Tech Support > Computer Hardware > Storage Devices > Optimum page file size for 1 GB?
Optimum page file size for 1 GB?
Posted by Terry Pinnell on March 21st, 2007


I just upgraded my Athlon 1800 512 MB to 1 GB. Is there any general
consensus on the 'best' setting I should use for page file please? I
recall a few years ago much debate/controversy over this, but wonder
if a consensus has now emerged? My CPU is now slow by today's
standards (runs at 1533 MHz), so I naturally want to get the most out
of this extra RAM.

--
Terry, West Sussex, UK

Posted by Bob Willard on March 21st, 2007


Terry Pinnell wrote:

I think the consensus is, for almost all XP desktop PCs, to let the OS
control the size dynamically.

--
Cheers, Bob

Posted by Arno Wagner on March 21st, 2007


Previously Bob Willard <BobwBSGS@trashthis.comcast.net> wrote:
Not at all. Good performance requires a static size. No control
by the OS then.

Arno

Posted by Terry Pinnell on March 21st, 2007


Arno Wagner <me@privacy.net> wrote:

Thanks both. Hmm, so I suspect things haven't changed then - still no
consensus!

--
Terry, West Sussex, UK

Posted by Alexander Grigoriev on March 21st, 2007


Not quite. It doesn't hurt much to have a static PF larger than necessary,
but it's no better than to have Windows extend the PF as needed. A pagefile
is not shrunk back when extra is no more needed, so there is no penalty of
changing the size back and forth.
The only issue is that the PF may get slightly fragmented. As long as it's
not tens of pieces, it should not hurt.

One issue (important mostly to kernel component developers) is that the
pagefile should be at least as big as RAM size, to allow full crash dump.
Even for normal users, some crappy video drivers sometimes crash, and to
allow automated post-mortem analysis, the crash dump needs to be saved.

"Arno Wagner" <me@privacy.net> wrote in message
news:56ctqbF28qiavU1@mid.individual.net...


Posted by Eric Gisin on March 21st, 2007


"Annie Wagner" <me@privacy.net> wrote in message news:56ctqbF28qiavU1@mid.individual.net...
What a fucking maroon.

The only version of windows this was valid for was Win 3,
where permanent, contigous pagefile bypassed FAT and
had lower overhead than the temporary pagefile.



Posted by Arno Wagner on March 21st, 2007


Previously Terry Pinnell <terrypinDELETE@thesedial.pipex.com> wrote:
Hehe. Here is one rule of thumb that I use: Swap should be the same size
as the main memory, but not larger than 256MB, since it then starts to
take forever to actually use it.

My Linux currently runns swappless without issue. For XP, I think
I have 250MB static size.

Arno

Posted by Arno Wagner on March 21st, 2007


Previously Alexander Grigoriev <alegr@earthlink.net> wrote:
Well, If you are a developer....

I don't think that is relevant for most users.

Arno




Posted by Frazer Jolly Goodfellow on March 21st, 2007


Michael Cecil <macecil@gmail.com> wrote in
news:ab-dnTUKbcIZAZzbnZ2dnUVZ_hmtnZ2d@comcast.com:



Posted by Alexander Grigoriev on March 22nd, 2007


Then it's like you don't have a swapfile at all.
Windows is using different physical to pagefile mapping. First, it doesn't
allow overcommit, unlike *ix OSs. All committed pageable RAM pages map to
pagefile pages. As soon as a page needs to be swapped out, it's written to
PF. Then the RAM page becomes free to read another page.

Bottom line, total virtual memory size is NOT RAM+PF. It's max(RAM, PF).

"Arno Wagner" <me@privacy.net> wrote in message
news:56d9umF28gvnpU2@mid.individual.net...


Posted by Arno Wagner on March 22nd, 2007


Previously Alexander Grigoriev <alegr@earthlink.net> wrote:
Ok, that is plain stupid. They should have read some introductory
text on OS memory management! If MS really does not know ho to do this
properly and implemented it this way, then your are correct, of course.

So in Windows, you cannot use more memory than you have physically
available? Unbelivable! That was the reason pageing was invented in the
first place!

Well, I usually only run single taks in XP (games), so I will probably
not be too much affected. Nut I now understand why a webbrowser run in
paralell can lead to memory exhaustion. Why does MS always have to
ignore technology prooven over decades and do their own inferiour and
botched thing? Does nobody there study first what already exists?
Extremely incompetent or extremely arrogant. Maybe both.

