what is causing system to do page-in/page-out?

what is causing system to do page-in/page-out?

Post by Dave Wrigh » Sat, 10 Jan 1998 04:00:00



vmstat output on a Solaris 2.5 Sparc 20 simultaneously
running many different user batch processes shows a
significant number of pagein's and pageout's per second.
How do I tell whether the I/O is caused by application
I/O to disk, overuse of physical memory (causing page
faults), or ?

The system only has one disk drive so iostat just shows
I/O activity on that drive. User cpu consumption is
around 90% and system cpu consumption is around 5%.
The paging rate is about 100/sec pagein and 300/sec
pageout.

Thanks,
Dave Wright

 
 
 

what is causing system to do page-in/page-out?

Post by David William » Sun, 11 Jan 1998 04:00:00




Quote:>vmstat output on a Solaris 2.5 Sparc 20 simultaneously
>running many different user batch processes shows a
>significant number of pagein's and pageout's per second.
>How do I tell whether the I/O is caused by application
>I/O to disk, overuse of physical memory (causing page
>faults), or ?

  I always though page in/ page out was paging memory,
  thats what page faults are, memory being paged in.

>The system only has one disk drive so iostat just shows
>I/O activity on that drive. User cpu consumption is
>around 90% and system cpu consumption is around 5%.
>The paging rate is about 100/sec pagein and 300/sec
>pageout.

>Thanks,
>Dave Wright


--
David Williams

Maintainer of the Informix FAQ
 Primary site (Beta Version)  http://www.smooth1.demon.co.uk
 Official site                http://www.iiug.org/techinfo/faq/faq_top.html

I see you standin', Standin' on your own, It's such a lonely place for you, For
you to be If you need a shoulder, Or if you need a friend, I'll be here
standing, Until the bitter end...
So don't chastise me Or think I, I mean you harm...
All I ever wanted Was for you To know that I care

 
 
 

what is causing system to do page-in/page-out?

Post by Casper H.S. Dik - Network Security Engine » Mon, 12 Jan 1998 04:00:00


[[ PLEASE DON'T SEND ME EMAIL COPIES OF POSTINGS ]]




>>vmstat output on a Solaris 2.5 Sparc 20 simultaneously
>>running many different user batch processes shows a
>>significant number of pagein's and pageout's per second.
>>How do I tell whether the I/O is caused by application
>>I/O to disk, overuse of physical memory (causing page
>>faults), or ?
>  I always though page in/ page out was paging memory,
>  thats what page faults are, memory being paged in.

I/O is also counted as page in/page outs because of the unification
of the paging and I/O system.

Casper
--
Expressed in this posting are my opinions.  They are in no way related
to opinions held by my employer, Sun Microsystems.
Statements on Sun products included here are not gospel and may
be fiction rather than truth.

 
 
 

what is causing system to do page-in/page-out?

Post by hans maye » Mon, 12 Jan 1998 04:00:00




>[[ PLEASE DON'T SEND ME EMAIL COPIES OF POSTINGS ]]




>>>vmstat output on a Solaris 2.5 Sparc 20 simultaneously
>>>running many different user batch processes shows a
>>>significant number of pagein's and pageout's per second.
>>>How do I tell whether the I/O is caused by application
>>>I/O to disk, overuse of physical memory (causing page
>>>faults), or ?

>>  I always though page in/ page out was paging memory,
>>  thats what page faults are, memory being paged in.

>I/O is also counted as page in/page outs because of the unification
>of the paging and I/O system.

a small part of the executable code ( about 10% )
is hold in the swap, independent how much memory you have in the box.
this results in the moment of proc-forking in paging.



 
 
 

what is causing system to do page-in/page-out?

Post by David William » Mon, 12 Jan 1998 04:00:00




>[[ PLEASE DON'T SEND ME EMAIL COPIES OF POSTINGS ]]




>>>vmstat output on a Solaris 2.5 Sparc 20 simultaneously
>>>running many different user batch processes shows a
>>>significant number of pagein's and pageout's per second.
>>>How do I tell whether the I/O is caused by application
>>>I/O to disk, overuse of physical memory (causing page
>>>faults), or ?

>>  I always though page in/ page out was paging memory,
>>  thats what page faults are, memory being paged in.

>I/O is also counted as page in/page outs because of the unification
>of the paging and I/O system.

 SO how do you tell the different?

Quote:>Casper
>--
>Expressed in this posting are my opinions.  They are in no way related
>to opinions held by my employer, Sun Microsystems.
>Statements on Sun products included here are not gospel and may
>be fiction rather than truth.

--
David Williams

Maintainer of the Informix FAQ
 Primary site (Beta Version)  http://www.smooth1.demon.co.uk
 Official site                http://www.iiug.org/techinfo/faq/faq_top.html

I see you standin', Standin' on your own, It's such a lonely place for you, For
you to be If you need a shoulder, Or if you need a friend, I'll be here
standing, Until the bitter end...
So don't chastise me Or think I, I mean you harm...
All I ever wanted Was for you To know that I care

 
 
 

1. More page outs than page ins?

Hi,

Would anyone be kind enough to explain to me why systems usually have
more page-outs than page-ins? It has got me stumped for quite some
time. I would think that if 100mb is paged out from memory to disk,
then similarly 100mb should be paged-in back from disk to physical
memory?

Or is my understand of paging-in and paging-out wrong? i.e Page-outs
occur when a page is pushed from main memory to the paging space due
to a variety of reasons (lack of physical memory being one of them)
while page-ins' occur when there is free physical memory and these
pages are pushed back from disk back to the physical memory.

TIA!

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