Re: [2.6.10-rc1 and prev] System unuseable while writing to disk

["Prakash K. Cheemplavam" <prakashkc@gmx.de>]

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Bill Davidsen wrote:
> Prakash K. Cheemplavam wrote:
> 
>> Hi,
>>
>> I have a problem which doesn't seem to be connected to the i/o 
>> schedulers, because all I tested (cfq, deadline, noop) show the same:
>>
>> While writing (when the kernel actually commits to hd) my system gets 
>> very unresponsive esp when another app I want to use wants to write 
>> (read?) from hd, as well. This is *not* a UDMA problem (at least no 
>> apparent...)! More specific:
>>
>> I wrote this primitive code for writing sequentially:
> 
> 
> May I suggest running "vmstat 1" while this is happening? Looking at the 
> waitio time vs. transfer rates might reveal something. If it all looks 

Here you go. I hope you can see anything. (I attached the file as well...):


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 775044  14520 136460    0    0   935    86 1251   909 13 
5 57 25
  0  0      0 775036  14520 136460    0    0     0     0 1270   536  1 
0 99  0
  0  0      0 775036  14520 136460    0    0     0     0 1225   655  1 
1 98  0
  0  0      0 775036  14520 136460    0    0     0     0 1187   530  1 
0 99  0
  0  0      0 775036  14520 136460    0    0     0     0 1184   517  0 
0 100  0
  0  0      0 775036  14520 136460    0    0     0     0 1188   548  1 
1 98  0
  0  0      0 774876  14532 136460    0    0    12     0 1185   681  2 
1 94  3
  0  0      0 774876  14532 136460    0    0     0     0 1185   479  0 
0 100  0
  0  0      0 774876  14532 136460    0    0     0     0 1180   436  1 
0 99  0
  1  1      0 571740  14732 333736    0    0    32 42628 1325   633  3 
43 52  2
  2  2      0 217812  15072 676648    0    0     0 45184 1523  1771 14 
78  0  8
  1  2      0 220436  15072 676648    0    0     0 49664 1582  1365  9 
6  0 85
  0  2      0  85460  15984 808012    0    0   164 73984 1487  1143 18 
32  0 49
  0  1      0  85716  15984 808140    0    0     0 29056 1493  1381  4 
6  0 90
  0  1      0  86100  15984 808140    0    0     0 40320 1420  1367  3 
2  0 95
  0  1      0  86100  15984 808140    0    0     0 44416 1386   693  0 
2  0 98
  0  1      0  86100  15984 808140    0    0     0 50304 1518  1413  5 
6  0 89
  0  1      0  86164  15984 808140    0    0     0 28544 1452   827  1 
2  0 97
  0  1      0  86292  15984 808140    0    0     0 35840 1386   809  1 
2  0 97
  0  1      0  86356  15984 808140    0    0     0 37376 1450  1373  3 
3  0 94
procs -----------memory---------- ---swap-- -----io---- --system-- 
----cpu----
  r  b   swpd   free   buff  cache   si   so    bi    bo   in    cs us 
sy id wa
  1  1      0  86484  15984 808140    0    0     0 42880 1752  2494  7 
6  0 87
  0  1      0  86484  15984 808140    0    0     0 31872 1608  2098  7 
4  0 89
  0  1      0  86484  15984 808140    0    0     0 45952 1530   795  1 
2  0 97
  0  1      0  86484  15984 808140    0    0     0 44288 1515   814  0 
3  0 97
  0  1      0  90580  15984 808140    0    0     0 29052 1471  1365  5 
5  0 90
  1  0      0  90148  16108 809356    0    0   976  2088 1383  1319 22 
11  0 67
  0  0      0  90148  16108 809360    0    0     4    16 1444   833 10 
5 84  1
  0  0      0  90148  16108 809360    0    0     0     0 1256   473  0 
0 100  0
  0  0      0  90148  16108 809360    0    0     0     0 1379   611  3 
1 96  0
  0  0      0  90148  16108 809360    0    0     0     0 1526  2439 16 
5 79  0
  0  0      0  90148  16164 809360    0    0     0   120 1563  1824 16 
4 80  0


Beginning and end the system is idle and then I start writing down the 
file. During that time thunderbird gets unusable.

> I can't say that I see any such thing with ext[23], so it may be a 
> reiser issue and someone else will have to help. Did you look at the 
> logs to see that there are no useful warnings there?

Nothing in the logs, unfortunately.

Cheers,

Prakash

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