Re: Prelink problems -- need help!

[Mark Hatle <mark.hatle@windriver.com>]

On 10/26/15 11:50 AM, Phil Blundell wrote:
> On Mon, 2015-10-26 at 11:45 -0500, Mark Hatle wrote:
>>
>>
>> While some of the modern hashing techniques and such do improve run
>> -time dynamic
>> link performance, there is still a hit that we must take.  For
>> devices that need
>> quick boot times, quick startup, or are memory constrained, the
>> prelinker can
>> still help.  (Memory usage on very small systems is a good example. 
>>  Memory
>> usage can be reduced in larger applications by reducing the number of
>> Copy-on-write pages required to handle the relocation information.)
> 
> Do you have any concrete data on how much of a boot time speedup,
> and/or what reduction in dirty pages, you see on a modern image with
> prelink versus the same image without?

-last- time I got concrete numbers on a complex boot process.  It was on the
order of 1-5% boot time.. and a fairly large number of pages saved.. (which
reduced fragmentation as well as saved memory.)

We're not talking huge numbers for each, there is a statistics mode in glibc
that can be enabled to show the number of relocations and some of the costs
involved.  Once this is working again, I will be able to run that and give more
concrete numbers.

--Mark

> p.
>