Hello All,

A simple test app allocates and releases memory in an endless loop.
'top' shows that application acquires memory, but never releases it.
It looks like certain amount of memory is reserved by the
application.

How should 'top' memory readings be interpreted?

Thanks,
Alona

On Mon, 12 May 2008 09:28:27 -0700, Alona wrote:

> A simple test app allocates and releases memory in an endless loop.
> 'top' shows that application acquires memory, but never releases it. It
> looks like certain amount of memory is reserved by the application.

What does 'prstat -a' tell you about memory usage?

> How should 'top' memory readings be interpreted?

With toilet paper.

Alona wrote:
> Hello All,
>
> A simple test app allocates and releases memory in an endless loop.
> 'top' shows that application acquires memory, but never releases it.
> It looks like certain amount of memory is reserved by the
> application.
>
> How should 'top' memory readings be interpreted?
>
> Thanks,
> Alona

The numbers are probably correct. Most dynamic memory is taken
from the heap, and a certain amount of that is reserved by
the app when it starts. When an app requests memory, if there
isn't enough in the heap the malloc (or whatever) library
will request more from the OS, growing the heap.

When the app "free"s memory, it is restored to the heap but
not back to the OS pool. So when your app requests memory
you may see the amount of used memory increase in the top
output. When your app frees memory, it still is held by
the app, and top doesn't see the memory use decrease.

-Wayne