Messages in this thread | | | Subject | Re: Interesting analysis of linux kernel threading by IBM | Date | Fri, 21 Jan 2000 10:45:39 +0000 (GMT) | From | Malcolm Beattie <> |
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Larry McVoy writes: > : Or a machine with a lot of users. (For example, a University unix server)
You rang?
> : If it wants to be the most efficient desktop machine, then it doesn't > : need it NOW. However, the average number of programs people are > : running on their machine are increasing, not decreasing. > > This is a completely unsubstatiated statement. OK, everyone, do this: > > $ vmstat > load free cach swap pgin pgou dk0 dk1 dk2 dk3 ipkt opkt int ctx usr sys idl > 0.00 4.3 96.9 0.4 0 0 0 0 0 0 0 0 104 53 0 3 97
As a concrete example of what you saying: on one of our two interactive general-purpose servers we currently have: [~]ermine% uptime 10:33 up 29 days, 15:54, 227 users, load average: 1.61, 1.84, 1.84 % lusers 176 telnetd 9 rlogind 8 xterm 217 tcsh 5 ftpd 448 imapd-4.1.FINAL 11 popper 0 apache 528 distinct users 649 sessions % vmstat Virtual Memory Statistics: (pagesize = 8192) procs memory pages intr cpu r w u act free wire fault cow zero react pin pout in sy cs us sy id 51307 29 97K 1424 28K 2629M 139M 169M 769K 167M 6522 237 6K 946 6 6 88
and on the other we have
% uptime 10:37 up 59 days, 2:08, 286 users, load average: 8.96, 7.34, 7.08 % lusers 263 telnetd 7 rlogind 7 xterm 285 tcsh 3 ftpd 88 imapd-4.1.FINAL 16 popper 0 apache 253 pine 354 distinct users 377 sessions
They're both old (oh, so old) Alphaservers with 1GB RAM: the first has 4 x 250MHz CPUs; the second has 2 x 300MHz CPUs (both running Digital UNIX as it happens, as you can see from the low uptimes compared to our Linux boxes :-).
> Those people with the load field higher than 10, please tell us what you are > doing.
The second machine above does actually tend go over a load average of 10 at peak times (to 20 or 30...) but that's when it's even more riduculously overloaded (~500 concurrent users our of a user population of 12000). As Larry says, even with many hundreds of people hammering on an old machine, the load average stays low when the system is behaving. Now it *is* possible to make the load average go sky high by running silly or buggy programs but we tend to catch and LART the users that run them fairly quickly.
--Malcolm
-- Malcolm Beattie <mbeattie@sable.ox.ac.uk> Unix Systems Programmer Oxford University Computing Services
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