More memory == better?

More memory == better?

[DevilKin]

Hello All,

Currently I've got myself a nice setup (amd 1.4ghz, abit kg7raid etc etc) 
with 512mb ram... (DDR). I'm wondering if increasing this to 1gb has 
advantages (speedwise or anything), since I can get my hands on it at a very 
low price...

I must say that even with most of my applications loaded/running, the system 
never even touches the swap partition.

So, would it be wise?

Thanks for any info

DevilKin
-- 
devilkin@gmx.net

Re: More memory == better?

[antirez]

On Tue, Oct 23, 2001 at 06:10:38PM +0200, DevilKin wrote:
[snip]
> I must say that even with most of my applications loaded/running, the system 
> never even touches the swap partition.
> 
> So, would it be wise?

If the applications you run are very disk-intensive probably the
answer is yes, since free memory is used as disk cache.

-- 
Salvatore Sanfilippo <antirez@invece.org>
http://www.kyuzz.org/antirez
finger antirez@tella.alicom.com for PGP key
28 52 F5 4A 49 65 34 29 - 1D 1B F6 DA 24 C7 12 BF

Re: More memory == better?

[DevilKin]

On Tuesday 23 October 2001 18:15, antirez wrote:
> On Tue, Oct 23, 2001 at 06:10:38PM +0200, DevilKin wrote:
> [snip]
>
> > I must say that even with most of my applications loaded/running, the
> > system never even touches the swap partition.
> >
> > So, would it be wise?
>
> If the applications you run are very disk-intensive probably the
> answer is yes, since free memory is used as disk cache.

Not really no... Just the average desktop stuff...  some programming now and 
again... 

And games ofcourse :-)

DK

-- 
devilkin@gmx.net

Re: More memory == better?

[David Lang]

also remember that without the himem support you only loose 64M or so
(960MB instead of 1024MB IIRC). not the end of the world if you don't run
the himem kernel.

David Lang



On Tue, 23 Oct 2001, DevilKin wrote:

> Date: Tue, 23 Oct 2001 22:04:12 +0200
> From: DevilKin <DevilKin@gmx.net>
> To: davidsen@tmr.com, linux-kernel@vger.kernel.org
> Subject: Re: More memory == better?
>
> On Tuesday 23 October 2001 21:49, bill davidsen wrote:
> > In article <20011023161340.02EAC9BD76@pop3.telenet-ops.be>,
> >
> > DevilKin <DevilKin@gmx.net> wrote:
> > | Currently I've got myself a nice setup (amd 1.4ghz, abit kg7raid etc etc)
> > | with 512mb ram... (DDR). I'm wondering if increasing this to 1gb has
> > | advantages (speedwise or anything), since I can get my hands on it at a
> > | very low price...
> > |
> > | I must say that even with most of my applications loaded/running, the
> > | system never even touches the swap partition.
> > |
> > | So, would it be wise?
> >
> > There are some good reasons to add memory.
> >
> > - disk i/o rates. vmstat will tell you some disk i/o rates, if they are
> > high you *may* get better performance with more memnory for cache.
> >
> > - future applications. As you say it's cheap right now, if you think
> > there's a good chance of larger images, more kernel compiles, whatever,
> > buy now.
> >
> > - memory bandwidth. This is very motherboard dependent, read your specs.
> > Some systems will use two or four way interleave to increase bandwidth
> > to memory or reduce access time. See what your m/b spec tells you.
> >
> > - you have the money and want to spend it on {something}! Go ahead,
> > memory is one of the best investments for any system.
> >
> > Just remember that to use this memory you need a large memory kernel.
>
> Ah, thats with HIGHMEM support? I've read a lot of awful things about it
> here... how stable (aka usable) is it?
>
> DK
> --
> devilkin@gmx.net
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Re: More memory == better?

[bill davidsen]

In article <20011023161340.02EAC9BD76@pop3.telenet-ops.be>,
DevilKin <DevilKin@gmx.net> wrote:

| Currently I've got myself a nice setup (amd 1.4ghz, abit kg7raid etc etc) 
| with 512mb ram... (DDR). I'm wondering if increasing this to 1gb has 
| advantages (speedwise or anything), since I can get my hands on it at a very 
| low price...
| 
| I must say that even with most of my applications loaded/running, the system 
| never even touches the swap partition.
| 
| So, would it be wise?

There are some good reasons to add memory.

- disk i/o rates. vmstat will tell you some disk i/o rates, if they are
high you *may* get better performance with more memnory for cache.

- future applications. As you say it's cheap right now, if you think
there's a good chance of larger images, more kernel compiles, whatever,
buy now.

- memory bandwidth. This is very motherboard dependent, read your specs.
Some systems will use two or four way interleave to increase bandwidth
to memory or reduce access time. See what your m/b spec tells you.

- you have the money and want to spend it on {something}! Go ahead,
memory is one of the best investments for any system.

Just remember that to use this memory you need a large memory kernel.

-- 
bill davidsen <davidsen@tmr.com>
  His first management concern is not solving the problem, but covering
his ass. If he lived in the middle ages he'd wear his codpiece backward.

Re: More memory == better?

