Re: [PATCH 1/2] udevd: respect the value of TIMEOUT in uevents

[Alan Jenkins <alan-jenkins@tuffmail.co.uk>]

Kay Sievers wrote:
> On Tue, May 26, 2009 at 12:19, Alan Jenkins <alan-jenkins@tuffmail.co.uk> wrote:
>
>   
>> Don't apply patch 2 then :-).
>>     
>
> No worry, we can not be that fast here. :) We need to get numbers first.
>
> Threads don't come for free, they make udev much less reliable and
> harder to debug, compared to the current model. When all events share
> the same address space, and the memory for the events gets reused for
> forever, a simple bug will likely bring down the entire service,
> unlike today where an event process may crash, but the event
> management daemon will survive. Actually, I don't remember that the
> main udev ever crashed, and that will definitely change with the
> threads. :)
>
> I'm not against a threaded udevd, but we should have a good reason to
> do it that way. We also need to get numbers on bigger boxes. Udev runs
> on boxes with many thousands of events at bootup. we've seen boxes
> with 20.000+ disks, where every disk has ~10 devices in sysfs. Some of
> the SUSE customers requested to be able to run 4000+ events in
> parallel, to bring the bootup time on such boxes down to a reasonable
> time. That all works fine with today's udev and we need to be really
> careful here.
>
> Thanks,
> Kay
>   

Noted and agreed.  I'll work towards a complete series which can be
tested and reviewed as a whole.

Thanks
Alan