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Date:      Sat, 6 Aug 2011 20:47:36 -0300
From:      Mario Lobo <lobo@bsd.com.br>
To:        freebsd-questions@freebsd.org
Subject:   High interrupt rate
Message-ID:  <201108062047.36472.lobo@bsd.com.br>

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Hi there;

My system is a FreeBSD 8.2-STABLE #0: Wed Jul 13 17:32:44 BRT 2011 i386

I have 4 nics. sis0, rl0, vr0 and dc0. The last three are in polling mode 
(which I did to see if it would decrease the int amount).

The int rate for sis0 is low.

vmstat -i reports:

interrupt                          total       rate
irq6: fdc0                             1          0
irq14: ata0                       163039          6
irq15: ata1                           29          0
irq19: sis0 vr0                   688525         29
irq20: ohci0                          27          0
irq23: ehci0                           2          0
cpu0: timer                     46922025       2000
cpu1: timer                     46918117       1999
Total                           94691765       4036


But top reports:

last pid:  5163;  load averages:  0.04,  0.09,  0.08                                                                                                                                           
up 0+06:30:13  20:13:59
144 processes: 3 running, 121 sleeping, 20 waiting
CPU:  0.0% user,  0.0% nice,  1.2% system, 24.0% interrupt, 74.8% idle
Mem: 42M Active, 154M Inact, 116M Wired, 96K Cache, 112M Buf, 1667M Free
Swap: 4000M Total, 4000M Free

  PID USERNAME    THR PRI NICE   SIZE    RES STATE   C   TIME   WCPU COMMAND
   11 root          2 171 ki31     0K    16K CPU0    0 706:33 103.37% idle
   12 root         20 -32    -     0K   160K WAIT    1  67:16 97.46% intr
    0 root         10 -68    0     0K    72K -       1   1:34  2.98% kernel

Systat reports:

    1 users    Load  0.12  0.11  0.08                  Aug  6 20:15

Mem:KB    REAL            VIRTUAL                       VN PAGER   SWAP PAGER
        Tot   Share      Tot    Share    Free           in   out     in   out
Act   56096    5076   194524     9784 1706152  count
All  113900    6624  2341492    13732          pages
Proc:                                                            Interrupts
  r   p   d   s   w   Csw  Trp  Sys  Int  Sof  Flt        cow    4042 total
             73      6150   10  405   44  30k             zfod        fdc0 
irq6
                                                          ozfod       ata0 
irq14
 1.5%Sys  25.0%Intr  0.0%User  0.0%Nice 73.5%Idle        %ozfod       ata1 
irq15
|    |    |    |    |    |    |    |    |    |    |       daefr    44 sis0 vr0 
1
=++++++++++++                                             prcfr       ohci0 20
                                         5 dtbuf          totfr       ehci0 23
Namei     Name-cache   Dir-cache    600000 desvn          react  1999 cpu0: 
time
   Calls    hits   %    hits   %     27121 numvn          pdwak  1999 cpu1: 
time
                                       943 frevn          pdpgs
                                                          intrn
Disks   ad0   ad1   cd0 pass0                      118476 wire
KB/t   0.00  0.00  0.00  0.00                       43796 act
tps       0     0     0     0                      157764 inact
MB/s   0.00  0.00  0.00  0.00                          96 cache
%busy     0     0     0     0                     1706056 free
                                                   114880 buf 


I know 75% idle is not bad but this machine, when not under load on a saturday 
night like today, used to be at around 98% idle 99% of the time. Now its is at 
72% idle 99.9% of the time. It has been like this all day.

The only things with a high interrupt rate are

cpu0: timer                     46922025       2000
cpu1: timer                     46918117       1999

What could be causing this?

thanks,
-- 
Mario Lobo
http://www.mallavoodoo.com.br
FreeBSD since 2.2.8 [not Pro-Audio.... YET!!] (99% winblows FREE)



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