On Mon, 20 Jan 2003, Michael Sternberg wrote: > Hello. > >From time to time I notice in output of /usr/bin/top that my system CPU > time jumps to nearly 90%. How can I know which task kernel performs ? > I'm looking for some kind of "top" for kernel.. Maybe some file in /proc > directory ?
please note that 'system' time will include the time spent by user-space processes, running in kernel mode. for example, if a process does a lot of disk I/O, then you'll see it is spending a lot of time in 'system' mode, and thus 'top' will show the 'system' time as non-zero. the same goes for other types of heavy I/O (networking, swapping, interrupt handling). without too much hasteling, you could use a few standard utilities ot help you debug problems. there is 'vmstat' (run it as 'vmstat 3' to refresh every 3 seconds, and ignore the first line of output. read the man page for more info). there is 'iostat' (similar, but concentrates on device I/O, like disks). you might also have 'sar'. in order to actually decipher the output of these programs, you should look at what they show you wihle the system is in 'silent' mode, and then compare that to what they show under various types of activities. then compare to other systems - otherwise, you'll have no idea what 'high ammount of context switches' is, or what ammount of interrupts per second makes the mahcine too slow... you need to know the capacity of your machine, in order to know if its saturated regarding activity of a given resource, or not (i.e. if its getting so many interrupts per second, that this comes on account of its ability to run user-space programs, etc). i don't suppose this will actually help you in the short run, but perhaps it will in the long run. if you manage to find a resource that gives 'proper numbers' for various types of hardware - let me know, please ;) will help me quite alot. -- guy "For world domination - press 1, or dial 0, and please hold, for the creator." -- nob o. dy ================================================================= To unsubscribe, send mail to [EMAIL PROTECTED] with the word "unsubscribe" in the message body, e.g., run the command echo unsubscribe | mail [EMAIL PROTECTED]
