[K12OSN] bottleneck question

[Liam Marshall]

Les Mikesell wrote:

>On Wed, 2004-09-08 at 21:46, Liam Marshall wrote:
>  
>
>>>It is the activity more than the amount that will slow you
>>>down - loaded but inactive programs that are paged out
>>>don't hurt much.  Do a 'vmstat 5' so you see snapshots
>>>every 5 seconds and if the 'si' and 'so' numbers show
>>>paging activity in normal operation then RAM will help.
>>>
>>> 
>>>      
>>>
>>thanks for the input,  but I just don't  no how to interpret  what you 
>>said.  I will check to si and so numbers, but how do I interpret them?
>>    
>>
>
>It shows the blocks of memory being swapped out (so) to disk and 
>back in (si) in KB/s.   You can tolerate some unused parts of
>large programs being swapped out to gain virtual memory space,
>but if the memory for active programs is threshing to disk
>memory access effectively slows down to disk speed.
>
>You will also see the cpu use and idle time.  If your swap
>partition is on an efficient scsi disk you might see the
>cpu have a fairly high idle percentage while the system
>waits for disk access.  With an IDE system you might see
>high cpu use along with swap activity.   If you see high
>cpu use (low idle percentage) and little swapping, it
>won't help much to add RAM.
>
>  
>


thanks, I will look into that