Re: Boot time: Kernel start parallelization issue?

[Dirk Behme <dirk.behme@googlemail.com>]

On 15.01.2011 16:41, Arjan van de Ven wrote:
> On 1/15/2011 12:40 AM, Dirk Behme wrote:
>>
>> There are some reports [1] [2] looking at the boot time of embedded
>> (ARM?) systems using initcall debug [3]. Both reports seem to show
>> that they have issues with the start up sequence of the kernel being
>> completely single-threaded. In [2] Greg mentions that on a x86 box
>> multi-threads are happening and that there he doesn't see this
>> issue. On the other hand, both reports mention Arjan's async
>> initcall patches [4] to help against the issue. I.e. introducing
>> some parallelization (on ARM) does help, too.
>>
>> With this, I wonder
>>
>> - if anybody faces similar issues with single-threaded only kernel
>> start on embedded (ARM?) systems? Or if this is known? Or if there
>> are fixes for this?
>>
>> - if we somehow should try to 're-activate' Arjan's async initcall
>> patches?
>
> those patches are obsoleted by the merged async_schedule() calls.

Any link (patch name, git link) to be able to check for 
async_schedule() calls?

> what kernel are you seeing issues on?

[1] talks about 2.6.28, [2] talks about 2.6.34.

Best regards

Dirk

[1] 
http://www.lindusembedded.com/blog/2010/06/02/measuring-the-boot-time-of-an-embedded-linux-device/

[2] http://thread.gmane.org/gmane.linux.usb.general/41181 (mainly the 
last mail of this thread: 
http://article.gmane.org/gmane.linux.usb.general/41619)