> On Thu, 2003-10-23 at 01:55, Joakim Tjernlund wrote: > > I did a kernel profile(included below) of the bootup of my custom MPC862 > > board and I > > noticed that __restore_flags gets a very high count. I am suprised that > > such a small > > assembler routine gets such a high count. __cli, _save_flags_ptr and __sti > > are much lower. > > A small test program with a tight select loop on fds 0,1 or 2 also makes > > __restore_flags > > go wild. > > Anyone know why? > > > > Simple: when interrupts are off (typically after a __save_flags), > there can't be any profiling interrupts. As soon as you restore > the interrupts (_restore_flags), the interrupt used for profiling > will fire.
I see, thanks. Now I wonder what keeps interrupts off for so long and what those nops are doing in __restore_flags. Jocke ** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/
