On Thu, Oct 6, 2016 at 12:46 PM, Yan Seiner <[email protected]> wrote: > How does busybox handle multiple cpu cores? > > The 'standard' top will show multiples of 100%, so a 4 core hyperthreaded > cpu can go to 800% utilization. > > Busybox seems to cap at 100%. I have a dual core cpu, and I'm not seeing > utilization above 100%. As the one process I have is single-threaded, I'm > confused as to what's happening. A single process on a dual core machine > should take 100% in which case other processes could use the "other" 100%, > or if it is normalized to 100% for all cores, it should not take more than > 50%.
Yes. A different convention. The convention that single task does not ever use >100% CPU (IOW: that 100% means "all CPUs were running this task thereads all the time since last update) helps with output formatting: %CPU column can be only 4 chars wide and it's always enough, even one digit after decimal point fits there. Examples: " 0.0", "54.0", " 100" (needs no decimal point). If %CPU would be allowed to go up to NCPUS*100, on machines with more than 9 CPUs you need a wider column. With more than 99 CPUs, add one more char. Knights Landing single-socket machines today have 288 CPUs. [well, actually 304, if all 38 tiles are functional, but Intel doesn't sell such CPUs as of now - always disables at least 2 tiles] _______________________________________________ busybox mailing list [email protected] http://lists.busybox.net/mailman/listinfo/busybox
