Re: [PATCH] Introduce block I/O performance histograms

[Jens Axboe <jens.axboe@oracle.com>]

On Wed, Nov 15 2006, Edward Falk wrote:
> This patch introduces performance histogram record keeping for block 
> I/O, used for performance tuning.  It is turned off by default.
> 
> When turned on, you simply do something like:
> 
> # cat /sys/block/sda/read_request_histo
> rows = bytes columns = ms
>         10      20      50      100     200     500     1000    2000
>    2048 5       0       0       0       0       0       0       0
>    4096 0       0       0       0       0       0       0       0
>    8192 17231   135     41      10      0       0       0       0
>   16384 4400    24      6       2       0       0       0       0
>   32768 2897    34      4       4       0       0       0       0
>   65536 7089    87      5       1       2       0       0       0

I don't see the point at all for including this piece of code in the
kernel. You can do the same from user space. Your help entry said it
even grows the kernel size about 21k, that's pretty nasty.

So NAK.

-- 
Jens Axboe

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