On Sat, Oct 13, 2007 at 03:31:09PM +0200, Philipp Kempgen wrote: > Tzafrir Cohen wrote: > > > The loadavg is the average number of threads[0] ready to run (or running). > > To me it seems that there are important differences between > systems, especially Linux/Unix, as of which of the states in > following are counted in: > - running (i.e. using the CPU) > - runnable (i.e. waiting for their turn) > - uninterruptible sleep (i.e. waiting for disk/network I/O)
Load average is for both "running" and "runnable". The test is simple: a 100% cpu loop is easy to create (while :; do :; done in bourne shells such as bash, pick your favorite environment. Run as many as you want). Strangely enough in Linux the load avarage includes also processes in a "uninterruptable sleep" (state "D" in top and ps, as opposed to "S", which is where processes normally are). Processes staying long in uninterruptable sleep usually mean a trouble of some sort. > > Without knowing how your kernel calculates the loadavg the > usefulness of this value is very limited. > > > We are all well > > familiar with a single CPU and single core systems. In those systems > > only one thread can execute at each time. If the load average is greater > > than 1 it means that there on the average[1] at least one process > > waiting for the CPU and not getting executed immediately. > > So what you're implying is that only runnable (i.e. waiting) > threads are counted, not running threads. Running threads sure are counted. > The question is if there are any differences on a multi-CPU > system. Waiting threads would still be waiting threads, no > matter how many CPUs /could/ run the thread /if they were idle/. > Is that correct? > > The mistake people often seem to make is to assume that > loadavg == cpu usage. It is a good indication. Even a better indicaton to the ammount of threads ("processes") starved for CPU time. -- Tzafrir Cohen icq#16849755 jabber:[EMAIL PROTECTED] +972-50-7952406 mailto:[EMAIL PROTECTED] http://www.xorcom.com iax:[EMAIL PROTECTED]/tzafrir _______________________________________________ --Bandwidth and Colocation Provided by http://www.api-digital.com-- asterisk-users mailing list To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users