Date: Sun, 25 May 2003 11:01:16 +0800 From: "Paul Hamilton" <paulh@bdug.org.au> To: "Freebsd-Questions" <freebsd-questions@FreeBSD.ORG> Subject: RE: 'top' showing high interrupt rate Message-ID: <AGEHIFHGNEMPFNCPLONMOEKGEKAA.paulh@bdug.org.au> In-Reply-To: <AGEHIFHGNEMPFNCPLONMOEFPEKAA.paul@compwest.com.au>
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Thanks for the reply's. I didn't see them on the list.
Maybe I missed them, so I have pasted them back in here.
--------------------------------------------------------------------
By any chance, have you altered the system quantum (HZ), or enabled
kern.polling?
-Chuck
Run systat and then type ":vmstat" (without quotes) to get the vmstat
screen.
The lower right will have interrupts broken down by device ... this should
help.
-Bill Moran
Try `top -S` instead. This will show system processes as well. Also, use
`systat -v` as previously mentioned to see interrupt counts.
My guess is this box is a gateway/firewall and may be getting pounded on
the network interfaces. Are you running ipfw as well?
- Andy Farkas
--------------------------------------------------------------------
Thanks guys!
I tried: sysctl kern.polling and got:-
sysctl: unknown oid 'kern.polling'
I haven't played around with the system quantum.
I like the systat --> :vmstat and the systat -v command. Very nice!
Here is a dump of what is going on. As you can see, it doesn't show very
much:-
----------------------------------------------------------------------------
--
1 users Load 0.21 0.17 0.20 May 25 10:32
Mem:KB REAL VIRTUAL VN PAGER SWAP PAGER
Tot Share Tot Share Free in out in out
Act 6320 784 13460 944 7616 count
All 24800 1880 2328768 3408 pages
zfod Interrupts
Proc:r p d s w Csw Trp Sys Int Sof Flt cow 241 total
1 7 20 99 241 11 2 7600 wire ata0
irq14
8568 act ata1
irq15
0.2%Sys 59.7%Intr 0.6%User 0.0%Nice 39.5%Idl 5284 inact 4 dc0
irq10
| | | | | | | | | | 3348 cache fdc0
irq6
++++++++++++++++++++++++++++++ 4268 free 9 sio1
irq3
daefr 100 clk
irq0
Namei Name-cache Dir-cache prcfr 128 rtc
irq8
Calls hits % hits % react
3 3 100 pdwake
pdpgs
Disks ad0 ad1 acd0 fd0 md0 intrn
KB/t 0.00 0.00 0.00 0.00 0.00 6480 buf
tps 0 0 0 0 0 3 dirtybuf
MB/s 0.00 0.00 0.00 0.00 0.00 2348 desiredvnodes
% busy 0 0 0 0 0 2374 numvnodes
1160 freevnodes
----------------------------------------------------------------------------
--
Yes, this PC is a gateway to the internet via a modem (see dc0 and sio1
showing activity).
I have tried the ststat -v on 3 or 4 servers, and they all pretty much show
that clk and rtc use 100/128.
However, most of them run at ~15% interupt activity. Hmm, maybe it's 60% on
this server,
because it's only a Pentium 166.
Anyone else have an insight on this?
Hmm, I then tried killing natd, and lo-and-behold, interrupts fell to 0.5%!!
Restarted natd and interrupts are still < 0.5%! Here is the natd via top
before and after:-
108 root 2 0 464K 152K select 96:45 0.00% 0.00% natd
15462 root 2 0 420K 272K select 0:00 0.00% 0.00% natd
The only difference is the size and res. Anyone know of problems with natd?
The server was acting ok, just reporting that the interrupt usage was
running at 60%.
I will keep an eye on this over the next few days.
Cheers,
Paul Hamilton
-----Original Message-----
From: owner-freebsd-questions@freebsd.org
[mailto:owner-freebsd-questions@freebsd.org]On Behalf Of Paul Hamilton
Sent: Wednesday, 21 May 2003 10:38 PM
To: Freebsd-Questions
Subject: 'top' showing high interrupt rate
Hi,
I noticed that top shows a rather high interrupt rate, usually hovering
around 60%! Here is a sample:-
last pid: 2879; load averages: 0.34, 0.24, 0.18
up 1+17:26:56 17:18:10
36 processes: 2 running, 33 sleeping, 1 zombie
CPU states: 0.6% user, 0.0% nice, 0.0% system, 59.8% interrupt, 39.6%
idle
Mem: 11M Active, 5072K Inact, 7988K Wired, 3552K Cache, 6480K Buf, 960K Free
Swap: 128M Total, 4608K Used, 123M Free, 3% Inuse
PID USERNAME PRI NICE SIZE RES STATE TIME WCPU CPU
COMMAND
135 root 10 0 980K 528K nanslp 11:38 0.00% 0.00% cron
201 root 2 0 2824K 1132K select 3:46 0.00% 0.00% ppp
108 root 2 0 452K 208K select 0:29 0.00% 0.00% natd
127 root 2 0 2760K 1704K select 0:14 0.00% 0.00% named
223 root 2 0 2068K 908K select 0:10 0.00% 0.00% sshd
212 root 2 0 2044K 876K select 0:10 0.00% 0.00% sshd
<snip>
pstat -T says:
120/1064 files
4M/127M swap space
vmstat 10 says:
procs memory page disks faults cpu
r b w avm fre flt re pi po fr sr ad0 ad1 in sy cs us sy
id
0 0 0 12992 4992 1 0 0 0 1 0 0 0 237 52 8 0 59
41
0 0 0 9404 4992 1 0 0 0 0 0 0 0 229 35 6 0 60
40
0 0 0 15572 4868 16 0 0 0 7 0 0 0 231 938 10 1 61
38
0 0 0 17820 4868 8 0 0 0 0 0 1 0 230 45 8 0 60
40
0 0 0 12492 5224 8 0 0 0 9 0 0 0 231 47 8 1 60
39
dmesg says:
Copyright (c) 1992-2000 The FreeBSD Project.
Copyright (c) 1979, 1980, 1983, 1986, 1988, 1989, 1991, 1992, 1993, 1994
The Regents of the University of California. All rights reserved.
FreeBSD 4.2-RELEASE #1: Tue Feb 13 22:51:23 WST 2001
root@ant.compwest.net.au:/usr/src/sys/compile/ANT
Timecounter "i8254" frequency 1193182 Hz
CPU: Pentium/P55C (165.79-MHz 586-class CPU)
Origin = "GenuineIntel" Id = 0x544 Stepping = 4
Features=0x8001bf<FPU,VME,DE,PSE,TSC,MSR,MCE,CX8,MMX>
real memory = 33554432 (32768K bytes)
avail memory = 29478912 (28788K bytes)
Yes, the server only has 32MB or RAM, however, it's only using 4MB of VM.
Anyone have any idea how to troubleshoot further? How can I isolate what is
causing the rather high interrupt rate?
Cheers,
Paul Hamilton
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