use MALLOC_PERTURB_ ... or lose

[Eric Sandeen]

On 05/05/2010 12:21 PM, David Malcolm wrote:
> On Wed, 2010-05-05 at 18:24 +0200, Michal Schmidt wrote:
>> On Wed, 05 May 2010 17:30:29 +0200 Jim Meyering wrote:
>>> I propose (seriously, now) to add this to /etc/profile,
>>> or to some always-sourced file like /etc/profile.d/glibc.sh:
>>>
>>>     # Enable glibc's malloc perturbing feature in Rawhide.
>>>     # http://udrepper.livejournal.com/11429.html
>>>     read _f _r _n _code_name < /etc/redhat-release &&
>>>     case $_code_name in
>>>         *Rawhide*) export MALLOC_PERTURB_=$((RANDOM % 255 + 1)) ;;
>>>     esac
>>
>> Would export MALLOC_CHECK_=3 be a useful addition too?
> 
> I like the idea of rawhide-only debug checks like this, but can we add
> some kind of message to login like this:

Agreed, I'm tired of (insert random benchmarking site) saying "OH NOES!
Fedora got SLOWER AGAIN!" when it's really a lot of debug going on.

Stating something like this clearly on login & install would be nice,
not just for this MALLOC_PERTURB_ change but in general.

-Eric

> <idea>
> This is a pre-release version of Fedora, and is running with extra
> diagnostics that help find bugs, but impact performance.
> 
> Please read
> (LINK TO A WIKI PAGE)
> before attempting to run benchmarks on this system.
> </idea>
> 
> Is there a good place to add this?  e.g. /etc/issue ?  I'm not sure of
> how to handle a conditional there.
> 
> Dave
> 
>