Arno






Posted by timeOday on March 22nd, 2007


Arno Wagner wrote:
I've run without swap space on Linux for years now. I think swap is an
idea whose time has passed.

Posted by Aidan Karley on March 22nd, 2007


In article <56e8bdF28hg9dU1@mid.individual.net>, Arno Wagner wrote:
a 128MB memory machine (more than adequate for normal purposes) and a 256MB
swap file ... you have 256 MB of memory available to processes and OS. Not
384MB as you might expect.

programmers who might be infected with prior art. Sorry, "infested", not
"infected". Well, actually, both.
Maybe that would explain the high hiring rates of programmers - once
a programmer has been exposed to other programmer's work, there's the
possibility of a patent violation and the programmer can't be used again.
Single-shot disposable programmers. Now there's an idea.
--
Aidan Karley
Aberdeen, Scotland
Written at Thu, 22 Mar 2007 08:44 GMT, but posted later.


Posted by Aidan Karley on March 22nd, 2007


In article <tZ6dnenvX-0icJzbnZ2dnUVZ_ozinZ2d@comcast.com>, TimeOday wrote:
a serious application fault, without fear of overwriting work by any other
process. As far as that goes, the idea is very much alive and well. In
fact, making swap a distinct partition is a very good idea. (It can also
be used for dumping core to in the event of a kernel fault.)
Have you checked that your kernel isn't creating a swap *file*
without you noticing - the Linux virtual memory manager has the ability to
dynamically add swap as either partitions *or* as files in an existing
filesystem. I recall that this used to be the case in the 1.x series of
kernels, but I've not bothered learning the ins and outs in 2.x series.

--
Aidan Karley
Aberdeen, Scotland
Written at Thu, 22 Mar 2007 08:55 GMT, but posted later.


Posted by chrisv on March 22nd, 2007


Michael Cecil wrote:

Wrong.


Posted by Folkert Rienstra on March 22nd, 2007


"Arno Wagner" <me@privacy.net> wrote in message news:56e8bdF28hg9dU1@mid.individual.net
And you obviously have been talking from your arse again, as usual.

Brainfarct again, babblebot? The howmaniest this week?

Like yourself, babblebot? No wonder that you don't work there.

Posted by Arno Wagner on March 22nd, 2007


Previously Aidan Karley <name1_name2@email.provider.invalid> wrote:
Under UNIX the kernel dumps to file. Swap is not unsed for that.
No idea why Windows is incapable of producing a dump-file (i you
are right that it is).

But id does not do so it unless you tell it to. And at leats in
Debian nobody has scripted in some hidden ''magic''. Most likely
users would be quite offended if somebody did.

The kernel never did this. It may have activates swap automatically
if started with the right options, but it never created swap space
on its own.

Arno


Posted by Alexander Grigoriev on March 22nd, 2007


What would you say of an OS that does randomly kill a process when it needs
to get a VM page when a previous allocation already reported as succeeded?
This is what *ix OSs do in case of overcommit. They allocate virtual memory
vithout caring if there is enough pagefile to support it. This is done to
make fork() succeed. For a forked process pair, all pages become shared and
marked as copy on write. They don't get separate pages in PF alocated yet.
Thus, amount of committed memory may exceed amount of available VM. When
there is no need to actually use PF (no copy on write happened yet), it's
OK. When COW happens, PF page gets allocated. If it was impossible to
allocate PF page, the OS just kills some process. Talk to me about
introductory text on good design.

Regarding Windows, I said max(RAM, PF), not min(RAM, PF).

"Arno Wagner" <me@privacy.net> wrote in message
news:56e8bdF28hg9dU1@mid.individual.net...


Posted by Alexander Grigoriev on March 22nd, 2007


When kernel bugcheck occurs, it's not a good idea to go to filesystem and
create a file. After all, your filesystem driver may be screwed all over by
a faulty driver that caused the crash. If you call it, it might as well say
goodbye to the whole partition.

In Windows, crash dump is written by a special part of the disk driver,
which is normally not even mapped to kernel space, to avoid its corruption.
Position to where to write the dump is known beforehand, during pagefile
initialization. When crash dump starts, bugcheck handler maps the dump
writer which then does the job.

"Arno Wagner" <me@privacy.net> wrote in message
news:56fodtF292conU1@mid.individual.net...


Posted by timeOday on March 22nd, 2007


Alexander Grigoriev wrote:
Kernel dumps are certainly something I'm willing to sacrifice. I have
no use for them.


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