Subject: Re: netbsd machines get slow and hang, nfs suspected
To: Eric Volpe <epv@panix.com>
From: Bill Sommerfeld <sommerfeld@orchard.medford.ma.us>
List: current-users
Date: 03/22/1996 22:48:44
[10,000 context switches in one second??? And note that all of a sudden,
for a short time, over 100 httpds become runnable. Whatever that means-
they don't seem to do anything. We see this happen several more times.]
 2 238 0 45216   124  200 104 119  32   0 256 78  495  106 10263  1 19  80
 0 230 0 44808   124  169  52  77   4   0 122 78  394  191 6004  0 25  74
 112 150 0 45092   244   62 171  52  66   0 327 80  338   92 8913  0 27  73

It would be worthwhile to figure out which wait channel they were all
piled up on; you can get this from `ps'.  You may want to get both the
`wchan' (the symbolic name) and the `nwchan' (the actual address
waited on)

Most likely all hundred were piled up on the same wait channel, and
then something woke it up, causing a thundering herd of processes to
run in circles trying to grab whatever it was they were waiting for...

						- Bill