Significant performance problem with modprobe

[Ed W]

On 14/06/2011 11:31, Lauri Kasanen wrote:
>> For you, based on the bootchart, it looks like modprobe is actually
>> loading modules. and the time to do (a) is insignificant compared to (b)
>> and (c). It's probably taking most of time in (c) which means kernel is
>> working and initialising the module and possibly hardware. It's probably
>> non-trivial to try to improve your situation.
>>
>> - Timo
>>
> 
> According to strace, init_module is responsible for 85-95% of the time
> (depending on the module), but the rest is practically all from read.
> 
> While fixing this issue wouldn't make a huge difference in my case, it
> would seem to have a measurable effect nonetheless.
> I guess for the big effect I should wait for the mentioned module loader
> work.

A quick way to benchmark the difference would be to add a newish
module-init-tools binary to your system and measure the speed increase?
"proper" modprobe on my x86 system is 30KB

I don't doubt Timo, but obviously it helps if there are others who care
and might help investigate solutions to this?

Good luck

Ed W