rec.autos.simulators

Swapfile HELP

Mart

Swapfile HELP

by Mart » Wed, 20 Jun 2001 06:07:26


> http://www.racesimcentral.net/:
> Swap-File myth #1:
> Create a permanent swapfile 2 1/2-3 times the amount of physical
> memory.

> Fact: Virtual memory (Swap-File) is a substitute for physical memory.
> Common sense tells you the more physical memory you have, the less
> virtual memory you need. Conversely (all other things being equal) the
> less physical memory you have the more virtual memory you will need.

ACK.

Well I believe the 2,5x rule of thumb is:
If your system runs fine with a 2,5x RAM size page file under heavy
"normal" load then you've reached some sort of optimal memory point:

Less memory requires a bigger swap file and results in heavy paging (even
inside one application) and a huge performance decrease.

More memory OTOS will increase the systems performance under normal load
only slightly because most things will fit into RAM i.e. paging mostly
occurs when the user start a new program or (infrequently) switches
between large applications.

Of course more RAM (and thus a relativly smaller page file) won't hurt
performance - however the gain isn't that dramatic during normal use.
OTOH Memory intensive applications (like some games) will still benefit a
lot from more memory - up to the point where you don't need a swap file
at all because all your data and apps fit into RAM.

In short: The rule is not: "I have 128 MB RAM so I need 300 MB swap" but
"if the system needs a page file 2,5 times the RAM size to run under heavy
load then you have enough memory for a smooth normal use".

That's how _I_ understand that rule, anyway.

Personally I'd like to have my min and max size the same for this very
reason. When I get the out of memory error I know that my page file is
"full" and that it might be a good idea to avoid using that many programs
at the same time or buy some more RAM.

Just my 0.02

Martin

Jason

Swapfile HELP

by Jason » Wed, 20 Jun 2001 06:50:14

Well that is easy mate.

First... most games nowadays won't run on only 32 MB of RAM.
Second... If you are running your game from a pagefile... chug-chug-chug go
the FPS

Why on earth do you think they only load say "a track at a time" before you
actually race... because they are loading it into RAM.

The gentleman in question was asking a "general topic" question.
Bottom-line... if you are running your game from VM... you need more RAM...
period.

I have found the 2.5x formula to work just great for me in a wide number of
configurations.

If the box has 32 MB of RAM... it isn't all that suited to do a whole heck
of a lot in today's applications anyways.... nevermind games...

As for AGP aperature size, I do not concur with that formula you posted, so
that is moot.

You seem to be getting quite upset about a silly little post from a guy who
simply wanted a solid answer. You tell him "Figure it out yourself...". I
tell him "This is what I have found works best for me...".

Seems to me that YOU are the one here not saying a whole lot constructive
TBH.

Again... not trying to start a war here (the topic is not worth it).

Cheers,

Schumi


> On Mon, 18 Jun 2001 09:47:36 -0700, "Jason \"Schumi\" Murray"

> >"Because the more ram you have then the less swap file will be used."

> >Without attempting to get into a debate/argument over this, this above
> >statement is very false.

> BS. So if I have 32mb of ram then I set my swap file to 80mb? Wake up
> dude. You will have games crashing all over the place. Regardless of
> if you have 32mb or 256mb you will need a larger swap file than 80mb
> for many of todays games. 2.5x ram is a stupid equation for the same
> reason 1/2 your ram for AGP aperature is. Maybe you want to tackle
> that one too?

Jason

Swapfile HELP

by Jason » Wed, 20 Jun 2001 06:50:59

Sorry if I took longer than 15 minutes to respopnd to you... I don't camp
out here day/night awaiting replies...

Cheers,

Schumi


> On Mon, 18 Jun 2001 09:47:36 -0700, "Jason \"Schumi\" Murray"

> >Anyways... m***of the story (sorry for being so long winded) is:

> Geez, for such a long post you didn't really say anything at all. Now
> tell me again why I should use 2.5x my ram?

Scalawa

Swapfile HELP

by Scalawa » Wed, 20 Jun 2001 07:22:04

On Mon, 18 Jun 2001 14:50:14 -0700, "Jason \"Schumi\" Murray"


>You seem to be getting quite upset about a silly little post from a guy who
>simply wanted a solid answer. You tell him "Figure it out yourself...". I
>tell him "This is what I have found works best for me...".

>Seems to me that YOU are the one here not saying a whole lot constructive
>TBH.

