Re: [systemd-devel] How to delete device units presented in systemd-analyze plot.

2013-09-11 Thread Lennart Poettering
On Mon, 12.08.13 01:44, Tony Seo (tonys...@gmail.com) wrote:

 I sincerely ask you a relationship between device unit and boot time if I
 remove unnecessary device unit.
 
 And also, can I ask you detail process of  making device unit by systemd?
 (I alread read the manual page related with device unit)

the kernel creates a directory in /sys for each device popping up. udev
then maintains some additional metadata for all those devices. One part
of that metadata is a tag that might be on select devices called
systemd. If a a device is tagged like that it will also show up as
.device unit systemd. By default block devices, ttys and a few others
are tagged like that. Some services need to wait for some block devices
before they can be run (for example, fsck instances need to wait for
their respective block devices to show up before they can be started),
and this is implemented via dependencies to these device units.

Device units hence are not really something active in themselves, they
just reflect as units state of another component of the OS (which is
udev/kernel).

Lennart

-- 
Lennart Poettering - Red Hat, Inc.
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Re: [systemd-devel] How to delete device units presented in systemd-analyze plot.

2013-08-11 Thread Tony Seo
Hi.

Today, I would want to share dramatic results through your good aids.



Could you visit my blog to check the results?

blog: http://best-dream-boy.blogspot.kr/

(subject: 2013.08.11 - Test1,  2013.08.11 - Test2)



If you visit to my blog, you can see test1 and test2 picture.

Those things were results from my test board.

Since the beginning of my test, I have erased many service units thought as
 unnecessary for working my board.

Yeah, I want to optimize systemd to work my board.

Finally, I got a result like test 2 picture.

As you see two pictures,  Different things are avplayer.unit and some
device units.

In those test,  I didn't use /etc/fstab in my systemd,

The only dissimilarity was the existence of avplayer unit, and some device
units came up.

I wonder why device unit was appeared in spite of erasing /etc/fstab.

I sincerely ask you a relationship between device unit and boot time if I
remove unnecessary device unit.

And also, can I ask you detail process of  making device unit by systemd?
(I alread read the manual page related with device unit)

Thanks.


Tony Seo.
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Re: [systemd-devel] How to delete device units presented in systemd-analyze plot.

2013-08-08 Thread Mantas Mikulėnas
On Thu, Aug 8, 2013 at 4:10 AM, Tony Seo tonys...@gmail.com wrote:

  I understand what you mean, but I think that I will cut the time for
 loading device unit if I keep those from appearing on my plot.

No, just hiding them will not change anything.

  What do think that loading time for device units doesn't affect to boot
 speed at machine?

It doesn't, because the units do not *exist*.

That's the part you keep misunderstanding. Device units by themselves
will not *make* systemd wait for a device. They exist only to *show*
that systemd *knows about* that device.

If you turn on the computer, and it takes several seconds for a device
like /sys/devices/platform/soc-audio/sound/card0 to appear, then it
*will* take several seconds for that device to appear, whether a
systemd shows it as a .device unit or not.






/sys/devices/platform/soc-audio/sound/card0
/sys/devices/platform/tcc-gmac/net/eth0
/sys/devices/platform/tcc-uart.0/tty/ttyTCC0
/sys/devices/platform/dwc_otg.0/gadget/tty/ttyGS0

...what kind of a device is it, anyway? A raspberryπ?

-- 
Mantas Mikulėnas graw...@gmail.com
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Re: [systemd-devel] How to delete device units presented in systemd-analyze plot.

2013-08-07 Thread Mantas Mikulėnas
On Wed, Aug 7, 2013 at 8:03 PM, Tony Seo tonys...@gmail.com wrote:

  Hello.

 Now, I have studied systemd for optimizing systemd on my board.

 After edited several units, I would like to delete some device configuration
 units existing on my picture from systemd-analyze(best-dream-boy.blogspot)

 I read the manual pages about systemd.device, I tried to delete device units
 through editing /etc/fstab and systemctl mask.

 But I couldn't delete those device units, at least existing units on the
 picture.

