prelink performance gains

[Simo Sorce]

On Tue, 2013-10-15 at 19:32 +0200, Jan Kratochvil wrote:
> On Tue, 15 Oct 2013 18:27:23 +0200, Dhiru Kholia wrote:
> > In spite of this fact, I believe that they are enough to demonstrate
> > that prelink is not resulting in any big gains anymore.
> 
> Nobody says prelink brings _big_ gains.  It is just a negligible performance
> and negligible battery optimization nowadays.
> 
> I just do not understand why to give up on that negligible optimization when
> it brings no disadvantages.

Prelink does big disadvantages, otherwise nobody would care.
One is about security, as it negates randomization of addresses,
modification of binaries in itself is pretty perverse to gain just
imperceptible performance gains. Many tools need to juggle the fact
these binaries have been changed, and make checkers more complex and
prone to faults.

In general prelink makes things more complex for negligible gains, its
worth is highly questionable.

> The disagreement here is whether it brings some disadvantages or not.

I just hope you are not saying that there is a doubt there are
disadvantages.

The real question here is whether advantages supersede disadvantges, and
given the only advantage seem to be performance and it is lost in noise,
I hardly see how the advantages are enough to justify using it these
days.

Simo.

-- 
Simo Sorce * Red Hat, Inc * New York