On Tue, May 23 2006, Martin Devera wrote:Hello,
I see weird output from /sys/block/sd{a,b}/stat on our AMD64-X2 smp machine with HT1000 (Broadcom) SATA with 2 WD 250GB HDDs in MD raid1. AS scheduler was used, change to noop didn't change anything. It is vanilla 2.6.16.1 and here are absolute values in hex and one second differences below:
132CDF 56D62 61753C0 6966BC 165A8EB 5FF5B6C 3B32D6C0 1110594C FFCA89A4 FEE85878 49FF74E4
132CDF 56D62 61753C0 6966BC 165A8EF 5FF5B6C 3B32D6E0 111059D0 FFCA89A1 FEE85C60 79291244
0: 0
1: 0
2: 0
3: 0
4: 4
5: 0
6: 32
7: 132
8: -3
9: 1000
10: 791256416
As you can see in_flight is constantly negative and it is DECREASING slowly all the time.
I can't find any reason for it :-\
Are you using io barriers?
[PATCH] blk: fix gendisk->in_flight accounting during barrier sequence