Date: Sun, 13 May 2001 00:38:13 +0200 From: Erik Trulsson <ertr1013@student.uu.se> To: Nuno Teixeira <nuno.teixeira@pt-quorum.com> Cc: freebsd-stable@freebsd.org Subject: Re: load averages - the meaning Message-ID: <20010513003813.A11072@student.uu.se> In-Reply-To: <20010512230357.Y1738-100000@gateway.bogus>; from nuno.mailinglists@pt-quorum.com on Sat, May 12, 2001 at 11:12:30PM %2B0100 References: <20010512230357.Y1738-100000@gateway.bogus>
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On Sat, May 12, 2001 at 11:12:30PM +0100, Nuno Teixeira wrote: > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > Hello to all, > > I don't know if this is the right list to make my question. If it doesn't > please forgive me. > > Well, the question is related to "load averages" that we see in "w", "top" > and other system utilities. I have look at this programs man pages but I > don't find the really meaning of it. > > In this momment I am doing a "make -j4 buildworld" in a X11 envirement > (XFree86 / IceWM) on my Cyrix 200 and the load averages are about 4.88. > > What the limits of load averages and what the danger values and in what > that this values are based. > > Thanks very much, > The "load" is the number of processes that want to run at any given time. Thus a load average of 0.0 means that no processes wanted to run while a load average of 3.2 means that on average 3.2 processes wanted to run. Thus the minimum is 0 and there is no max. Anything below 1.0 is good. (Since that means that all processes got all the CPU-time they wanted.) A load above, say, 3.0 over a long time means that you probably need a faster machine. (If you have multiple CPUs you can multiply all the numbers above with the number of CPUs.) No danger values but if the load becomes high the machine will probably start to feel sluggish. Basically the load average is a *rough* guide to how busy a machine is. Note that if you have a CPU-intensive program running in the background with a high nice-level it will not affect the perceived performance of the mahine much although it will increade the load by ~1.0 OTOH a I/O-intensive program will not contribute much to the load-average but can cause a noticable drop in the perceived performance. A load of 4.88 when doing a make -j4 is about what I would expect. Note that for 'make -jN' it is probably not useful to specify a value of N larger than 2 (or maybe 3) times the number of CPUs installed in your computer. -- <Insert your favourite quote here.> Erik Trulsson ertr1013@student.uu.se To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message
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