Hello,
I am using fio to generate a simple sequential workload with request
size of 128K with following job file but I can observe the generated
IO request size is 4K, I was wondering who is responsible in block
layer to shrink the fio requests granularity from 128K to 4K ? :
1 ; -- start job file --
2 [global]
3 rw=write
4 size=128M
5
6 [job1]
7 ioengine=libaio
8 iodepth=512
9 bs=128k
10 direct=1
11 numjobs=1
12 filename=/dev/sde
13 ; -- end job file --
The blktrace shows that the request sizes are all 4KB (8 sector), here
is a peace of output trace that collected while fio is running.
21 8,64 5 21 0.000031322 29848 I W 32 + 8 [fio]
22 8,64 5 22 0.000031868 29848 Q WS 40 + 8 [fio]
23 8,64 5 23 0.000032181 29848 G WS 40 + 8 [fio]
24 8,64 5 24 0.000032352 29848 I W 40 + 8 [fio]
25 8,64 5 25 0.000032826 29848 Q WS 48 + 8 [fio]
26 8,64 5 26 0.000033145 29848 G WS 48 + 8 [fio]
27 8,64 5 27 0.000033310 29848 I W 48 + 8 [fio]
28 8,64 5 28 0.000033781 29848 Q WS 56 + 8 [fio]
29 8,64 5 29 0.000034045 29848 G WS 56 + 8 [fio]
30 8,64 5 30 0.000034227 29848 I W 56 + 8 [fio]
31 8,64 5 31 0.000034498 29848 D W 32 + 8 [fio]
32 8,64 5 32 0.000036314 29848 D W 40 + 8 [fio]
33 8,64 5 33 0.000038032 29848 D W 48 + 8 [fio]
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