*BSD News Article 71178


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From: mandrews@bob.Wittenberg.EDU (Mike Andrews)
Newsgroups: comp.unix.bsd.freebsd.misc
Subject: iijppp using 100% CPU even when modem idle?
Date: 17 Jun 96 01:51:34 GMT
Organization: Wittenberg University, Springfield OH
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Message-ID: <mandrews.834976294@bob.wittenberg.edu>
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This one's been driving me nuts for a long time, but as I'm functional
regardless I've been too lazy to ask about it until now...

How normal is it for iijppp to take up 100% of the CPU, even when the
link is totally idle, and thus the kernel is seeing no comm interrupts?
top indicates it is taking about 80% kernel mode and 20% user mode time.

I'm using iijppp under FreeBSD 2.1.0-RELEASE to route a subnet at my house
over to the network at work.  I was using a 386sx-25 with a Hayes ESP serial
board, until the ancient 80 meg IDE head crashed, and now am using a 486dx2/66
with a plain 16550 serial board...  in either case, at 115200 bps, driving a
28.8K external modem.

Yet someone I know (hi James) has *multiple* 115.2K connections on a 386/40
with FreeBSD and none of the ppp processes use much CPU at all.  Our iijppp
config files are about as identical as they can get considering the
differences in our setups.  What could I have done wrong?  I thought the
whole point of iijppp was to use less kernel time than pppd... :)

Top output (on 486/66 -- it was 116% (!?) on the 386sx):

load averages:   1.09,  1.05,  1.01                                    22:12:22
38 processes:  2 running, 36 sleeping
Cpu states: 28.6% user,  0.0% nice, 69.9% system,  1.5% interrupt,  0.0% idle
Memory: 7980K Active, 728K Inact, 2532K Wired, 2528K Cache, 536K Free
Swap:   66M Total, 57M Free, 13% Inuse

  PID USERNAME PRI NICE   SIZE   RES STATE   TIME   WCPU    CPU COMMAND
 2626 root     105    0   468K  204K run   313.0H 97.31% 97.31% ppp

I'll post my routing table and both kernel config files if it'll help,
but I'll save the bandwidth for now.
-- 
-- Mike Andrews  -  mandrews@wittenberg.edu  -  mandrews@termfrost.org (NeXT)
-- Programmer/Analyst, webmaster/netnews guy, Wittenberg Univ, Springfield OH
-- http://www.termfrost.org/~mandrews/           "Don't get even, get odd..."