And you wouldn't get upset if someone told everyone that what you said
is boillocks even though you know it isn't? I've posted my proof of
why I said what I said. Now where is yours? And i already know that
the more ram you have then the more windows will use for paging. That
still doesn't mean 2.5x is a good number. In fact it is a completely
stupid number and would only maybe apply to running windows itself and
not games.
Scalawa

Swapfile HELP

by Scalawa » Wed, 20 Jun 2001 07:23:22

On Mon, 18 Jun 2001 14:50:59 -0700, "Jason \"Schumi\" Murray"


>Sorry if I took longer than 15 minutes to respopnd to you... I don't camp
>out here day/night awaiting replies...

>Cheers,

>Schumi

How convenient of you to respond to all my posts except the one where
I posted an url that backs up what I say. Why is that Schumi?
Scalawa

Swapfile HELP

by Scalawa » Wed, 20 Jun 2001 07:27:08


Well it is bollocks. We are applying this to ***, no? With your
rule and 128mb of ram you would set your swap file to 320mb. This is
not enough for some of todays games. So your rule is completely
useless.

Mart

Swapfile HELP

by Mart » Wed, 20 Jun 2001 07:40:38



>>That's how _I_ understand that rule, anyway.

> Well it is bollocks. We are applying this to ***, no? With your
> rule and 128mb of ram you would set your swap file to 320mb. This is
> not enough for some of todays games.

Well you're getting me wrong here...
what I said was: if the system doens't run with the 2,5x RAM rule it's time
to buy more RAM.

If a game requires more than 128+320 MB RAM to run then usually the
performance will be very poor with just 128 -> add more RAM until the
system runs again with the 2,5x rule: 256+640 should do the trick for most
games.

Plus I also said for memory intensive apps (like ***) you'd have to
shift that rule into the 1x directrion.

No, it is not - you just have to know how to apply it...

Martin

Peter Ive

Swapfile HELP

by Peter Ive » Wed, 20 Jun 2001 04:21:50



Are you suggesting that windows is busy reading/writing to my swapfile
whilst I'm actually racing GPL or any other CPU intensive game?  I
seriously doubt this as I would suspect that any kind of other PC
activity would slow up my *** experience quite noticeably whether
I've attempted to optimise my swapfile or not.

<snip>
--
Peter Ives
Remove ALL_STRESS before replying
If you know what's good for you, don't listen to me
GPLRank Joystick -50.63 Wheel -14.08

+G2

Swapfile HELP

by +G2 » Wed, 20 Jun 2001 10:36:34



 There's nothing brutal or false about it.  They designed it to manage it
all on it's own.
I'm not saying dynamic is best, but dynamic does work on some machines just
fine and dandy.

If its dynamically resizing the swap during a race, I'd suspect something
else is up with your system.  GPL is very well behaved in my experience.
WinVROC or another background program might be up to something, I wouldn't
suspect GPL as the sole cause.
It seems quite stable on my system.

Seems to me that accessing any swap file, dynamic or static, will use CPU
cycles and HD activity.

If this isn't on a separate drive what performance increase did you just
gain?
It's now got to go to another partition on the same disk to access the swap.

If it's on a single spindle the only performance increase I've ever heard
was to insure the swap file is at the center of the drive (if possible) and
go static like you say, but only IF you're having issues.
I've heard that putting the swap on a separate, physical drive helps.

I guess your not going to answer the question about the 2.5 figure?   I've
yet to hear a definitive answer anyway.
I've seen 1.5, 2.0, 2.5, 3.0, etc. listed.  It's a good number as any,
however I've yet to see a MS knowledge base article on this.
Surely someone's benchmarked this somewhere, love to see it.

http://www.bootdisk.com/swapfile.htm  This guy points out a way to determine
what swap you need.
Sounds like you can measure things a bit if you want.

Good idea in SOME cases, even better on a separate drive.

This can be an issue, however using the right defragger you can also defrag
your swap.
I'm usually more concerned about defragging all my files not just the swap
file.

Depending where this partition is located you may have the exact opposite
effect anyway, especially if your files are at the opposite end of the
platters from your swap file.

Saving CPU cycles sounds great and is great.
Most games access the drive some of the time anyhow, retrieving textures,
with any disk activity, you can't stop using CPU cycles unfortunately.

I see this being more of an issue if something was wrong with the app and
the swap kept growing.
I've seen many a desktop get into swap file hell once they pushed a program
too far.
Usually because they tried to load every bit of tool software they own at
the same time.

Your explaining one example of how a swap file is used, how would dynamic or
static differ in this case.
What I see, is that in your case with a static, it may not have enough room
to dump the "rouge memory allocations".
Surely there's some reason they recommend that you let Windows manage it.

I'm sure that MS OS's have memory leaks, however they certainly don't always
manifest themselves regularly.
Well not with 2000 at least, it's been excellent, can't say the same thing
about some of it's applications though.

