Re: [gentoo-dev] Stack smash protected daemons

[Ciaran McCreesh]

On Wed, 22 Sep 2004 21:40:39 -0400 John Richard Moser
<nigelenki@×××××××.net> wrote:
| | Personally, I would be *very* wary about giving our x86 users a 5%
| | performance hit
| 
| 1.  Where are you getting 5% from?

I did some quick measurements on vim's test suite with and without
-fstack-protector. The value varies per app, of course, but vim's regex
stuff was taking a ~10% hit (not surprising) and the file ops were
affected considerably less. *shrug* depends upon the app, of course.

| 2.  What context is this "Performance" hit in?  gcc would take a
| "performance" hit because it eats 100% CPU; most nothing else would
| take a "performance" hit unless the *overhead* pulled CPU usage up to
| 100% for a time.

Well, performance when a box is at low load is of no interest...

| I guess this is the point where I have to ebuild unpack nbyte and
| generate SSP benchmarks.  Why oh why didn't I bench ssp when I was
| doing PIC?

Note that some kinds of benchmarks, such as integer op tests, won't
be affected at all by SSP. Certain kinds of string handling, on the
other hand, will be hit really badly. Better to pick an app and
benchmark it than running dedicated benchmarkers.

-- 
Ciaran McCreesh : Gentoo Developer (Sparc, MIPS, Vim, Fluxbox)
Mail            : ciaranm at gentoo.org
Web             : http://dev.gentoo.org/~ciaranm