Top not showing cpu usage even remotely accurately
smithi at nimnet.asn.au
Thu Aug 10 16:24:35 UTC 2006
On Thu, 10 Aug 2006, Chuck Swiger wrote:
> Ian Smith wrote:
> > But since running 5.x (5.5-STABLE since 1st Aug) top can show 0.0% idle
> > but the cpu usages shown don't add up to much of a fraction of 100%.
> [ ... ]
> > Any ideas why top hasn't much of a clue about what's consuming cpu?
> Sure, if you're running a parallel make, that will be starting up lots of
> short-lived compiler processes which exit quickly; top can only display the
> CPU load for those processes which are still running at the time it samples
> the system.
Spot on, thanks Chuck. lastcomm showed a couple of thousand processes
run per minute during several hours of 'make index'; /var/account/acct
was nearly 10MB for that time. Only one gcc but lots of sh, perl, grep,
awk, sed and such each running < 1 second, being a texty sort of job.
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