Re: Do I need to be RESIDENT
Would a setting of 1 be the same as -1?
TIA,
Zev Berezin
From: Michael Mueller <m.mueller01.delete_me@kay-mueller.de>
To: informix-list@iiug.org
Subject: Re: Do I need to be RESIDENT
Date sent: Wed, 30 Mar 2005 18:55:38 +0200
Organization: 1&1 Internet AG
Send reply to: Michael Mueller <m.mueller01.delete_me@kay-mueller.de>
> In this case I would expect a real benefit. The operating system has to
> manage every single page of shared memory and has to store and cache
> address mappings for every page. Setting "RESIDENT -1" on Solaris means
> reducing the number of pages by a factor of 512.
>
> I also know a case of a comparable system where "onmode -k" and onstat
> commands became slow until "RESIDENT -1" was used. This was presumably
> caused by the operating system because detaching so many pages of memory
> was a major task.
>
> Michael
>
>
> Colin Dawson wrote:
> > Platform is Solaris 9, 16CPU, 32Gb memory
> >
> >
> >
> > Regards
> >
> > Colin
> >
> >
> >
> >
> >
> >
> >>From: Michael Mueller <m.mueller01.delete_me@kay-mueller.de>
> >>To: Colin Dawson <cjd_1955@hotmail.com>
> >>Subject: Re: Do I need to be RESIDENT
> >>Date: Wed, 30 Mar 2005 14:39:08 +0200
> >>
> >>What platform are you on?
> >>
> >>Making memory resident that is not paged out anyway may not make sense. But
> >>on Solaris the "RESIDENT -1" setting has a second effect: It creates shared
> >>memory with a page size of 4 MB instead of 8k pages (using the
> >>SHM_SHARE_MMU flag of shmat()). This speeds up physical to virtual page
> >>translation in the cpu and has a performance benefit on large systems.
> >>
> >>Michael
> >>
> >>Colin Dawson wrote:
> >>
> >>>We currently have RESIDENT set to -1, if I increase BUFFERS above 2M I get
> >>>the message
> >>>
> >>>07:55:17 Informix Dynamic Server Stopped.
> >>>07:56:49 mt_shm_init: can't create resident segment> >>>
> >>>When I change RESIDENT to 0, I can increase the buffers to whatever I
> >>>want. I know why I'm getting this error, that is not the reason for this
> >>>posting. What I'm looking for is an informed opinion of why set RESIDENT
> >>>to -1 in the first place, Is there a real benefit or only a percieved one?
> >>>
> >>>
> >>>
> >>>
> >>>
> >>>Regards
> >>>
> >>>Colin Dawson
> >>>
> >>>
> >>>sending to informix-list
> >>
> >
> >
> > sending to informix-list
>
sending to informix-list