[systemd-devel] [PATCH] core: add default extra dependency option

[WaLyong Cho]

On 03/03/2014 11:43 PM, Lennart Poettering wrote:
> On Mon, 03.03.14 11:52, WaLyong Cho (walyong.cho at samsung.com) wrote:
> 
>>> But if you do this on an embedded system you can do
>>> DefaultDependencies=no for all services where you want this and place
>>> them manually?
>>>
>> Almost I can. Actually I can request to the package manager in our
>> system. But, I don't want to put DefaultDependencies=no to all of
>> services. Then all of services should consider which mount, socket, path
>> and more units are needed to launch itself. I don't want this. I just
>> wants they launch after basic.target and some of special services what
>> should be per-processed before than others to optimize boot speed
>> extremely. (Those pre-processed services will be listed in config with
>> DefaultExtraDependencies=)
>>>
>>> Also, are you sure that you really want to solve this with manual deps?
>>> I mean, the kernel already has a CPU scheduler and an IO
>>> scheduler. Maybe it would be better to simply dump all the scheduling
>>> work on the kernel as far as that is possible, start everything in
>>> parallel, but then also tell the kernel what matters more, and what
>>> matters less.
>>>
>>> We already expose CPUShares= and BlockIOWeight= for services. Maybe we
>>> should duplicate these as StartupCPUShares= and StartupBlockIOWeight=
>>> which could set different values to apply only while the boot process is
>>> not complete yet. Or something like that. 
>>>
>>> Lennart
>>>
>> Parallel is good and by this, systemd is very flexible to suit our
>> product. But I(our product) want to some of services occupy most of
>> system resources at the head of boot sequence. (don't confuse that will
>> after basic.target) Some more detail, we play some of animation during
>> boot and we call that boot-animation(similar with splash animation).
>> During that time, we launch essential services and idle screen with this
>> functionality. At this time, we don't want any other services are using
>> system resources.
>>
>> StartupCPUShares= and StartupBlockIOWeight= maybe good idea. But should
>> be considered it really OK, lower or higher CPUShares and BlockIOWeight
>> during whole boot time.
> 
> Yes, precisely, that is what I want StartupCPUShares= to be: an
> alternative to CPUShares= that is applied only while the system is
> booting up.
> 
> A service with this configuration:
> 
>     CPUShares=1024
>     StartupCPUShares=10
> 
> Would be scheduled at a very low priority during startup, but as soon as
> startup is complete would be bumped to normal levels.
> 
> Lennart
> 

I sent new patch with new subject "core: add startup resource control
option".

Thank you,
WaLyong