Rick, Etienne, Thanks for your feedback. From it (and my ignorance ;-) follows another question. For performance measuring purposes, I think it is useful to compare interrupts and CPU context switches in a non tickless kernel. I.e., if the amount of Interrupts is much higher than the amount of context switches, that is good. If the difference is not very big, a lot of CPU time is wasted on context switches. Now that I don't have ticks anymore, I can't see the relation between interrupts and context switches anymore. Are you aware of any other way of seeing them? I used to use vmstat -s to display this information.
Thanks, Sander On Mon, 2008-08-11 at 08:40 -0500, Rick Clark wrote: > On Saturday 09 August 2008 10:36:41 Sander van Vugt wrote: > > Hi List, > > > > I notices something I don't understand in the vmstat -s output. In other > > Linux distributions I know, the amount of interrupts is always much > > higher than the amount of context switches. As far as I know, that from > > the operating system perspective is also what you would expect, as a > > context switch needs a timer interrupt to do its work. Now when I do > > vmstat -s on Ubuntu Server 8.04, the amount of context switches is about > > 5 times as high as the amount of interrupts, where I would expect the > > exact opposite. Can anyone explain this? Is this a specific Ubuntu feature? > > > > Thanks, > > Sander > > Sander, > > I also believe that this is the tickless kernel. Could you verify that you > are fewer interrupts and not more context switches then expected. > > Rick Clark > Manager, Ubuntu Server Team -- ubuntu-server mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-server More info: https://wiki.ubuntu.com/ServerTeam
