[X4U] how to view "pageouts?"

[Ed Gould]

On Jun 17, 2008, at 8:24 PM, Linda wrote:

> On 6/17/08 6:11 PM, zapcat wrote:
>
>> anyone familiar with pageouts (with respect to RAM...not enough
>> RAM...etc)
>>
>> can pageout activity be useful as a diagnostic tool, to help gauge
>> performance and load on a Mac, or does it basically just remind me  
>> that
>> the machine doesn't have enough RAM?
>
> I use MenuMeters to show me my pageouts. I'm having fewer than I  
> thought I
> was -- my RAM is barely all ever used, wired, or active at once.  
> So, it's
> useful in that I am looking for other reasons that my Mac bogs  
> down, rather
> than assuming it's a lack of RAM.
>
> ~Linda
>
>

Linda,

Let me take a stab at the question. As always it depends.
The short answer is "maybe"
The long answer is quite involved and it goes into vary complicated  
mathematics.
It also depends on the machines OS (and maybe which version) and how  
it decides what to page and how the operating system is programmed to  
page (in or out) it also depends on how fast the disk drive is that  
is doing the paging. There are a few more "dependings" . There are  
quite a few books on paging and you probably have to have more than a  
nodding acquaintance to at least college level math.

I know this sounds like a song and dance but it really isn't it  
depends on a *quite a few* of side factors. IOW it is difficult to  
give a straight forward answer to your question. It is different  
depending on quite a few factors.

Not a hard rule but...

Page outs tend to hurt a little, page ins tend to hurt a lot
If you need a page that has just been paged out the system can be  
sluggish (it depends on which page(s) ) have been paged out.
I do not know of any MAC tools (there may be some out there but I  
somehow doubt it) that will give you reams of reports. I know one  
manufacture that has a tool but it does not run on a MAC.
The output of those types of reports are almost endlessly analyzed  
and scrutinized by thousands of math types every day and these types  
are high paid tech types.

If you must have a golden rule page ins or page outs are almost  
always going to happen. Its when it "hurts" you that is when you have  
to make a decision as to buying more memory. 64G is probably the most  
you can have on a typical MAC. Memory is cheap right now and I would  
recommend getting as much as you can afford. Its the "cheapest" way  
of speeding up your system
BUT until you have issues with response time you may not need any.

I hope I wasn't to complicated in my response.

Ed