 145544 17 ":- syscall <- close 0 145544 145 ":- syscall -> lwp_exit 0 145544 0 ":- syscall <- nosys 0 145544 203 ":- syscall -> open 0 145544 63 ":- syscall <- open 0 145544 150 ":- syscall -> lwp_exit 0 145544 0 ":- syscall <- nosys 0 145544 209 ":- syscall -> ioctl 0 145544 280 ":- syscall <- ioctl 0 145544 185 ":- syscall -> lwp_exit 0 145544 0 ":- syscall <- nosys 0 145544 193 ":- syscall -> close 0 145544 17 ":- syscall <- close 0 145544 145 ":- syscall -> lwp_exit 0 145544 1 ":- syscall <- nosys 0 145544 230 ":- syscall -> open 0 145544 82 ":- syscall <- open 0 145544 151 ":- syscall -> lwp_exit 0 145544 0 ":- syscall <- nosys 0 145544 210 ":- syscall -> ioctl 0 145544 45 ":- syscall <- ioctl 0 145544 171 ":- syscall -> lwp_exit 0 145544 1 ":- syscall <- nosys 0 145544 195 ":- syscall -> close 0 145544 18 ":- syscall <- close 0 145544 145 ":- syscall -> lwp_exit 0 145544 1 ":- syscall <- nosys 0 145544 204 ":- syscall -> open 0 145544 64 ":- syscall <- open 0 145544 149 ":- syscall -> lwp_exit 0 145544 0 ":- syscall <- nosys 0 145544 208 ":- syscall -> ioctl 0 145544 283 ":- syscall <- ioctl 0 145544 184 ":- syscall -> lwp_exit 0 145544 1 ":- syscall <- nosys 0 145544 192 ":- syscall -> close 0 145544 17 ":- syscall <- close 0 145544 146 ":- syscall -> lwp_exit 0 145544 0 ":- syscall <- nosys 0 145544 209 ":- syscall -> open 0 145544 72 ":- syscall <- open 0 145544 150 ":- syscall -> lwp_exit 0 145544 0 ":- syscall <- nosys 0 145544 209 ":- syscall -> ioctl 0 145544 45 ":- syscall <- ioctl 0 145544 171 ":- syscall -> lwp_exit 0 145544 1 ":- syscall <- nosys 0 145544 198 ":- syscall -> close 0 145544 17 ":- syscall <- close 0 145544 860 ":- syscall -> lwp_exit 0 145544 1 ":- syscall <- nosys 0 145544 223 ":- syscall -> open 0 145544 83 ":- syscall <- open 0 145544 151 ":- syscall -> lwp_exit 0 145544 0 ":- syscall <- nosys 0 145544 213 ":- syscall -> ioctl 0 145544 281 ":- syscall <- ioctl 0 145544 187 ":- syscall -> lwp_exit 0 145544 0 ":- syscall <- nosys 0 145544 196 ":- syscall -> close 0 145544 19 ":- syscall <- close 0 145544 145 ":- syscall -> lwp_exit 0 145544 1 ":- syscall <- nosys 0 145544 209 ":- syscall -> open 0 145544 69 ":- syscall <- open 0 145544 151 ":- syscall -> lwp_exit 0 145544 1 ":- syscall <- nosys 0 145544 213 ":- syscall -> ioctl 0 145544 47 ":- syscall <- ioctl 0 145544 173 ":- syscall -> lwp_exit 0 145544 1 ":- syscall <- nosys 0 145544 199 ":- syscall -> close 0 145544 18 ":- syscall <- close 0 145544 144 ":- syscall -> lwp_exit 0 145544 1 ":- syscall <- nosys 0 145544 212 ":- syscall -> open 0 145544 67 ":- syscall <- open 0 145544 149 ":- syscall -> lwp_exit 0 145544 0 ":- syscall <- nosys 0 145544 213 ":- syscall -> ioctl 0 145544 282 ":- syscall <- ioctl 0 145544 187 ":- syscall -> lwp_exit 0 145544 0 ":- syscall <- nosys 0 145544 197 ":- syscall -> close 0 145544 59 ":- syscall <- close 0 145544 637 ":- syscall -> lwp_exit 0 145544 1 ":- syscall <- nosys 0 145544 222 ":- syscall -> open 0 145544 80 ":- syscall <- open 0 145544 151 ":- syscall -> lwp_exit 0 145544 0 ":- syscall <- nosys 0 145544 214 ":- syscall -> ioctl 0 145544 47 ":- syscall <- ioctl 0 145544 172 ":- syscall -> lwp_exit 0 145544 1 ":- syscall <- nosys 0 145544 199 ":- syscall -> close 0 145544 19 ":- syscall <- close 0 145544 144 ":- syscall -> lwp_exit 0 145544 0 ":- syscall <- nosys 0 145544 205 ":- syscall -> open 0 145544 62 ":- syscall <- open 0 145544 150 ":- syscall -> lwp_exit 0 145544 0 ":- syscall <- nosys 0 145544 211 ":- syscall -> ioctl 0 145544 304 ":- syscall <- ioctl 0 145544 190 ":- syscall -> lwp_exit 0 145544 1 ":- syscall <- nosys 0 145544 197 ":- syscall -> close 0 145544 17 ":- syscall <- close 0 145544 145 ":- syscall -> lwp_exit 0 145544 1 ":- syscall <- nosys 0 145544 211 ":- syscall -> open 0 145544 70 ":- syscall <- open 0 145544 149 ":- syscall -> lwp_exit 0 145544 0 ":- syscall <- nosys 0 145544 211 ":- syscall -> ioctl 0 145544 46 ":- syscall <- ioctl 0 145544 172 ":- syscall -> lwp_exit 0 145544 2 ":- syscall <- nosys 0 145544 260 ":- syscall -> close 0 145544 26 ":- syscall <- close 0 145544 160 ":- syscall -> lwp_exit 0 145544 1 ":- syscall <- nosys 0 145544 207 ":- syscall -> open 0 145544 79 ":- syscall <- open 0 145544 151 ":- syscall -> lwp_exit 0 145544 0 ":- syscall <- nosys 0 145544 216 ":- syscall -> ioctl 0 145544 274 ":- syscall <- ioctl 0 145544 187 ":- syscall -> lwp_exit 0 145544 0 ":- syscall <- nosys 0 145544 195 ":- syscall -> close 0 145544 17 ":- syscall <- close 0 145544 145 ":- syscall -> lwp_exit 0 145544 1 ":- syscall <- nosys 0 145544 211 ":- syscall -> open 0 145544 70 ":- syscall <- open 0 145544 149 ":- syscall -> lwp_exit 0 145544 0 ":- syscall <- nosys 0 145544 214 ":- syscall -> ioctl 0 145544 48 ":- syscall <- ioctl 0 145544 173 ":- syscall -> lwp_exit 0 145544 1 ":- syscall <- nosys 0 145544 201 ":- syscall -> close 0 145544 17 ":- syscall <- close 0 145544 145 ":- syscall -> lwp_exit 0 145544 1 ":- syscall <- nosys 0 145544 211 ":- syscall -> open 0 145544 65 ":- syscall <- open 0 145544 150 ":- syscall -> lwp_exit 0 145544 0 ":- syscall <- nosys 0 145544 213 ":- syscall -> ioctl 0 145544 324 ":- syscall <- ioctl 0 145544 342 ":- syscall -> lwp_exit 0 145544 1 ":- syscall <- nosys 0 145544 203 ":- syscall -> close 0 145544 19 ":- syscall <- close 0 145544 145 ":- syscall -> lwp_exit 0 145544 1 ":- syscall <- nosys 0 145544 213 ":- syscall -> open 0 145544 76 ":- syscall <- open 0 145544 150 ":- syscall -> lwp_exit 0 145544 0 ":- syscall <- nosys 0 145544 214 ":- syscall -> ioctl 0 145544 48 ":- syscall <- ioctl 0 145544 174 ":- syscall -> lwp_exit 0 145544 0 ":- syscall <- nosys 0 145544 198 ":- syscall -> close 0 145544 18 ":- syscall <- close 0 145544 146 ":- syscall -> lwp_exit 0 145544 1 ":- syscall <- nosys 0 145544 206 ":- syscall -> open 0 145544 63 ":- syscall <- open 0 145544 150 ":- syscall -> lwp_exit 0 145544 0 ":- syscall <- nosys 0 145544 213 ":- syscall -> ioctl 0 145544 272 ":- syscall <- ioctl 0 145544 185 ":- syscall -> lwp_exit 0 145544 0 ":- syscall <- nosys 0 145544 194 ":- syscall -> close 0 145544 17 ":- syscall <- close 0 145544 146 ":- syscall -> lwp_exit 0 145544 1 ":- syscall <- nosys 0 145544 213 ":- syscall -> open 0 145544 70 ":- syscall <- open 0 145544 151 ":- syscall -> lwp_exit 0 145544 0 ":- syscall <- nosys 0 145544 214 ":- syscall -> ioctl 0 145544 47 ":- syscall <- ioctl 0 145544 173 ":- syscall -> lwp_exit 0 145544 1 ":- syscall <- nosys 0 145544 236 ":- syscall -> close 0 145544 23 ":- syscall <- close 0 145544 156 ":- syscall -> lwp_exit 0 145544 0 ":- syscall <- nosys 0 145544 210 ":- syscall -> open 0 145544 76 ":- syscall <- open 0 145544 150 ":- syscall -> lwp_exit 0 145544 0 ":- syscall <- nosys 0 145544 214 ":- syscall -> ioctl 0 145544 276 ":- syscall <- ioctl 0 145544 187 ":- syscall -> lwp_exit 0 145544 1 ":- syscall <- nosys 0 145544 197 ":- syscall -> close 0 145544 17 ":- syscall <- close 0 145544 145 ":- syscall -> lwp_exit 0 145544 1 ":- syscall <- nosys 0 