statistics infrastructure

[Fengguang Wu <fengguang.wu@gmail.com>]

On Sun, Jun 04, 2006 at 01:50:11PM -0700, Andrew Morton wrote:
> statistics-infrastructure.patch
 
>  Another tough one.  It offers generic intrastructure for non-task-related
>  instrumentation and it would really be good if someone who has an interest
>  in this for something other than the zfcp driver could stand up and say
>  "this works for us".

I'm having a try of it. Looks good for my case, except some fixable
issues/bugs. Here is a sample session for querying the readahead statistics:

root ~# echo state=on > /debug/statistics/readahead/definition
root ~# cat /debug/statistics/readahead/definition
name=io_block state=on units=/ type=counter_inc data=[  108.272356] started=[  218.797000] stopped=[  201.533118]
name=read_random state=on units=pages/requests type=utilisation data=[  108.272459] started=[  218.797004] stopped=[  201.533146]
name=readahead-fadvise state=on units=pages/requests type=utilisation data=[  108.272472] started=[  218.797005] stopped=[  201.533149]
name=readahead-stock state=on units=pages/requests type=utilisation data=[  108.272476] started=[  218.797005] stopped=[  201.533152]
name=readaround-mmap state=on units=pages/requests type=utilisation data=[  108.272479] started=[  218.797006] stopped=[  201.533155]
name=readahead-mmap state=on units=pages/requests type=utilisation data=[  108.272482] started=[  218.797006] stopped=[  201.533158]
name=readahead-initial state=on units=pages/requests type=utilisation data=[  108.272485] started=[  218.797007] stopped=[  201.533161]
name=readahead-state state=on units=pages/requests type=utilisation data=[  108.272488] started=[  218.797007] stopped=[  201.533164]
name=readahead-context state=on units=pages/requests type=utilisation data=[  108.272491] started=[  218.797008] stopped=[  201.533166]
name=readahead-contexta state=on units=pages/requests type=utilisation data=[  108.272494] started=[  218.797008] stopped=[  201.533169]
name=readahead-backward state=on units=pages/requests type=utilisation data=[  108.272497] started=[  218.797009] stopped=[  201.533172]
name=readahead-onthrash state=on units=pages/requests type=utilisation data=[  108.272500] started=[  218.797009] stopped=[  201.533175]
name=readahead-onseek state=on units=pages/requests type=utilisation data=[  108.272503] started=[  218.797010] stopped=[  201.533178]
name=rescue state=on units=pages/chunks type=utilisation data=[  108.272506] started=[  218.797011] stopped=[  201.533181]
name=size_drop state=on units=from-pages/delta-pages type=counter_inc data=[  108.272509] started=[  218.797011] stopped=[  201.533184]
root ~# cat /debug/statistics/readahead/data
io_block 40
read_random 0 0 0.000 0
readahead-fadvise 0 0 0.000 0
readahead-stock 0 0 0.000 0
readaround-mmap 7 1 28.286 88
readahead-mmap 0 0 0.000 0
readahead-initial 2 5 5.000 5
readahead-state 1331 256 256.010 269
readahead-context 0 0 0.000 0
readahead-contexta 0 0 0.000 0
readahead-backward 0 0 0.000 0
readahead-onthrash 0 0 0.000 0
readahead-onseek 0 0 0.000 0
rescue 0 0 0.000 0
size_drop 13
root ~#
root ~# echo  name=readahead-initial type=histogram_lin entries=32 range_min=8 base_interval=8 > /debug/statistics/readahead/definition
root ~# cat /debug/statistics/readahead/data
io_block 53
read_random 0 0 0.000 0
readahead-fadvise 0 0 0.000 0
readahead-stock 0 0 0.000 0
readaround-mmap 7 1 28.286 88
readahead-mmap 0 0 0.000 0
readahead-initial <=8 0
readahead-initial <=16 0
readahead-initial <=24 0
readahead-initial <=32 0
readahead-initial <=40 0
readahead-initial <=48 0
readahead-initial <=56 0
readahead-initial <=64 0
readahead-initial <=72 0
readahead-initial <=80 0
readahead-initial <=88 0
readahead-initial <=96 0
readahead-initial <=104 0
readahead-initial <=112 0
readahead-initial <=120 0
readahead-initial <=128 0
readahead-initial <=136 0
readahead-initial <=144 0
readahead-initial <=152 0
readahead-initial <=160 0
readahead-initial <=168 0
readahead-initial <=176 0
readahead-initial <=184 0
readahead-initial <=192 0
readahead-initial <=200 0
readahead-initial <=208 0
readahead-initial <=216 0
readahead-initial <=224 0
readahead-initial <=232 0
readahead-initial <=240 0
readahead-initial <=248 0
readahead-initial >248 0
readahead-state 1331 256 256.010 269
readahead-context 0 0 0.000 0
readahead-contexta 0 0 0.000 0
readahead-backward 0 0 0.000 0
readahead-onthrash 0 0 0.000 0
readahead-onseek 0 0 0.000 0
rescue 0 0 0.000 0
size_drop 13