top delay value
stephen at math.missouri.edu
Tue Jan 30 15:59:35 UTC 2007
Dan Nelson wrote:
> In the last episode (Jan 30), waldeck at gmx.de said:
>>An unprivileged user could waste all CPU time by setting a low delay
>>value in top (interactive or via -s).
> Are you sure? In 6.2 at least, "s0" in interactive mode results in a
> 1-second delay, and "top -s0" prints
> top: warning: seconds delay should be positive -- using default
You can run "top -s0" as root (not that this negates your point in any way).
Incidently, this is an excellent way to generate those "calcru going
backwards" errors, at least in some recent versions of FreeBSD. Just
run a highly threaded, CPU intensive job at the same time. I did this
on SMP systems, so I don't know if it also does this on non-SMP systems.
On versions of FreeBSD 5.x I was able to induce kernel panics, the
likes of which produced useless core dumps, but this seems to have been
fixed with more recent versions.
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