Re: RAM upgrade abandoned

----- Original Message ----- 
From: "Keith Smith"

> Roy wrote:
> >>>I actualy dont see any big reason to upgrade ram
> 4mb
> >>
> >> > is quite enough it will not improve speed at
> all
> >>
> >>I don't think so... Keith states all the time that
> >>using external SWAP improves the responsiveness
> >>of linuxap. add more RAM is an alternative to
> SWAPing,
> >>or am I missing something here?
> >>
> >
> >
> > I cant state that adding more ram will not improve anyting, but
> it wont
> > improve speed so much
> > the main job is done in kernel space wich is not swapable
> anyway.
> > so all you will improve is telnet and web management
> response.
> > throughput will not change at all, it depends only on cpu
> speed.
> > so unless you need to run userspace programs there is no need
> for more ram.
> > afterall there is at least 1mb free because you can download
> flash image
> > into ram
>
> It's thrashing.  The ROM filesystem is block *compressed*.  The kernel
> buffer cache will read & decompress the block ( cpu cycles ), but it
> can't keep it around because there is no memory to leave it in, so
> the buffer cache get's flushed *constantly*.  Further reading from the
> flash memory is much slower than ram (access time), and you have to
> waste CPU cycles decompressing the same blocks over and over again.
>
> Occasionally used .TEXT pages (say syslog?, dhcp?), sit and hog up
> RAM, narrowing the available buffer cache.  Further I think there are
serious
> issues with linux and memory management when the kernel runs out of
memory.
> I've gotten '"'Out of Memory'"' errors when it would appear that there was
> available memory.
>
> Another 4MB of RAM would improve performance *dramatically*.  We are
talking
> 486SX-33 chip here.  It should be able to keep up a lot more easily.
>
> >
> >
> >>>another thing is flash which is very thight on
> space
> >>
>
> I've maintained 2MB Flash / 8MB RAM would be an acceptable trade-off.
> The problem is, this is a dead board.
>

Yes unfortunately this platform is dead, so no need to improve it.
But it is very strange that so many people are talking about performance
improvement
without any explanation what performance they want to improve
this ap because of so small flash memory cant do anything besides routing or
bridging
even pppoe wont fit. (and actualy can be done in kernel space anyway).

I am just interested what userspace programs you are running?
the only purpose of userspace for me is to configure everything and run
telnet and web server.
I dont think syslog or dhcp is usefull actualy dhcp decresses security alot
and you cant control anything anymore
anyway it dont take so much ram space.