[DevilKin]

On Tuesday 23 October 2001 21:49, bill davidsen wrote:
> In article <20011023161340.02EAC9BD76@pop3.telenet-ops.be>,
>
> DevilKin <DevilKin@gmx.net> wrote:
> | Currently I've got myself a nice setup (amd 1.4ghz, abit kg7raid etc etc)
> | with 512mb ram... (DDR). I'm wondering if increasing this to 1gb has
> | advantages (speedwise or anything), since I can get my hands on it at a
> | very low price...
> |
> | I must say that even with most of my applications loaded/running, the
> | system never even touches the swap partition.
> |
> | So, would it be wise?
>
> There are some good reasons to add memory.
>
> - disk i/o rates. vmstat will tell you some disk i/o rates, if they are
> high you *may* get better performance with more memnory for cache.
>
> - future applications. As you say it's cheap right now, if you think
> there's a good chance of larger images, more kernel compiles, whatever,
> buy now.
>
> - memory bandwidth. This is very motherboard dependent, read your specs.
> Some systems will use two or four way interleave to increase bandwidth
> to memory or reduce access time. See what your m/b spec tells you.
>
> - you have the money and want to spend it on {something}! Go ahead,
> memory is one of the best investments for any system.
>
> Just remember that to use this memory you need a large memory kernel.

Ah, thats with HIGHMEM support? I've read a lot of awful things about it 
here... how stable (aka usable) is it?

DK
-- 
devilkin@gmx.net

Re: More memory == better?

[bill davidsen]

In article <20011023200715.AEF66217593@tartarus.telenet-ops.be>,
DevilKin <DevilKin@gmx.net> wrote:

| > There are some good reasons to add memory.
| >
| > - disk i/o rates. vmstat will tell you some disk i/o rates, if they are
| > high you *may* get better performance with more memnory for cache.
| >
| > - future applications. As you say it's cheap right now, if you think
| > there's a good chance of larger images, more kernel compiles, whatever,
| > buy now.
| >
| > - memory bandwidth. This is very motherboard dependent, read your specs.
| > Some systems will use two or four way interleave to increase bandwidth
| > to memory or reduce access time. See what your m/b spec tells you.
| >
| > - you have the money and want to spend it on {something}! Go ahead,
| > memory is one of the best investments for any system.
| >
| > Just remember that to use this memory you need a large memory kernel.
| 
| Ah, thats with HIGHMEM support? I've read a lot of awful things about it 
| here... how stable (aka usable) is it?

I have 12 machines using it, at seven location in six states... don't
see any problems with which I don't see without. They are all actively
using large files as well, typically 50-100GB.

Looks good to go on my systems.

-- 
bill davidsen <davidsen@tmr.com>
  His first management concern is not solving the problem, but covering
his ass. If he lived in the middle ages he'd wear his codpiece backward.

Re: More memory == better?

[J Sloan]

DevilKin wrote:

> On Tuesday 23 October 2001 21:49, bill davidsen wrote:
>
> > Just remember that to use this memory you need a large memory kernel.
>
> Ah, thats with HIGHMEM support? I've read a lot of awful things about it
> here... how stable (aka usable) is it?

I have 2 observations -

If you don't enable highmem support, you'll
be able to use about 960 MB of your 1 GB -
no big loss, right?

I've been running on a couple machines
with SMP and the 4 GB option, and they
seem quite stable (there was a highmem
bug in the preempt patch, but that is fixed
in the most recent release)

All things considered, it works quite well.

cu

jjs

Re: More memory == better?

[Jens Axboe]

On Tue, Oct 23 2001, bill davidsen wrote:
> In article <20011023161340.02EAC9BD76@pop3.telenet-ops.be>,
> DevilKin <DevilKin@gmx.net> wrote:
> 
> | Currently I've got myself a nice setup (amd 1.4ghz, abit kg7raid etc etc) 
> | with 512mb ram... (DDR). I'm wondering if increasing this to 1gb has 
> | advantages (speedwise or anything), since I can get my hands on it at a very 
> | low price...
> | 
> | I must say that even with most of my applications loaded/running, the system 
> | never even touches the swap partition.
> | 
> | So, would it be wise?
> 
> There are some good reasons to add memory.
> 
> - disk i/o rates. vmstat will tell you some disk i/o rates, if they are
> high you *may* get better performance with more memnory for cache.
> 
> - future applications. As you say it's cheap right now, if you think
> there's a good chance of larger images, more kernel compiles, whatever,
> buy now.
> 
> - memory bandwidth. This is very motherboard dependent, read your specs.
> Some systems will use two or four way interleave to increase bandwidth
> to memory or reduce access time. See what your m/b spec tells you.
> 
> - you have the money and want to spend it on {something}! Go ahead,
> memory is one of the best investments for any system.
> 
> Just remember that to use this memory you need a large memory kernel.

There's also the argument that you may slow down your system by adding
more memory, since with 1G you will have high memory which needs to be
kmap'ed to be accessed by the kernel. For I/O it needs to be bounced to
lower memory, which is even worse.

-- 
Jens Axboe

Re: More memory == better?

[Dirk Moerenhout]

On Tue, 23 Oct 2001, J Sloan wrote:

> If you don't enable highmem support, you'll
> be able to use about 960 MB of your 1 GB -
> no big loss, right?

Actually if you wish you can use your full 1GB just fine without HIGHMEM:

In /proc/meminfo:
MemTotal:      1025360 kB
LowTotal:      1025360 kB

At boot:
kernel: On node 0 totalpages: 262128
kernel: zone(0): 4096 pages.
kernel: zone(1): 258032 pages.
kernel: zone(2): 0 pages.

The related config parameters:
CONFIG_NOHIGHMEM=y
# CONFIG_HIGHMEM4G is not set
# CONFIG_HIGHMEM64G is not set
# CONFIG_1GB is not set
CONFIG_2GB=y
# CONFIG_3GB is not set

For what I know this trick just limits you on the amount of swap you can
have. The suggestion came from Ingo Molnar and it works fine for me.

Dirk Moerenhout ///// System Administrator ///// Planet Internet NV