OS Performance (was OT: New low for Microsoft!)

Jeff Vian jvian10 at charter.net
Wed May 5 22:40:03 UTC 2004

bugler at teuton.org wrote:

>>>A good example is switching windows.  Everything is loaded in RAM -- 
>>>no caching to the HD.  When I change the focus to another open window, 
>>Yes, it is normal on ALL OSes on systems that are underpowered.  Yours 
>>has inadequate ram and is likely using a lot of swap so performance 
>>takes a major hit.  Spring the $40 or so and get an additional 256mb ram 
>>and see the huge difference.
>I don't think that this is the case, and here is why:  When running the system 
>monitor for this test there is about 111 MB of 128 MB physical RAM being used.  
>On the hard drive there is a 256 MB swap allocated, and about 56 MB being used.
>When I switch focus from one window to another (e.g. say from Mozilla to 
>Mozilla Mail) there is about a 400-500 ms lag.  The RAM is _NOT_ caching to the 
>hard drive for info -- the HD light never flickers.
>So, with all due respect, I have a hard time believing that swapping is the 
>problem in this instance.  If I were switching between Calc and Mozilla --- 
>listening to the HD crank away --- then yes it is clearly a RAM issue.  But in 
>this case, I'm not so sure.
Mozilla is not the bug memory hog, X is.
Remember, when you are running X, the total memory used /before/ you 
start any applications is the kernel space, X and its supporting 
processes, the services that you are running, and your login processes.
Add to that the overhead of starting user space applications and 128MB 
becomes very tiny.
IIRC the minimum to even install FC1 is 128MB and more is better.

I would suggest you try the inexpensive route of adding more memory just 
to see the difference.  I think you will be pleasantly surprised..

>Is it possible that there's some hardware acceleration (on my box) that Windows 
>is utilizing and Linux is not.  I'm using an Intel 810 graphics card.
That is always possible but I don't know..

However on my system I see the slowdown frequently, but not continuously.
In my case, I am running seti 24X7 and the CPU runs at 100% constantly. 
 After being away from the machine for some time and coming back, the 
first few minutes after I start using it the response is very slow.  I 
attribute this to the way linux uses swap and caches processes because 
after the first few minutes it has reorganized data in memory cache/swap 
and speeds back up and runs normally.
I am running 512mb ram and use about 90mb swap after 2 weeks of running 
with my normal habits.

I wish linux had some performance monitoring tools like AIX.  IBMs 
vmstat provides a lot of information about what has ocurred with paging, 
disk io, as well as cpu usage.  If linux was able to provide similar 
monitoring tools these problems would be easier to identify.


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