You cannot delete these units because they do not exist anywhere
except in memory – they're only a way to represent device status in
the format of systemd units. In other words, they do not cause the
problems you're having; they only make the problems visible in your
bootchart.

-- 
Mantas Mikulėnas graw...@gmail.com
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Re: [systemd-devel] How to delete device units presented in systemd-analyze plot.

2013-08-07 Thread Tony Seo
 I understand what you mean, but I think that I will cut the time for
loading device unit if I keep those from appearing on my plot.

 I want to do a try to temporarily disappear some kinds of device units and
then I'm supposed to measure boot speed depending a board of
mine.(Actually, I believe that loading time for device unit affects to boot
speed)

 What do think that loading time for device units doesn't affect to boot
speed at machine?

 Thanks.



2013/8/8 Mantas Mikulėnas graw...@gmail.com

 On Wed, Aug 7, 2013 at 8:03 PM, Tony Seo tonys...@gmail.com wrote:
 
   Hello.
 
  Now, I have studied systemd for optimizing systemd on my board.
 
  After edited several units, I would like to delete some device
 configuration
  units existing on my picture from
 systemd-analyze(best-dream-boy.blogspot)
 
  I read the manual pages about systemd.device, I tried to delete device
 units
  through editing /etc/fstab and systemctl mask.
 
  But I couldn't delete those device units, at least existing units on the
  picture.

 You cannot delete these units because they do not exist anywhere
 except in memory – they're only a way to represent device status in
 the format of systemd units. In other words, they do not cause the
 problems you're having; they only make the problems visible in your
 bootchart.

 --
 Mantas Mikulėnas graw...@gmail.com

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Re: [systemd-devel] How to delete device units presented in systemd-analyze plot.

2013-08-07 Thread Hoyer, Marko (ADITG/SW2)
Hi Tony,

best to my experiences, I doubt that suppressing the loading of device units 
will speed up systemd that much. There are other major parts that far more 
significantly delay the startup (cgroups in some cases, loading the unit set at 
startup, executing the generators, and finally loading the binary of systemd 
and the shared libraries ...). You'll probably gain more benefit when starting 
to optimize at these ends ...

Best regards

Marko Hoyer
Software Group II (ADITG/SW2)


Best regards

Marko Hoyer
Software Group II (ADITG/SW2)

Tel. +49 5121 49 6948

 -Original Message-
 From: systemd-devel-bounces+mhoyer=de.adit-jv@lists.freedesktop.org
 [mailto:systemd-devel-bounces+mhoyer=de.adit-jv@lists.freedesktop.org] On
 Behalf Of Tony Seo
 Sent: Thursday, August 08, 2013 3:12 AM
 To: Mantas Mikulėnas
 Cc: systemd-devel@lists.freedesktop.org
 Subject: Re: [systemd-devel] How to delete device units presented in systemd-
 analyze plot.
 
 
  I understand what you mean, but I think that I will cut the time for loading
 device unit if I keep those from appearing on my plot.
 
  I want to do a try to temporarily disappear some kinds of device units and
 then I'm supposed to measure boot speed depending a board of mine.(Actually, I
 believe that loading time for device unit affects to boot speed)
 
  What do think that loading time for device units doesn't affect to boot speed
 at machine?
 
  Thanks.
 
 
 
 2013/8/8 Mantas Mikulėnas graw...@gmail.com
 
 
   On Wed, Aug 7, 2013 at 8:03 PM, Tony Seo tonys...@gmail.com wrote:
   
 Hello.
   
Now, I have studied systemd for optimizing systemd on my board.
   
After edited several units, I would like to delete some device
 configuration
units existing on my picture from systemd-analyze(best-dream-
 boy.blogspot)
   
I read the manual pages about systemd.device, I tried to delete
 device units
through editing /etc/fstab and systemctl mask.
   
But I couldn't delete those device units, at least existing units on
 the
picture.
 
 
   You cannot delete these units because they do not exist anywhere
   except in memory – they're only a way to represent device status in
   the format of systemd units. In other words, they do not cause the
   problems you're having; they only make the problems visible in your
   bootchart.
 
   --
   Mantas Mikulėnas graw...@gmail.com
 
 

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