misc/126230: weird process cpu usage stats and weird load

[Jakub Jasinski]

The following reply was made to PR misc/126230; it has been noted by GNATS.

From: Jakub Jasinski <jakub.jasinski at utoronto.ca>
To: Gavin Atkinson <gavin at freebsd.org>
Cc: freebsd-gnats-submit at FreeBSD.org
Subject: Re: misc/126230: weird process cpu usage stats and weird load
Date: Thu, 7 Aug 2008 22:21:42 -0400

 I killed most daemons to make the problem more obvious:
 
 It seems rather peculiar how a.out (which is select()-ing; see the code
 in my previous post or the other bug report) is using 7.23% cpu.
 
 last pid: 17533;  load averages:  0.00,  0.00,  0.00          up 2
 +02:41:29  22:00:50 32 processes:  1 running, 31 sleeping
 CPU states:  0.0% user,  0.0% nice,  0.1% system,  0.0% interrupt,
 99.9% idle last pid: 17536;  load averages:  0.99,  0.24,
 0.08          up 2+02:43:02  22:02:23 34 processes:  6 running, 28
 sleeping CPU states:  0.7% user,  0.0% nice, 19.3% system,  2.6%
 interrupt, 77.4% idle Mem: 29M Active, 723M Inact, 374M Wired, 88K
 Cache, 214M Buf, 6787M Free Swap: 8192M Total, 8192M Free
 
   PID USERNAME    THR PRI NICE   SIZE    RES STATE  C   TIME   WCPU
 COMMAND
 17536 root 1   4    0 18220K 12548K RUN    3   0:07 11.10% rsync
 17532 root 1   4    0  2532K   660K select  3 0:05  7.23% a.out
 832 root 1   4    0 20960K  4000K select 2 0:14  7.23% sshd
 17300 admin 1   4    0 32936K  4624K select 2   0:06  6.79% sshd
 17535 root 1  96    0  7656K  2152K CPU1   1   0:05  6.67% top
 612 root 1   4    0  4684K  1352K CPU0   0   0:14  6.64% syslogd
 17534 root 1   4    0 17196K 12256K RUN    2   0:05  6.62% rsync
 545 root 1   4    0 1616K   628K select 0   0:14  6.25% devd
 1004 admin 1   4    0 32936K  4624K CPU2   0   0:14  6.05% sshd
 17261 admin 1   4 0 32936K  4632K CPU3   3   0:06  5.66% sshd
 848 root 1   8 0  5736K  1396K nanslp 2   0:00  0.00% cron
 17304 root 1 20    0  9616K  2824K pause  0   0:00  0.00% csh
 913 smmsp 1 20    0 11720K  3972K pause  0   0:00  0.00% sendmail
 1022 root 1   5    0  8692K  2760K ttyin  2   0:00  0.00% bash
 17256 root 1   4    0 32936K  4568K sbwait 1   0:00  0.00% sshd
 17297 root 1   4    0 32936K  4560K sbwait 1   0:00 0.00% sshd
 988 root 1   4    0 32936K  4560K sbwait 1   0:00 0.00% sshd
 17274 root 1   8    0  8692K  2768K wait  3 0:00  0.00% bash
 17269 root 1  20    0  9616K  2788K pause 0   0:00  0.00% csh
 1018 root 1  20    0  9616K  2748K pause 0   0:00  0.00% csh
 1006 admin 1   8    0  8692K  2740K wait 2   0:00  0.00% bash
 17263 admin 1   8    0  8692K  2752K wait   3   0:00  0.00% bash
 17303 admin 1   8    0 19400K 1808K wait 3   0:00  0.00% su
 17268 admin 1   8    0 19400K 1808K wait   2   0:00 0.00% su
 17302 admin 1   8    0  8692K 2752K wait   3   0:00  0.00% bash
 1017 admin 1   8    0 19400K 1808K wait   3   0:00  0.00% su
 953 root 1   5    0  4668K 1200K ttyin  1   0:00  0.00% getty
 954 root 1   5    0  4668K 1200K ttyin  1   0:00  0.00% getty
 955 root 1   5    0  4668K 1200K ttyin  2   0:00  0.00% getty
 
 Now, get cracking and fix select(). ;)
 
 On Thu, 7 Aug 2008 20:40:06 GMT
 Gavin Atkinson <gavin at freebsd.org> wrote:
 
 > The following reply was made to PR misc/126230; it has been noted by
 > GNATS.
 > 
 > From: Gavin Atkinson <gavin at FreeBSD.org>
 > To: bug-followup at FreeBSD.org
 > Cc:  
 > Subject: Re: misc/126230: weird process cpu usage stats and weird load
 > Date: Thu, 7 Aug 2008 21:35:17 +0100 (BST)
 > 
 >  Just a thought: what is the output of "sysctl dev.cpu.0" both
 > before, and after running rsync?  If for some reason your CPU is
 > ending up in a very low frequency mode, then it's not inconceivable
 > that daemons would appear to take a much greater share of the CPU
 > than usual.  Also, I'm assuming the clock maintains time normally?
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