[X4U] Having Windows open drain resources?

[Ed Gould]

On Apr 6, 2009, at 5:28 PM, Eugene wrote:
> ------------------------- 
> SNIP------------------------------------------
> There are days I wish OS X was more aggressive towards  
> consolidating swap.
>
>
>
Eugene…
I agree. That also assumes a few things that are not apparent (at  
least from an outsiders view).
One of the things swapping does is do BURST mode (that is many  
contagious frames that are needed to be swapped out and in smaller  
systems that is not always easy to tell (from an OS perspective that  
is) To run a robust paging system you need a lot more information  
than "should we swap it". You need when was it last used and *IF* it  
was altered. If it was not altered then there is no reason to page it  
out, as if the page is needed again it can just be recalled from  
where it was the last time. There are also items that the OS needs to  
give to the paging system like is there a paging shortage (Y/N) what  
tasks are waiting to be paged/swapped in. How much  
"free" (unallocated) storage is there. Is there a lot of demand  
paging (task(s) are waiting for a page in to take place). Then there  
is the time when real storage is short and you must put an active  
task to sleep so you can either swap of page out the task. I do not  
know a lot about how OS X and how I/O takes place on it. Can you  
chain say ten I/O's together or is it one page per page in/out per  
operation and here is the more interesting questions what size is  
each page is it 1K,4K,16K,32K,64K ?
Maximizing the decision to swap in/out and or page(s) in/out is  
really almost a mathematicians dream. At least one OS does this and  
more. But in any case since MAC does not externalize the information  
so we are guessing here.

Ed