sign. user is just time spend on user mode. sys is time spend on kernel mode. real is the real clock time. If your program is waiting for some thing(disk/network), or the system is running some other task. The the time spend on user is small than the real time. real time == user time only happen when kernel pretty much only schedule one process (taking 100% CPU) at the user space. SMP is a different story, in SMP case you can see user time > real time because running on two different processor.