Re: RAM upgrade abandoned

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.