howdy,
In /proc/stat the record as
page x y
which indicates cumulative page in and out values.
To my best undertstanding this info is stored in
kstat.pgpgin and kstat.pgpgout.
However the values are incremented in submit_bh in
ll_rw_blk.c. So are we actually counting the buffers
we write in and out or the pages; or is it the same ?
thanks
Ravi
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On Fri, 12 Apr 2002, Ravi Wijayaratne wrote:
| In /proc/stat the record as
|
| page x y
|
| which indicates cumulative page in and out values.
| To my best undertstanding this info is stored in
| kstat.pgpgin and kstat.pgpgout.
|
| However the values are incremented in submit_bh in
| ll_rw_blk.c. So are we actually counting the buffers
| we write in and out or the pages; or is it the same ?
Please see if
http://marc.theaimsgroup.com/?l=linux-kernel&m=101770318012189&w=2
answers your questions.
--
~Randy
There was a follow-on answer to this set of questions. Briefly, in
/proc/stat, there are two lines: page <in> <out> and swap <in> <out>. The
"page" values are in kilobytes and the "swap" values are in pages. *And*,
every byte in the "swap" values is double-counted in the "page" values as
well. So, to interpret these numbers, multiply the "page" values by 1024 and
the "swap" values by the page size in bytes. Then subtract the swap values
from the "page" values, and you'll have the number of bytes to and from swap
space and the number of bytes to and from everything else.
One other little note: later on in /proc/stat, there will be a line
containing entries for the individual disks. Those entries count operations,
reads, writes, read "blocks" and write "blocks". In these entries, a "block"
is 512 bytes.
> -----Original Message-----
> From: [email protected]
> [mailto:[email protected]]On Behalf Of Randy.Dunlap
> Sent: Friday, April 12, 2002 2:23 PM
> To: Ravi Wijayaratne
> Cc: [email protected]
> Subject: Re: /proc/stat page in and out values
>
>
> On Fri, 12 Apr 2002, Ravi Wijayaratne wrote:
>
> | In /proc/stat the record as
> |
> | page x y
> |
> | which indicates cumulative page in and out values.
> | To my best undertstanding this info is stored in
> | kstat.pgpgin and kstat.pgpgout.
> |
> | However the values are incremented in submit_bh in
> | ll_rw_blk.c. So are we actually counting the buffers
> | we write in and out or the pages; or is it the same ?
>
> Please see if
> http://marc.theaimsgroup.com/?l=linux-kernel&m=101770318012189&w=2
> answers your questions.
>
> --
> ~Randy
>
> -
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>