Performance enhancements

[Net Llama!]

On Mon, 30 Dec 2002, Marvin P. Dickens wrote:
> On Mon, 30 Dec 2002 13:44:09 -0500
> Tim Wunder <tim at thewunders.org> wrote:
>
> > But, what could possibly be *gained*, performance-wise, by turning swap off?
> > If swap isn't needed, it won't be used...
>
>
>
> Linux kernel code and data are not swappable and are never moved to
> swap.  User code never needs to be written to swap space because it
> already exists on disk and can be read in from there if it is required
> again. User data is the only data that is written to swap space. Once user
> data is in swap, it is read back in when it is needed. If your application
> is dependent on swap performance, you need more RAM.  This is where you
> gain performance. Swap should be viewed as a lightweight background
> optimization to make unused pages available for other work, rather
> than as a cure for an underprovisioned machine (Which is what swap
> has become). The point was and still is that memory is dirt cheap (For
> the price of a crappy usb webcam, you can purchase 256MB of RAM).

THis may all be well & true, however it still doesnt' address the fact
that disabling swap is not a performance enhancement, but rather a
performance degradation.

-- 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Lonni J Friedman				netllama at linux-sxs.org
Linux Step-by-step & TyGeMo		     http://netllama.ipfox.com