[fedora-arm] Include prelink in fedora arm?

[William Cohen]

On 09/07/2011 01:48 AM, Martin Dengler wrote:
> On Tue, Sep 06, 2011 at 07:54:17PM +0100, Gordan Bobic wrote:
>> On 09/06/2011 06:53 PM, Mark Wielaard wrote:
>>> On Tue, Sep 06, 2011 at 07:22:37PM +0200, Jan Kratochvil wrote:
>>>> On Tue, 06 Sep 2011 19:15:45 +0200, Kevin Fenzi wrote:
>>>>> Personally, I would consider prelink a 'ok, we have everything working
>>>>> now, and we want to look at making it faster' instead of enabling it
>>>>> before everything is working or building.
>>>>
>>>> I agree That makes sense (although I do not think the prelink issues will be
>>>> ARM specific and they are already resolved on other arches; I may be wrong).
>>>
>>> There could be ARM specific bugs. [...]  having the prelink
>>> package available on ARM would at least help us all test and make
>>> sure prelink works as intended. So please do include the package,
>>> if only so people can do some measurements to check whether the
>>> startup speedup is "just" 10% or even up to 50% on their machines.
>>
>> I agree on the dependency and testing part, but I think 10% is
>> optimistic.
> 
> I will soon have a few different ARM machines that I can do testing
> on.  Please let us know[1] your test suite if you want me to try to
> substantiate your pessimism.
> 
> Here is the best reason I've heard for prelink on today's standard,
> memory-constrained ARM device:
> 
> http://lists.laptop.org/pipermail/devel/2011-May/032011.html
> 
> Please keep at least the option to enable prelinking in Fedora,
> especially before anyone has any performance numbers.
> 
>> Gordan
> 
> Martin
> 
> 1. A wiki page about prelink on ARM would probably be even better than
> a mailing list post.  I will start one if nobody beats me to it.

I ran a little experiment with and without prelink using ps_mem.py from
http://www.pixelbeat.org/scripts/ps_mem.py

I booted up the fc13 arm machine and logged in with two terminal windows up and ran ps_mem.py saving the result into a file. The no_prelink_mem.log is the output without prelink and prelink_mem.log is the output after a prelink and reboot.  Savings is about 2.7% (107.6MB vs 110.6MB) of the RAM in this trivial case.  Generally, see the amount of private memory required for individual executables reduced for the prelinked versions. There were a some that had higher private memory use (bluetoothd, dbus-daemon, and udevd), but that might be more of a result of the quick and dirty benchmarking.

-Will

-Will
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