Thanks a lot Andy, one this that is bothering me is, Say if the load of procedures by executing the command mentioned by you is as follows in descending order.... 2604 __geneic_copy_to_user 40.6875 1705 csum_patrial_copy_generic 6.8750 370 __generic_copy_from_user 3.75 764 do_annonymous_page 3.1754 176 handle_IRQ_event 1.5714 31 remove_wait_queue 0.96 the list goes on are these procedures condidered as load on the CPU? how much of a load ? very high, high, moderate ..... If you can throw some light on this, it will be great. Thanking You Shesha On Mon, 14 Apr 2003, Andy Pfiffer wrote: > On Mon, 2003-04-14 at 15:17, Shesha@asu.edu wrote: > > Hello Linux ppl, > > > > I have copuple of questions, I request you to share the information if you > > know .... > > I have a partial answer. > > > -- > > 1 > > -- > > In the readprofile man page load=(# of clk ticks) / (length of the procedure) > > > > What does "length of procedure" means. > > My understanding after a quick read of the source is that "length of the > procedure" means the length, in bytes, of the function. For most > architectures, there is not a correlation between lines of code in > assembler and number of executable bytes. > > On ARM all instructions are 4 bytes long (not counting "Thumb" style > instruction encoding), but that does not mean 1 line of assembler source > code is equal to 4 bytes worth of instructions. > > As far as I can tell, the "length of the procedure" is determined by the > difference between sucessive symbols found in System.map: > > . > . > . > c0109414 T sys_fork > c010943c T sys_clone > c0109474 T sys_vfork > c01094a0 T sys_execve > . > . > . > > sys_clone(), on my system, is 56 bytes long, including any alignment > padding (0xc0109474-0xc010943c = 56). > > > > > Does that mean the # of ASM lines of > > the procedure code? What is the units of the load. It cannot be %. because > > ----------------------------------------------------------- > > 152495 default_idle 3176.9792 > > ----------------------------------------------------------- > > the above line indicates, more than 100% of times CPU is idle. This cannot > > happen. > > It is not a percentage. The value is computed by: > > "load" = ticks_attributed_to_the_proc / length_of_proc > > >From your example above: > > 3176.9792 = 152495 / length_of_proc > > therefore length_of_proc = 48 bytes. 48 looks reasonable when cross > checked with my x86 system (default_idle() is 52 bytes long on my > system). > > > > What value of the procedure load is considered to be a potential CPU > > intensive procedure/ high load procedure. > > There is no magic number. However, from the readprofile man page, some > likely "high load" candidates could be found by: > > readprofile | sort -nr +2 | head -20 > > > Regards, > Andy > > -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/
