You are not logged in.

#1 2017-05-24 02:59:47

tpfkanep
Member
From: South Africa
Registered: 2009-12-15
Posts: 121

iotop reports that ksoftirqd uses 99.99 % IO

kernel: 4.11.2-1-ARCH

After bootup, iotop reports:

Total DISK READ :       0.00 B/s | Total DISK WRITE :       0.00 B/s
Actual DISK READ:       0.00 B/s | Actual DISK WRITE:       0.00 B/s
  TID  PRIO  USER     DISK READ  DISK WRITE  SWAPIN     IO>    COMMAND                            
    7 be/4 root          0.00 B      0.00 B  0.00 % 99.99 % [ksoftirqd/0]
   17 be/4 root          0.00 B      0.00 B  0.00 % 99.99 % [ksoftirqd/1]

After starting Xfce4, I normally get something similar to this:

Total DISK READ :       0.00 B/s | Total DISK WRITE :       0.00 B/s
Actual DISK READ:       0.00 B/s | Actual DISK WRITE:       0.00 B/s
  TID  PRIO  USER     DISK READ  DISK WRITE  SWAPIN     IO>    COMMAND                            
    7 be/4 root          0.00 B      0.00 B  0.00 % 99.99 % [ksoftirqd/0]
   17 be/4 root          0.00 B      0.00 B  0.00 % 99.99 % [ksoftirqd/1]
12836 be/4 tpfkanep      0.00 B      0.00 B  0.00 % 99.99 % opera --start-maxi~d [Chrome_IOThread]
12991 be/4 root          0.00 B      0.00 B  0.00 % 99.99 % python /usr/bin/iotop -ao
12935 be/4 tpfkanep      0.00 B      0.00 B  0.00 % 99.99 % opera --type=rende~1 [Chrome_ChildIOT]
11587 be/4 tpfkanep      0.00 B      0.00 B  0.00 % 99.99 % at-spi2-registryd --use-gnome-session
12807 be/4 tpfkanep      0.00 B     40.00 K  0.00 % 99.99 % firefox
12841 be/4 tpfkanep      0.00 B      0.00 B  0.00 % 99.99 % firefox [Timer]
12868 be/4 tpfkanep      0.00 B      8.00 K  0.00 % 99.99 % opera --start-maxi~d [BrowserBlocking]
12822 be/4 tpfkanep      0.00 B      0.00 B  0.00 % 99.99 % opera --start-maxi~ed [inotify_reader]

I use the deadline scheduler:

CONFIG_IOSCHED_DEADLINE=y
CONFIG_DEFAULT_DEADLINE=y
CONFIG_DEFAULT_IOSCHED="deadline"
CONFIG_MQ_IOSCHED_DEADLINE=y

noop and cfq also shows the same iotop results. The same behaviour is seen in zen and ck kernels.

top & htop does not show any unusual behaviour (ksoftirqd = 0% CPU) and no noticeable slowdowns in UI/commandline

4.10.13-1 does not have this behavior. What could be causing this?

Offline

#2 2017-05-24 06:22:45

seth
Member
Registered: 2012-09-03
Posts: 50,012

Re: iotop reports that ksoftirqd uses 99.99 % IO

Look at the numbers - there's no disk activity but apparently every process is on 99.9% I/O - looks like a misinterpretation/calculation by that script => are actually *all* processes on 99.9%

Offline

#3 2017-05-26 20:44:31

tpfkanep
Member
From: South Africa
Registered: 2009-12-15
Posts: 121

Re: iotop reports that ksoftirqd uses 99.99 % IO

Yeah it looks like all processes are reaching 99.99% over a period of time.

It normally starts with [ksoftirqd/0] and [ksoftirqd/1] at 99.9%. Then stuff like wvdial, xfwm, opera, [jfscommit], etc. all gradually go up to 99.9%. I first thought it was my custom kernels, but I just reinstalled the extra/linux-zen kernel from the repositories, but it exhibits the same behaviour as my custom zen kernel.

Is anyone else experiencing this...?

Offline

#4 2017-05-31 09:24:54

tpfkanep
Member
From: South Africa
Registered: 2009-12-15
Posts: 121

Re: iotop reports that ksoftirqd uses 99.99 % IO

Been a week waiting on an email response from the developer of iotop...

I have resorted to running iotop without the --accumulated option, instead using iotop -o. It does not solve the reporting of 99.99% IO for the threads/processes (ksoftirqd, etc.) that does IO.

Offline

#5 2018-03-22 12:03:38

xuancong
Member
Registered: 2018-03-22
Posts: 1

Re: iotop reports that ksoftirqd uses 99.99 % IO

There is some minor bugs with Linux Kernel 4.11 and onwards.
The CPU frequency control does not work either.

Offline

#6 2018-03-22 13:36:42

V1del
Forum Moderator
Registered: 2012-10-16
Posts: 21,429

Re: iotop reports that ksoftirqd uses 99.99 % IO

That doesn't really add much to the thread and it is unclear if what you are saying is related to the thread or a general observation that might or might not be true. If you have an actual issue you'd like to discuss, please open a new thread about it.

https://wiki.archlinux.org/index.php/Co … bumping.22

Closing.

Online

Board footer

Powered by FluxBB