Date: Sun, 02 Jul 2000 07:18:09 -0700 From: Cy Schubert - ITSD Open Systems Group <Cy.Schubert@uumail.gov.bc.ca> To: Alban Hertroys <dalroi@wit401310.student.utwente.nl> Cc: freebsd-stable@FreeBSD.ORG Subject: Re: man nice(1) Message-ID: <200007021418.e62EIww00785@cwsys.cwsent.com> In-Reply-To: Your message of "Sun, 02 Jul 2000 14:09:16 %2B0200." <20000702120917.D5BA71E7E@wit401310.student.utwente.nl>
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In message <20000702120917.D5BA71E7E@wit401310.student.utwente.nl>,
Alban Hertr
oys writes:
> Is it just me or is the man page for nice in error?
>
> It says I have to specify a nice value of (+)20 as "nice -20" and a nice
> value of -20 as "nice --20".
>
> running "nice -20" results in a nice value of -20, though,
> while "nice --20" says:
> nice: Badly formed number.
>
> Eventually it turned out I had to do "nice +20" ...
> The man page of renice does state the nice value parameters correctly,
> which causes a confusing difference between the two commands.
I see you're a csh user. C Shell has a builtin nice which is
incompatible with /usr/bin/nice which is used by the Bourne shell and
any of its descendants.
The csh nice builtin is documented in the csh(1) man page:
nice
nice +number
nice command
nice +number command
The first form sets the scheduling priority for this
shell
to 4. The second form sets the priority to the given
number. The final two forms run command at priority 4 and
number respectively. The greater the number, the less
cpu
the process will get. The super-user may specify
negative
priority by using `nice -number ...'. Command is always
executed in a sub-shell, and the restrictions placed on
commands in simple if statements apply.
If you wish to use the Bourne nice command under csh, you must specify
the full path name.
Why are Bourne and C Shell nice commands not the same? Well the
developers of csh so many years ago chose a different syntax. Should
they be the same? To make them the same would break compatibility with
all other UNIX systems. If you want to make them the same, put the
following in your .cshrc:
alias nice /usr/bin/nice
>
>
> This is with a somewhat older 4.0-STABLE.
> I found this when trying a buildworld "nicely", as my system hottens up
> a tiny bit to much somewhere (probably my pci viper550 with bad fan)
> causing spontaneous reboots after a couple of hours.
I don't see how the nice command would solve this. It just assigns a
different priority to a command and its children causing them to be
selected for execution more or less frequently in relationship to other
processes running on the system. If you have no higher priority work
on the machine, a lower nice value will not make any difference in
execution time or the amount of heat produced by your CPU. Replacing
the bad fan or reducing your CPU's clock rate will help.
Regards, Phone: (250)387-8437
Cy Schubert Fax: (250)387-5766
Team Leader, Sun/DEC Team Internet: Cy.Schubert@osg.gov.bc.ca
Open Systems Group, ITSD, ISTA
Province of BC
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