# Very bad performance with recent kernels

## ToeiRei

Hi guys,

I am facing the problem, that my laptop performance gets worse every new kernel version. Recently I discovered ksoftirqd (8 processes!) hogging up most of the CPU.

The box is a Lenovo Thinkpad W530

```
freya ~ # lspci

00:00.0 Host bridge: Intel Corporation 3rd Gen Core processor DRAM Controller (rev 09)

00:01.0 PCI bridge: Intel Corporation Xeon E3-1200 v2/3rd Gen Core processor PCI Express Root Port (rev 09)

00:02.0 VGA compatible controller: Intel Corporation 3rd Gen Core processor Graphics Controller (rev 09)

00:14.0 USB controller: Intel Corporation 7 Series/C210 Series Chipset Family USB xHCI Host Controller (rev 04)

00:16.0 Communication controller: Intel Corporation 7 Series/C210 Series Chipset Family MEI Controller #1 (rev 04)

00:19.0 Ethernet controller: Intel Corporation 82579LM Gigabit Network Connection (rev 04)

00:1a.0 USB controller: Intel Corporation 7 Series/C210 Series Chipset Family USB Enhanced Host Controller #2 (rev 04)

00:1b.0 Audio device: Intel Corporation 7 Series/C210 Series Chipset Family High Definition Audio Controller (rev 04)

00:1c.0 PCI bridge: Intel Corporation 7 Series/C210 Series Chipset Family PCI Express Root Port 1 (rev c4)

00:1c.1 PCI bridge: Intel Corporation 7 Series/C210 Series Chipset Family PCI Express Root Port 2 (rev c4)

00:1c.2 PCI bridge: Intel Corporation 7 Series/C210 Series Chipset Family PCI Express Root Port 3 (rev c4)

00:1d.0 USB controller: Intel Corporation 7 Series/C210 Series Chipset Family USB Enhanced Host Controller #1 (rev 04)

00:1f.0 ISA bridge: Intel Corporation QM77 Express Chipset LPC Controller (rev 04)

00:1f.2 SATA controller: Intel Corporation 7 Series Chipset Family 6-port SATA Controller [AHCI mode] (rev 04)

00:1f.3 SMBus: Intel Corporation 7 Series/C210 Series Chipset Family SMBus Controller (rev 04)

01:00.0 VGA compatible controller: NVIDIA Corporation GK107GLM [Quadro K2000M] (rev a1)

02:00.0 System peripheral: Ricoh Co Ltd MMC/SD Host Controller (rev 08)

02:00.3 FireWire (IEEE 1394): Ricoh Co Ltd R5C832 PCIe IEEE 1394 Controller (rev 04)

03:00.0 Network controller: Intel Corporation Centrino Ultimate-N 6300 (rev 3e)

freya ~ # 
```

Kernel Config: http://bpaste.net/show/117296/

any ideas?

regards

Rei

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## DONAHUE

http://askubuntu.com/questions/7858/why-is-ksoftirqd-0-process-using-all-my-cpu

discussion

https://www.centos.org/modules/newbb/viewtopic.php?topic_id=39308 says following fixes:

I did find out how to fix this. In the kernel command line (/etc/grub.conf), add "nohz=off"

my kernel which is sourced from pappy's kernel seeds has  *Quote:*   

> #
> 
> # Timers subsystem
> 
> #
> ...

  which appears to be another way to do the same thing. I have no independent knowledge of timers subsystem.

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## DONAHUE

dupe

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## ToeiRei

this is pretty weird. Looks like the tickless system is an issue

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## handsoul

for kernel version >= 3.10, Set the option as following  might help.

```
General setup >

  Timers subsystem->

    Timer tick handling (Idle dynticks system (tickless idle)) ->

        ( ) Periodic timer ticks (constant rate, no dynticks)       

        (X) Idle dynticks system (tickless idle) 

        ( ) Full dynticks system (tickless)

```

if  you choose "Full dynticks system"  here , wired things might happen: all cores  keep runing at the full frequence , and cpu frequence scaling settings do not have any effect. I've no idea about this. The problem's seen on i3-2330M.

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## platojones

 *ToeiRei wrote:*   

> this is pretty weird. Looks like the tickless system is an issue

 

According to Linus, full-tickless is not quite ready for prime time...it's evolving, but not there yet:

http://lwn.net/Articles/549580/

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