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

[Kris Kennaway]

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

From: Kris Kennaway <kris at FreeBSD.org>
To: Jakub Jasinski <jakub.jasinski at utoronto.ca>
Cc: freebsd-gnats-submit at FreeBSD.org
Subject: Re: misc/126230: weird process cpu usage stats and weird load average
Date: Tue, 05 Aug 2008 18:48:57 +0200

 Jakub Jasinski wrote:
 > I recompiled the kernel with the ULE scheduler and the only difference
 > now is that every 'working' process has higher WCPU _after_ rsync is
 > activated. Before rsync is activated all process have 0% WCPU.
 > 
 > BTW, thanks for the help.
 > 
 > [root at mail2 ~]# vmstat -i
 > interrupt                          total       rate
 > irq1: atkbd0                          78          0
 > irq4: sio0                          2023          5
 > irq14: ata0                           58          0
 > irq16: uhci0 ehci0                     1          0
 > irq18: ciss0 uhci2                  2618          6
 > irq22: uhci4                          19          0
 > cpu0: timer                       751994       1994
 > irq257: bce1                        2271          6
 > cpu1: timer                       744491       1974
 > cpu2: timer                       744494       1974
 > cpu3: timer                       744513       1974
 > Total                            2992560       7937
 
 Your system is sharing an interrupt between the ciss and one of the USB 
 controllers.  This means that every time there is an interrupt from disk 
 I/O the USB drivers will also wake up to process it.  This could be 
 causing things like moused and cups to run.  What devices are attached 
 to uhci2?
 
 Kris
 
 
 > (snipped top output:)
 > 
 > 60 processes:  1 running, 59 sleeping
 > CPU states:  1.0% user,  0.0% nice, 38.4% system,  2.4% interrupt, 58.1%
 > Mem: 142M Active, 333M Inact, 284M Wired, 52K Cache, 214M Buf, 7154M Fre
 > Swap: 8192M Total, 8192M Free
 > 
 >   PID USERNAME    THR PRI NICE   SIZE    RES STATE  C   TIME   WCPU COMM
 >   662 root          2   4    0 14112K  2504K select 1   0:10 13.43% apcu
 >  1020 root          1  55    0 17196K 12096K select 3   0:08 11.57% rsyn
 >   756 root          1   4    0  9940K  1260K select 2   0:05  7.08% auth
 >   498 root          1   4    0  5808K  1196K select 3   0:05  6.40% mous
 >   471 root          1   4    0  5808K  1196K select 0   0:04  5.86% mous
 >   890 mailnull      1   4    0  9252K  2024K select 0   0:04  5.08% mime
 >   981 root          1   4    0 30108K  5292K select 2   0:04  4.98% send
 >   969 admin         1   4    0 32936K  4608K select 1   0:04  4.88% sshd
 >  1001 admin         1   4    0 32936K  4612K select 1   0:04  4.88% sshd
 >   791 root          1   4    0  9940K  1260K select 3   0:04  4.88% auth
 >   613 root          1   4    0  4684K  1352K select 0   0:04  4.79% sysl
 >   784 root          1   4    0  3604K  1224K select 0   0:04  4.79% cour
 >   792 root          1   4    0  9940K  1260K select 2   0:04  4.79% auth
 >  1018 root          1   4    0 17196K 11808K select 0   0:04  4.69% rsyn
 >   793 root          1   4    0  9940K  1260K select 3   0:04  4.59% auth
 >   719 root          1   4    0 27284K 10392K select 2   0:04  4.59% perl
 >   799 root          1   4    0  3604K  1224K select 2   0:04  4.59% cour
 >   789 root          1   4    0  9940K  1260K select 1   0:04  4.49% auth
 >   790 root          1   4    0  9940K  1260K select 2   0:04  4.49% auth
 >   907 mailnull      2  20    0  4888K  1536K sigwai 1   0:04  4.49% mime
 >   833 root          1   4    0 20960K  3920K select 1   0:04  4.49% sshd
 >   774 root          1   4    0  3604K  1220K select 3   0:04  4.39% cour
 > 
 > On Mon, 4 Aug 2008 17:00:11 GMT
 > Kris Kennaway <kris at freebsd.org> wrote:
 > 
 >> The following reply was made to PR misc/126230; it has been noted by
 >> GNATS.
 >>
 >> From: Kris Kennaway <kris at FreeBSD.org>
 >> To: Jakub Jasinski <jakub.jasinski at utoronto.ca>
 >> Cc: freebsd-gnats-submit at FreeBSD.org
 >> Subject: Re: misc/126230: weird process cpu usage stats and weird
 >> load average Date: Mon, 04 Aug 2008 18:59:15 +0200
 >>
 >>  Jakub Jasinski wrote:
 >>  > No.
 >>  > 
 >>  > I ran ktrace on the processes and ktrace.out was empty.
 >>  > 
 >>  > Read my follow up message: I already had a lengthy conversation
 >>  > with Remko about this.
 >>  > 
 >>  > NONE of the processes were running.  The non-zero TIME is nonsense
 >>  > as well and only accumulated after rsync was left running.
 >>  
 >>  That would be a very strange situation indeed, requiring multiple
 >> things to go wrong in bizarre ways.  The more likely explanation is
 >> that the processes are in fact running and being reported correctly.
 >>  
 >>  Kris
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 > 
 >