lkml.org 
[lkml]   [2003]   [Nov]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: I/O issues, iowait problems, 2.4 v 2.6
Paul Venezia <pvenezia@jpj.net> wrote:
>
> vmstat output
>
>
> procs memory swap io system cpu
> r b swpd free buff cache si so bi bo in cs us sy id wa
> 0 0 0 1427316 8572 68472 0 0 0 0 1012 17 0 0 100 0
> 0 0 0 1427348 8580 68464 0 0 0 50 1014 20 0 0 99 1
> 0 0 0 1427412 8580 68464 0 0 0 0 1012 23 0 0 100 0
> 0 0 0 1427420 8580 68464 0 0 0 0 1012 15 0 0 100 0
> 0 0 0 1427484 8588 68456 0 0 0 8 1013 20 0 0 100 0
> 0 0 0 1427484 8588 68456 0 0 0 0 1012 22 0 0 100 0
> 0 0 0 1427484 8588 68456 0 0 0 0 1012 15 0 0 100 0
> 0 10 0 1318012 9776 169132 0 0 392 11202 34735 40869 4 33 32 32
> 2 6 0 1249532 10820 233980 0 0 0 1422 34765 42133 8 34 8 49
> 2 4 0 1192188 12048 288104 0 0 10 5276 33213 38553 11 39 15 36
> 4 4 0 1166588 12584 311844 0 0 4 0 31907 37992 14 41 18 26
> 0 4 0 1157372 13088 319976 0 0 4 1978 30261 35581 15 41 17 27
> 2 4 0 1163068 13460 313824 0 0 0 1886 29806 35017 16 41 15 28
> 4 4 0 1155700 13948 320544 0 0 0 202 30341 35867 15 42 16 27
> 3 4 0 1157044 14372 318692 0 0 0 696 30072 35217 16 43 17 24
> 4 4 0 1136820 15028 337688 0 0 0 1574 31872 36292 17 47 13 23
> 4 2 0 1141428 15404 332552 0 0 0 1980 30494 34756 17 46 17 20
> 4 2 0 1136052 15936 337256 0 0 2 2166 30653 35264 18 47 13 23
> 0 10 0 1136948 16284 336092 0 0 0 3456 26323 31729 10 30 25 35
> 0 14 0 1135668 16336 337264 0 0 0 2446 6548 7126 1 5 45 48
> 0 13 0 1135668 16336 337264 0 0 0 110 1038 59 0 0 54 46
> 0 13 0 1135676 16336 337264 0 0 0 0 1030 22 0 0 75 25
> 0 15 0 1133500 16404 336788 0 0 0 9304 6265 5409 2 6 37 55
> 0 13 0 1133308 16912 332132 0 0 0 11572 56145 61147 1 6 2 90
> 2 13 0 1131452 17088 333860 0 0 0 1316 18934 21857 2 11 18 69
> 0 13 0 1128444 17304 336772 0 0 0 1128 20925 23989 3 12 19 66
> 0 13 0 1129340 17548 335440 0 0 0 964 21529 25782 3 14 10 72
> 0 13 0 1128636 17776 336096 0 0 0 338 20924 23571 4 15 1 81
> 0 12 0 1135548 17980 313112 0 0 0 4056 21764 27560 3 15 15 66
> 0 12 0 1135868 18204 312616 0 0 0 4434 21152 25559 3 13 24 60
> 0 11 0 1146316 18352 287172 0 0 0 3442 18240 19442 2 10 40 47
> 2 11 0 1143052 18564 290428 0 0 0 1812 20483 22976 3 14 12 71
> 0 11 0 1142668 18720 290680 0 0 32 3298 15806 17710 3 10 17 70
> 0 10 0 1146444 18940 286856 0 0 0 2106 21450 25860 4 14 37 45

OK, the IO rates are obviously very poor, and the context switch rate is
suspicious as well. Certainly, testing with the single disk would help.


But. If the workload here was a simple dd of /dev/zero onto a regular
file then why on earth is the pagecache size not rising? Could you please
do:

rm foo
cat /dev/zero > foo
and rerun the `vmstat 1' trace? Make sure that after the big initial jump,
the `cache' column is increasing at a rate equal to the I/O rate. Thanks.


-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-03-22 13:58    [from the cache]
©2003-2011 Jasper Spaans