Re: [systemd-devel] systemd-cgtop doesn't show Input/Output

[Barry Scott]

> On 6 Dec 2022, at 06:45, Vladimir Mokrozub  wrote:
> 
> Thank you, I added "systemd.unified_cgroup_hierarchy=1 " to the kernel's 
> command line and systemd-cgtop now shows Input/Output.
> However, I ran into a problem with LXC containers after switching to unified 
> mode and though I managed to solve it, I'm worried that something else might 
> break in the future.
> Is it safe to switch to v2 mode?

Better question is this; Is it safe to stay on the legacy V1 with its missing 
features and no new development?

At some point you will have to fix the issues if you depend on legacy v1 
cgroups.
The v1 support is being dropped from systemd at some point I think.

Barry

> 
> 
> 
> On Mon, Dec 5, 2022 at 4:16 PM Michal Koutný  > wrote:
>> Hello.
>> 
>> On Mon, Dec 05, 2022 at 09:38:18AM +0300, Vladimir Mokrozub 
>> mailto:mogaba2...@gmail.com>> wrote:
>> > $ systemctl --version
>> > systemd 245 (245.4-4ubuntu3.19)
>> > +PAM +AUDIT +SELINUX +IMA +APPARMOR +SMACK +SYSVINIT +UTMP +LIBCRYPTSETUP
>> > +GCRYPT +GNUTLS +ACL +XZ +LZ4 +SECCOMP +BLKID +ELFUTILS +KMOD +IDN2 -IDN
>> > +PCRE2 default-hierarchy=hybrid
>>^^
>> Unless you override this on kernel cmdline, it means (blk)io controller
>> is in v1 mode.
>> 
>> > systemd-cgtop always has "-" in both Input/s and Output/s columns. There
>> > are no spikes, even under a high disk load.
>> > I was testing it with "dd if=/dev/sda of=/dev/null". Here's the output:
>> > 
>> > Control GroupTasks   %CPU   Memory  Input/s Output/s
>> > /  214 101.5   3.7G   --
>> > user.slice   15   99.6   2.9G   --
>> > system.slice  97 0.4 95.4M   --
>> 
>> 1) It won't have proper hierarchical behavior (thus no values for .slice
>>units, cgtop defaults to depth of 3 thus you may not see the active
>>leaves),
>> 2) it won't charge writeback IO properly (just FYI, it's not relevant
>>to your example).
>> 
>> If you can, I'd suggest you to switch to the unified mode if you want
>> hierarchical IO accounting.
>> 
>> HTH,
>> Michal

Re: [systemd-devel] systemd-cgtop doesn't show Input/Output

[Vladimir Mokrozub]

Thank you, I added "systemd.unified_cgroup_hierarchy=1 " to the kernel's
command line and systemd-cgtop now shows Input/Output.
However, I ran into a problem with LXC containers after switching to
unified mode and though I managed to solve it, I'm worried that something
else might break in the future.
Is it safe to switch to v2 mode?



On Mon, Dec 5, 2022 at 4:16 PM Michal Koutný  wrote:

> Hello.
>
> On Mon, Dec 05, 2022 at 09:38:18AM +0300, Vladimir Mokrozub <
> mogaba2...@gmail.com> wrote:
> > $ systemctl --version
> > systemd 245 (245.4-4ubuntu3.19)
> > +PAM +AUDIT +SELINUX +IMA +APPARMOR +SMACK +SYSVINIT +UTMP +LIBCRYPTSETUP
> > +GCRYPT +GNUTLS +ACL +XZ +LZ4 +SECCOMP +BLKID +ELFUTILS +KMOD +IDN2 -IDN
> > +PCRE2 default-hierarchy=hybrid
>^^
> Unless you override this on kernel cmdline, it means (blk)io controller
> is in v1 mode.
>
> > systemd-cgtop always has "-" in both Input/s and Output/s columns. There
> > are no spikes, even under a high disk load.
> > I was testing it with "dd if=/dev/sda of=/dev/null". Here's the output:
> >
> > Control GroupTasks   %CPU   Memory  Input/s Output/s
> > /  214 101.5   3.7G   --
> > user.slice   15   99.6   2.9G   --
> > system.slice  97 0.4 95.4M   --
>
> 1) It won't have proper hierarchical behavior (thus no values for .slice
>units, cgtop defaults to depth of 3 thus you may not see the active
>leaves),
> 2) it won't charge writeback IO properly (just FYI, it's not relevant
>to your example).
>
> If you can, I'd suggest you to switch to the unified mode if you want
> hierarchical IO accounting.
>
> HTH,
> Michal
>

Re: [systemd-devel] systemd-cgtop doesn't show Input/Output

[Michal Koutný]

Hello.

On Mon, Dec 05, 2022 at 09:38:18AM +0300, Vladimir Mokrozub 
 wrote:
> $ systemctl --version
> systemd 245 (245.4-4ubuntu3.19)
> +PAM +AUDIT +SELINUX +IMA +APPARMOR +SMACK +SYSVINIT +UTMP +LIBCRYPTSETUP
> +GCRYPT +GNUTLS +ACL +XZ +LZ4 +SECCOMP +BLKID +ELFUTILS +KMOD +IDN2 -IDN
> +PCRE2 default-hierarchy=hybrid
   ^^
Unless you override this on kernel cmdline, it means (blk)io controller
is in v1 mode.

> systemd-cgtop always has "-" in both Input/s and Output/s columns. There
> are no spikes, even under a high disk load.
> I was testing it with "dd if=/dev/sda of=/dev/null". Here's the output:
> 
> Control GroupTasks   %CPU   Memory  Input/s Output/s
> /  214 101.5   3.7G   --
> user.slice   15   99.6   2.9G   --
> system.slice  97 0.4 95.4M   --

1) It won't have proper hierarchical behavior (thus no values for .slice
   units, cgtop defaults to depth of 3 thus you may not see the active
   leaves),
2) it won't charge writeback IO properly (just FYI, it's not relevant
   to your example).

If you can, I'd suggest you to switch to the unified mode if you want
hierarchical IO accounting.

HTH,
Michal


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[systemd-devel] systemd-cgtop doesn't show Input/Output

[Vladimir Mokrozub]

 OS: Ubuntu 20.04

$ systemctl --version
systemd 245 (245.4-4ubuntu3.19)
+PAM +AUDIT +SELINUX +IMA +APPARMOR +SMACK +SYSVINIT +UTMP +LIBCRYPTSETUP
+GCRYPT +GNUTLS +ACL +XZ +LZ4 +SECCOMP +BLKID +ELFUTILS +KMOD +IDN2 -IDN
+PCRE2 default-hierarchy=hybrid

systemd-cgtop always has "-" in both Input/s and Output/s columns. There
are no spikes, even under a high disk load.
I was testing it with "dd if=/dev/sda of=/dev/null". Here's the output:

Control GroupTasks   %CPU   Memory  Input/s Output/s
/  214 101.5   3.7G   --
user.slice   15   99.6   2.9G   --
system.slice  97 0.4 95.4M   --

I tried the following settings in /etc/systemd/system.conf:
DefaultIOAccounting=yes
DefaultBlockIOAccounting=yes

But it didn't help.
Any help would be appreciated.

--
Vladimir Mokrozub