HP-UX 11i Tuning and Performance

8.13. Expensive System Calls

The most expensive system calls from the standpoint of memory are fork(2) and exec(2), malloc(2), and mmap(2). Fork(2) and exec(2) require extensive new memory allocation for VAS/pregion structures; vfork(2) offers a partial remedy (see Section 8.5.1, “fork and vfork” on page 235).

Malloc(2) and mmap(2) also are expensive calls because they have a high amount of overhead per invocation, so calling them frequently can result in high CPU overhead.