PIE on 64bit

[John Moser]

Meant to go to list
On Apr 18, 2013 2:15 PM, "John Moser" <john.r.moser at gmail.com> wrote:

>
> On Apr 18, 2013 2:07 PM, "Insanity Bit" <colintrexob at gmail.com> wrote:
> >
> > On 64bit multiple services (pulseaudio, rsyslogd, many others) are
> shipping without Position Independent Code. On 32bit there is a potential
> performance hit for startup time... but there shouldn't be any performance
> hit (or negligible) on 64bit.
> >
>
> There is a continuous performance hit of under 1% without
> -fomit-frame-pointer and under 6% with -fomit-frame-pointer on IA-32.  The
> impact is statistically insignificant (i got 0.002% +/- 0.5%) on x86-64.
>
> The performance hit on IA-32 only applies to main executable code because
> library code is PIC already.  This accounts for under 2% runtime, except in
> X where it used to be 5%.  That makes the overall impact 2% of 6% or
> 0.12%--which is non-existent if your CPU is ever at less than 99.88% load
> because you would swiftly catch up.
>
> In other words:  there is NO PERFORMANCE HIT for PIE in any
> non-laboratory, non-theoretical situation.  (Theo de Raadt argued this with
> me once, using the term "very expensive" a lot.  I built two identical
> Gentoo boxes and profiled them both extensively with oprofile.  It is
> exactly a theoretical cost, and the performance concerns come from people
> who have no clue what the execution flow of modern software looks like)
>
> > "PIE on x86_64 does not have the same penalties, and will eventually be
> made the default, but more testing is required."
> > - https://wiki.ubuntu.com/Security/Features#pie
> >
> > Is there an open bug for testing? A way for users to test and give
> feedback without recompiling massive projects like pulseaudio?
> >
> > 13.04 still doesn't ship PIE. I would expect this would be something
> you'd want to put in *before* an LTS release?
> >
> >
> > --
> > Ubuntu-devel-discuss mailing list
> > Ubuntu-devel-discuss at lists.ubuntu.com
> > Modify settings or unsubscribe at:
> https://lists.ubuntu.com/mailman/listinfo/ubuntu-devel-discuss
> >
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.ubuntu.com/archives/ubuntu-devel-discuss/attachments/20130418/0d8cf16b/attachment.html>