Re: [RFC][PATCH] iowait statistics

William Lee Irwin III (wli@holomorphy.com)
Wed, 15 May 2002 11:46:46 -0700


On Wed, May 15, 2002 at 03:33:58PM -0300, Rik van Riel wrote:
> Well, with the amount of memory you have in the machine
> I expect the time spent in idle and iowait to be fairly
> limited during a repetitive kernel compile ;)
> If everything "looks" normal in top and vmstat things
> should be ok.

On Wed, May 15, 2002 at 03:33:58PM -0300, Rik van Riel wrote:
$ vmstat 1
procs memory swap io system cpu
r b w swpd free buff cache si so bi bo in cs us sy id
17 0 0 0 182880 32364 55180 0 0 2 77 29 229 84 6 10
17 0 0 0 178840 32380 55268 0 0 0 1240 169 766 95 5 0
16 0 0 0 168056 32380 55480 0 0 0 0 104 829 95 5 0
20 0 0 0 197960 32380 55616 0 0 0 0 105 1156 94 6 0
16 0 0 0 179416 32380 55632 0 0 0 0 108 994 95 5 0
18 0 0 0 184428 32380 55692 0 0 0 0 109 954 94 6 0
16 0 0 0 165684 32396 55720 0 0 0 1148 182 1069 96 4 0
17 0 0 0 155572 32396 55732 0 0 0 0 104 854 96 4 0
17 0 0 0 181108 32400 56636 0 0 0 0 104 853 95 5 0
18 0 0 0 194772 32400 56692 0 0 0 0 103 955 94 6 0
16 0 0 0 185068 32400 56856 0 0 0 0 104 1006 95 5 0
18 1 0 0 191744 32408 56972 0 0 0 1808 286 1062 95 5 0
16 0 0 0 202512 32408 57092 0 0 0 0 103 956 94 6 0
17 0 0 0 191116 32408 57140 0 0 0 0 103 1143 91 9 0
17 0 0 0 202032 32408 57288 0 0 0 0 103 899 93 7 0
17 0 0 0 187764 32408 57320 0 0 0 0 103 928 92 8 0
18 1 0 0 198048 32408 57400 0 0 0 1776 294 1026 94 6 0
16 1 0 0 205108 32408 57436 0 0 0 0 104 842 96 4 0
16 0 0 0 181964 32408 57488 0 0 0 0 103 1028 95 5 0
16 0 0 0 175224 32408 57524 0 0 0 0 104 961 95 5 0

All good there. OTOH:

$ top
fscanf failed on /proc/stat for cpu 1
fscanf failed on /proc/stat for cpu 2
fscanf failed on /proc/stat for cpu 3

... and it proceeds thus:

11:45am up 2:00, 4 users, load average: 17.18, 16.86, 16.94
52 processes: 50 sleeping, 2 running, 0 zombie, 0 stopped
CPU0 states: 72.2% user, 27.1% system, 0.0% nice, 0.2% idle
fscanf failed on /proc/stat for cpu 1
Mem: 499088K av, 174936K used, 324152K free, 0K shrd, 32684K buff
Swap: 1052248K av, 0K used, 1052248K free 61812K cached

PID USER PRI NI SIZE RSS SHARE STAT %CPU %MEM TIME COMMAND
26200 wli 25 0 13780 13M 2204 R 10.0 2.7 0:01 cc1
26246 wli 15 0 1060 1060 804 R 0.1 0.2 0:00 top
1 root 15 0 492 492 428 S 0.0 0.0 0:00 init
2 root 0K 0 0 0 0 SW 0.0 0.0 0:00 migration_CPU0
3 root 0K 0 0 0 0 SW 0.0 0.0 0:00 migration_CPU1
4 root 0K 0 0 0 0 SW 0.0 0.0 0:00 migration_CPU2
5 root 0K 0 0 0 0 SW 0.0 0.0 0:00 migration_CPU3
6 root 15 0 0 0 0 SW 0.0 0.0 0:00 keventd
7 root 34 19 0 0 0 SWN 0.0 0.0 0:00 ksoftirqd_CPU0
8 root 34 19 0 0 0 SWN 0.0 0.0 0:00 ksoftirqd_CPU1
9 root 34 19 0 0 0 SWN 0.0 0.0 0:00 ksoftirqd_CPU2
10 root 34 19 0 0 0 SWN 0.0 0.0 0:00 ksoftirqd_CPU3
11 root 25 0 0 0 0 SW 0.0 0.0 0:00 kswapd
12 root 25 0 0 0 0 SW 0.0 0.0 0:00 pdflush

... i.e. a little bit of recurring fscanf stuff.

Cheers,
Bill
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