Date: Sun, 11 Apr 1999 19:45:39 -0400 (EDT) From: Brian Feldman <green@unixhelp.org> To: Kevin Day <toasty@home.dragondata.com> Cc: Warner Losh <imp@harmony.village.org>, dillon@apollo.backplane.com, hasty@rah.star-gate.com, dv@dv.ru, freebsd-current@FreeBSD.ORG Subject: Re: DoS from local users (fwd) Message-ID: <Pine.BSF.4.05.9904111941540.34469-100000@janus.syracuse.net> In-Reply-To: <199904112247.RAA04823@home.dragondata.com>
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On Sun, 11 Apr 1999, Kevin Day wrote:
> > In message <199904102057.PAA27724@home.dragondata.com> Kevin Day writes:
> > : i.e. uid 1001 starts 40 processes eating as much cpu as they can. Then uid
> > : 1002 starts up one process. Uid 1002's process gets 50% cpu, and uid 1001's
> > : 40 processes get 50% cpu shared between them.
> >
> > I've seen some experimental patches in the past that try to do just
> > this. However, there are some problems. What if uid 1002's process
> > does a sleep. Should the 40 processes that 1001 just get 50% of the
> > cpu? Or should there be other limits. It turns into an interesting
> > research problem in a hurry.
> >
> > Warner
> >
>
> I was thinking essentially just processes in the RUN state get applied to
> this. If the cpu would otherwise be sitting idle, by all means give it to
> someone. But, if two users have processes running, just because one user has
> 50 processes doesn't mean it should get 50x the cpu as one user who has one
> process running. If a process is in sleep or blocked(select, IO, whatever),
> it's taken out of consideration for the cpu, and the full cpu is given to
> those processes that actually have work to do.
>
>
> At least, that's my take on it.
>
> I run into this problem daily, and i get enough user complains of "User x
> has 50 processes running, eating as much cpu as they can, my compile just
> took 15 minutes".
"What was their user name again?"
*click xterm click*
ps aux | grep ^user | wc -l
"Hmm, you're right, fifty processes called 'cpuwaster'."
rmuser user
"They've been eliminated, thank you for letting us know of problems you have!"
It's called "being a sysadmin". If someone's abusing the machine, delete em.
>
>
> Kevin
>
>
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