On 2009-Nov-11 23:22:36 +1100, Bruce Evans <brde@optusnet.com.au> wrote:
>On Fri, 6 Nov 2009, Xin LI wrote:
>> Will it sound reasonable to divide pcpu by ncpu and cap the number at 100?
>
>I don't like that. It would break scripts even more than units changes.
>It is hard for users to interpret too. Suddenly, processes taking
>100% of 1 CPU would take 12.5% of 8 CPUs on a system with 8 CPUs, and
>different %CPU on systems with a different number of CPUs.
Solaris does this. I found it particularly annoying for identifying
spinning, single-threaded processes - it's not as immediately obvious
that 1.6% CPU means a spinning process on a T5000, and the granularity
gets worse.
>Just print %CPU in %4.0f format when it is >= 99.5 (or whatever rounds
>to 100.0). This works up to 999.5 %CPU.
Actually, %4.0f works up to 9999.5 %CPU because there's no '.' in the
result. I think this is an excellent solution. And since FreeBSD
currently has a hard limit of 64 CPUs, it's unlikely to be exceeded
for a while.
--
Peter Jeremy
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