Tracing getpid():

• Disassembly of getpid() from libc.a. [For comparison, a disassembly of read() from libc.a]
• entry.S from x86 Linux 1.2.11. On a system call (int $0x80), execution starts at ENTRY(system_call).
• Here is where control ends up after jumping to the address in the system call table.