145544 211 ":- syscall -> open 0 145544 71 ":- syscall <- open 0 145544 149 ":- syscall -> lwp_exit 0 145544 0 ":- syscall <- nosys 0 145544 214 ":- syscall -> ioctl 0 145544 47 ":- syscall <- ioctl 0 145544 172 ":- syscall -> lwp_exit 0 145544 1 ":- syscall <- nosys 0 145544 199 ":- syscall -> close 0 145544 19 ":- syscall <- close 0 145544 144 ":- syscall -> lwp_exit 0 145544 0 ":- syscall <- nosys 0 145544 210 ":- syscall -> open 0 145544 64 ":- syscall <- open 0 145544 150 ":- syscall -> lwp_exit 0 145544 0 ":- syscall <- nosys 0 145544 212 ":- syscall -> ioctl 0 145544 297 ":- syscall <- ioctl 0 145544 522 ":- syscall -> lwp_exit 0 145544 1 ":- syscall <- nosys 0 145544 210 ":- syscall -> close 0 145544 21 ":- syscall <- close 0 145544 146 ":- syscall -> lwp_exit 0 145544 1 ":- syscall <- nosys 0 145544 213 ":- syscall -> open 0 145544 79 ":- syscall <- open 0 145544 151 ":- syscall -> lwp_exit 0 145544 0 ":- syscall <- nosys 0 145544 213 ":- syscall -> ioctl 0 145544 47 ":- syscall <- ioctl 0 145544 173 ":- syscall -> lwp_exit 0 145544 1 ":- syscall <- nosys 0 145544 201 ":- syscall -> close 0 145544 19 ":- syscall <- close 0 145544 144 ":- syscall -> lwp_exit 0 145544 91667 ":- syscall -> munmap 0 145544 34 ":- syscall <- munmap 0 145544 65 ":- syscall -> gtime 0 145544 9 ":- syscall <- gtime 0 145544 13 ":- syscall -> open 0 145544 42 ":- syscall <- open 0 145544 10 ":- syscall -> fstat64 0 145544 9 ":- syscall <- fstat64 0 145544 8 ":- syscall -> read 0 145544 31 ":- syscall <- read 0 145544 9 ":- syscall -> close 0 145544 11 ":- syscall <- close 0 145544 65 ":- syscall -> llseek 0 145544 9 ":- syscall <- llseek 0 145544 8 ":- syscall -> close 0 145544 9 ":- syscall <- close 0 145544 25 func_abc.py:14 func -> func_a 0 145544 24 ":- syscall -> ioctl 0 145544 9 ":- syscall <- ioctl 0 145544 8 ":- syscall -> fstat64 0 145544 8 ":- syscall <- fstat64 0 145544 9 ":- syscall -> fstat64 0 145544 7 ":- syscall <- fstat64 0 145544 40 ":- syscall -> pollsys 0 145544 1009424 ":- syscall <- pollsys 0 145544 35 func_abc.py:9 func -> func_b 0 145544 40 ":- syscall -> pollsys 0 145544 1009681 ":- syscall <- pollsys 0 145544 36 func_abc.py:5 func -> func_c 0 145544 41 ":- syscall -> pollsys Function A Function B Function C 0 145544 1000116 ":- syscall <- pollsys 0 145544 34 func_abc.py:7 func <- func_c 0 145544 28 func_abc.py:12 func <- func_b 0 145544 14 func_abc.py:17 func <- func_a 0 145544 14 func_abc.py:19 func <- ? 0 145544 26 ":- syscall -> sigaction 0 145544 15 ":- syscall <- sigaction 0 145544 1150 ":- syscall -> write 0 145544 21 ":- syscall <- write 0 145544 212 ":- syscall -> open64 0 145544 116 ":- syscall <- open64 0 145544 11 ":- syscall -> ioctl 0 145544 24 ":- syscall <- ioctl 0 145544 10 ":- syscall -> close 0 145544 16 ":- syscall <- close 0 145544 8 ":- syscall -> open64 0 145544 32 ":- syscall <- open64 0 145544 9 ":- syscall -> ioctl 0 145544 169 ":- syscall <- ioctl 0 145544 10 ":- syscall -> close 0 145544 12 ":- syscall <- close 0 145544 62 ":- syscall -> rexit Here you can see the output showing the path the script follows as it is executed. 0 145544 35 func_abc.py:9 func -> func_b 0 145544 40 ":- syscall -> pollsys 0 145544 1009681 ":- syscall <- pollsys 0 145544 36 func_abc.py:5 func -> func_c This excerpt shows line 9 of the script executing. It makes a pollsys syscall in order to fulfill the request to sleep for one second, returns and then goes to line 5. Checking the logic flow of the example program, this makes sense.