Date: Fri, 18 Aug 2006 18:31:15 +1000 From: Peter Jeremy <peterjeremy@optushome.com.au> To: Bill LeFebvre <bill@lefebvre.org> Cc: freebsd-stable@freebsd.org Subject: Re: TOP shows above 100% WCPU usage Message-ID: <20060818083115.GB732@turion.vk2pj.dyndns.org> In-Reply-To: <44E483C0.6050209@lefebvre.org> References: <44E1F796.5070105@rogers.com> <20060815172728.GB88051@dan.emsphone.com> <44E204C0.60806@rogers.com> <44E3FE61.6060800@lefebvre.org> <20060817144110.GB88424@dan.emsphone.com> <44E483C0.6050209@lefebvre.org>
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On Thu, 2006-Aug-17 10:57:04 -0400, Bill LeFebvre wrote:
>Dan Nelson wrote:
>>I just built top-3.6 on such a system, though, and it does report a
>>simple "main(){for(;;);}" process as consuming 100 %CPU. Maybe you're
>>thinking of Solaris's own prstat command?
>
>Heh. I released 3.6 with new SunOS code that didn't adjust for number of
>cpus, and someone flagged the behavior as a bug. So you're right: 3.6
>doesn't do it this way. But 3.5 did, and it seems at least some people
>prefer it that way.
I actually prefer this new behaviour. One of my major uses of top is
identifying processes that are spinning for one reason or another.
Having a process show up as 99-100% is quite obvious and I can then
look closer to see if that process is validly using 100% CPU or not.
Having a process using 3.1% CPU (on a 32-CPU system) would be far less
obvious. (In my case, I'm scanning instaneous top outputs from ~60
hosts so I don't want to have to study each output too closely).
To my way of thinking, %CPU is a percentage of a single CPU. If a
box has 32 CPUs, then maximum load is 3200% of a single CPU.
I think there are probably equally good rationales for each approach.
Probably the best situation is a flag to toggle between the two
approaches, together with two different titles to make it clear which
is being used.
--
Peter Jeremy
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