My swap file is dynamic, I've been playing GPL for a month or so, amongst
other diversions.
It hasn't significantly changed its size, still at 400MB.  Good GPL.

I've haven't had a "out of memory" error in years either.
Well since Windows 3.1 anyway.
All while using a dynamic swap files (servers included, Windows
95/98/ME/NT/2000).

Exactly, to call something "a bit false" wasn't fair IMO.
What works for you may not work for others.
There are too many permutations and combinations of hardware/software/OS's
for absolutes.

+G2

Swapfile HELP

by +G2 » Wed, 20 Jun 2001 10:44:29



There's nothing brutal or false about it.  They designed it to manage it
all on it's own.

I'm not saying dynamic is best, but dynamic does work on some machines just
fine and dandy.

If its dynamically resizing the swap during a race, I'd suspect something
else is up with your system.  GPL is very well behaved in my experience.
WinVROC or another background program might be up to something, I wouldn't
suspect GPL as the sole cause. It seems quite stable on my system.

Seems to me that accessing any swap file, dynamic or static, will use CPU
cycles and HD activity.

If this isn't on a separate drive what performance increase did you just
gain?  It's now got to go to another partition on the same disk to access
the swap.

If it's on a single spindle the only performance increase I've ever heard
was to insure the swap file is at the center of the drive (if possible) and
go static like you say, but only IF you're having issues.
I've heard that putting the swap on a separate, physical drive helps.

I guess your not going to answer the question about the 2.5 figure?   I've
yet to hear a definitive answer anyway.
I've seen 1.5, 2.0, 2.5, 3.0, etc. listed.  It's a good number as any,
however I've yet to see a MS knowledge base article on this.
Surely someone's benchmarked this somewhere, love to see it.

Good idea in SOME cases, even better on a separate drive.

This can be an issue, however using the right defragger you can also defrag
your swap.
I'm usually more concerned about defragging all my files not just the swap
file.

Depending where this partition is located you may have the exact opposite
effect anyway, especially if your files are at the opposite end of the
platters from your swap file.

Saving CPU cycles sounds great and is great.
Most games access the drive some of the time anyhow, retrieving textures,
with any disk activity, you can't stop using CPU cycles unfortunately.

I see this being more of an issue if something was wrong with the app and
the swap kept growing.
I've seen many a desktop get into swap file hell once they pushed a program
too far.
Usually because they tried to load every bit of tool software they own at
the same time.

Your explaining one example of how a swap file is used, how would dynamic or
static differ in this case.
What I see, is that in your case with a static, it may not have enough room
to dump the "rouge memory allocations".
Surely there's some reason they recommend that you let Windows manage it.

I'm sure that MS OS's have memory leaks, however they certainly don't always
manifest themselves regularly.
Well not with 2000 at least, it's been excellent, can't say the same thing
about some of it's applications though.

My swap file is dynamic, I've been playing GPL for a month or so, amongst
other diversions.
It hasn't significantly changed its size, still at 400MB.  Good GPL.

I've haven't had a "out of memory" error in years either.
Well since Windows 3.1 anyway.
All while using a dynamic swap files (servers included, Windows
95/98/ME/NT/2000).

Exactly, to call something "a bit false" wasn't fair IMO.
What works for you may not work for others.
There are too many permutations and combinations of hardware/software/OS's
for absolutes.

+G2

Swapfile HELP

by +G2 » Wed, 20 Jun 2001 10:51:02



You're describing how the OS can monitor and tunes itself, to me this makes
even more sense to let it manage the swap.

Yes and it's not just used for VM allocation, it's also used for thread
prioritization.
As important or more so.

Enditall, end of story!  ;-)

Agreed, static or dynamic, it's used (ie. using CPU cycles) all the time.

+G2

Swapfile HELP

by +G2 » Wed, 20 Jun 2001 10:53:31

Why use a magic formula.

This guys shows a potential way to measure what you may require.

http://www.bootdisk.com/swapfile.htm

Thom j

Swapfile HELP

by Thom j » Wed, 20 Jun 2001 11:39:46

Thanx for the Url +G2!! I have a fixed max-min file for memory of 1gig!
Maybe I am doing "overkill" and using too much HD space since I have
512megs of PC133Dram? Going to read the info now.. :-) Thom_j.


| Why use a magic formula.
|
| This guys shows a potential way to measure what you may require.
|
| http://www.bootdisk.com/swapfile.htm
|
|

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Scalawa

Swapfile HELP

by Scalawa » Wed, 20 Jun 2001 13:05:57


I still say bollocks mate. And I posted an url with backup to my claim
and you still refute it.


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