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Re: too much context switching



On 04/07/11 19:04, Camaleón wrote:
On Mon, 04 Jul 2011 11:20:18 -0600, ChadDavis wrote:

(...)

When I execute the command:

vmstat 5 5

I get:


procs -----------memory---------- ---swap-- -----io-----system-- ----cpu----
r  b   swpd   free   buff  cache   si   so    bi    bo   in   cs us sy  id wa
2  0      0 5741808 573028 1040628    0    0   122    42   53 1107  4  1 92  4
1  0      0 5747552 573036 1034488    0    0     0    22   14 2522  1  0 99  0
0  0      0 5747460 573060 1034488    0    0     0    32   18 2493  1  0 99  0
0  0      0  5747740 573096 1034488   0    0     0    57   72 4142  1  1 98  0
0  0      0 5747616 573144  1034468   0    0     0    61   20  687  1  0 99  0


Aren't those context switch number pretty high?  I realize this may be
all relative, but these numbers are WAY higher than I see in the
reference materials, so . . .

You mean the "cs" column?

sm01@stt008:~$ vmstat 5 5
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 6261340  66836 1082052    0    0     9    37   38  176  1  0 98  0
  0  0      0 6261312  66836 1082052    0    0     0    14   73  119  0  0 100  0
  0  0      0 6261416  66836 1082052    0    0     0    58   75  108  0  0 100  0
  0  0      0 6261568  66836 1082052    0    0     0    25  111  180  0  0 100  0
  0  0      0 6261600  66836 1082052    0    0     0     0  101  169  0  0 100  0

Just to compare, I dunno what that means, neither if lower values are
better or worse nor why. Let's see what people has to say on this regard :-)

I get very differing figures for different machines. It seems to relate to CPU speed.

P4M 1600MHz
procs -----------memory---------- ---swap-- -----io---- -system-- ----cpu----
 r  b   swpd   free   buff  cache   si   so    bi    bo   in   cs us sy id wa
 1  0   1716 270036 100064 391256    0    0   160    70  184  305 14  4 79  3
 0  0   1716 269688 100064 391256    0    0     0     0  283  601 61  8 31  0
 0  0   1716 269736 100064 391256    0    0     0     0  146  203  5  1 93  0
 0  0   1716 269768 100064 391256    0    0     0     0  174  135 32  3 65  0
 0  1   1716 259792 100212 397784    0    0  1332     0  325  737 35  5 30 30

Celeron M 500MHz
procs -----------memory---------- ---swap-- -----io---- -system-- ----cpu----
 r  b   swpd   free   buff  cache   si   so    bi    bo   in   cs us sy id wa
 0  0   1356   6140 137712 138576    0    0    24    18   35   13  1  2 95  1
 1  0   1356   6900 137716 138576    0    0     0    27   76   37  6  1 93  0
 0  0   1356   6908 137716 138580    0    0     0     0   65   29  0  0 99  0
 0  0   1356   6916 137720 138580    0    0     0    26   63   33  0  0 100  0
 0  0   1356   6916 137728 138584    0    0     0    41   76   34  0  0 99  0

K7 XP3200+
procs -----------memory---------- ---swap-- -----io---- -system-- ----cpu----
 r  b   swpd   free   buff  cache   si   so    bi    bo   in   cs us sy id wa
 0  0  34288 224640  53568 980396    0    1   222   758  239  372 13  5 81  1
 1  0  34288 222540  53620 982368    0    0     0   471 1157 1922  3  3 93  1
 1  0  34288 220308  53660 984576    0    0     0   454 1137 1941  3  2 94  1
 0  0  34288 218200  53712 986568    0    0     0   453 1143 1906  3  3 94  0
 2  0  34288 216092  53752 988736    0    0     0   489 1138 1936  3  2 94  1
(This was when the system wasn't very busy. When busy, the cs figures were around 4000)

P1 MMX 166MHz
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   1064   2820  15048    0    0   210     9  119  220 20 24 32 24
 0  0      0   1068   2824  15048    0    0     0     3   45   21  0  0 99  0
 0  0      0   1084   2824  15048    0    0     0     0   43   16  0  0 100  0
 0  0      0   1104   2824  15048    0    0     0     0   42   15  0  0 100  0
 0  0      0   1088   2824  15048    0    0     0     0   43   18  0  0 100  0

I don't know if any of this helps.

Dom


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