[Xenomai] Real-time Performance Improvement

[Xenomai] Real-time Performance Improvement

[Jack Lee]

Hi, everyone,

My board is advantech MIO-5251 (J1900 version), linux kernel version is 
4.1.18,

xenomai version is 3.0.3. As mentioned before, the real-time performance 
I got was

not good.

But I found something here: 
http://rtt-lwr.readthedocs.io/en/latest/rtpc/xenomai.html.

After "i915.enable_rc6=0 i915.modset=1 noapic" was added to the kernel 
command

line, the real-time performance improved a lot, which means latency 
tests (-t0, t1, t2)

has no overruns (less than 80us) in 13+ hours, but when other real-time 
applications

was running, overruns occurred sometimes.

I found that "intel_powerclamp" "intel_rapl" was in the "lsmod" list. 
After I removed them,

real-time performance of the system is quite good now.

I found configs below exist in the original .config file, except 
"CONFIG_CPU_THERMAL". These

configs do not appear on the official website as far as I know. Is it 
necessary to disable them to

improve real-time performance?

Generic Thermal sysfs driver
CONFIG_THERMAL

Fair-share thermal governor
CONFIG_THERMAL_GOV_FAIR_SHARE

Step_wise thermal governor
CONFIG_THERMAL_GOV_STEP_WISE

User_space thermal governor
CONFIG_THERMAL_GOV_USER_SPACE

generic cpu cooling support
CONFIG_CPU_THERMAL(n)

Thermal emulation mode support
CONFIG_THERMAL_EMULATION

Intel PowerClamp idle injection driver
CONFIG_INTEL_POWERCLAMP

By the way, I found my two Ethernet cards and the can board have the 
same interrupt number.I removed the igb module.

Is it possible to assign interrupt numbers manuallly? When I started 
from different kernels, the number is not the same.


Good luck!

[Xenomai] Real-time Performance Improvement

[Jack Lee]

On 09/22/2016 02:43 PM, Jack Lee wrote:
> Hi, everyone,
>
> My board is advantech MIO-5251 (J1900 version), linux kernel version 
> is 4.1.18,
>
> xenomai version is 3.0.3. As mentioned before, the real-time 
> performance I got was
>
> not good.
>
> But I found something here: 
> http://rtt-lwr.readthedocs.io/en/latest/rtpc/xenomai.html.
>
> After "i915.enable_rc6=0 i915.modset=1 noapic" was added to the kernel 
> command
>
> line, the real-time performance improved a lot, which means latency 
> tests (-t0, t1, t2)
>
> has no overruns (less than 80us) in 13+ hours, but when other 
> real-time applications
>
> was running, overruns occurred sometimes.
>
> I found that "intel_powerclamp" "intel_rapl" was in the "lsmod" list. 
> After I removed them,
>
> real-time performance of the system is quite good now.
>
> I found configs below exist in the original .config file, except 
> "CONFIG_CPU_THERMAL". These
>
> configs do not appear on the official website as far as I know. Is it 
> necessary to disable them to
>
> improve real-time performance?
>
> Generic Thermal sysfs driver
> CONFIG_THERMAL
>
> Fair-share thermal governor
> CONFIG_THERMAL_GOV_FAIR_SHARE
>
> Step_wise thermal governor
> CONFIG_THERMAL_GOV_STEP_WISE
>
> User_space thermal governor
> CONFIG_THERMAL_GOV_USER_SPACE
>
> generic cpu cooling support
> CONFIG_CPU_THERMAL(n)
>
> Thermal emulation mode support
> CONFIG_THERMAL_EMULATION
>
> Intel PowerClamp idle injection driver
> CONFIG_INTEL_POWERCLAMP
>
> By the way, I found my two Ethernet cards and the can board have the 
> same interrupt number.I removed the igb module.
>
> Is it possible to assign interrupt numbers manuallly? When I started 
> from different kernels, the number is not the same.
>
>
> Good luck!
>
[    0.004106] ENERGY_PERF_BIAS: Set to 'normal', was 'performance'
[    0.004114] ENERGY_PERF_BIAS: View and update with 
x86_energy_perf_policy(8)

I found the above message in the "dmesg" output.
This was solved by:
     sudo modprobe msr
     sudo cd $(knlsrc)/tools/power/x86/x86_energy_perf_policy
     sudo make
     sudo ./x86_energy_perf_policy performance
"rdmsr -a 0x1b0" outputs "6 6 6 6" and "0 0 0 0" previously and 
subsequently.
"wrmsr" should works too.

Re: [Xenomai] Real-time Performance Improvement

[Philippe Gerum]

On 09/26/2016 05:08 AM, Jack Lee wrote:
> 
> 
> On 09/22/2016 02:43 PM, Jack Lee wrote:
>> Hi, everyone,
>>
>> My board is advantech MIO-5251 (J1900 version), linux kernel version
>> is 4.1.18,
>>
>> xenomai version is 3.0.3. As mentioned before, the real-time
>> performance I got was
>>
>> not good.
>>
>> But I found something here:
>> http://rtt-lwr.readthedocs.io/en/latest/rtpc/xenomai.html.
>>
>> After "i915.enable_rc6=0 i915.modset=1 noapic" was added to the kernel
>> command
>>
>> line, the real-time performance improved a lot, which means latency
>> tests (-t0, t1, t2)
>>
>> has no overruns (less than 80us) in 13+ hours, but when other
>> real-time applications
>>
>> was running, overruns occurred sometimes.
>>
>> I found that "intel_powerclamp" "intel_rapl" was in the "lsmod" list.
>> After I removed them,
>>
>> real-time performance of the system is quite good now.
>>
>> I found configs below exist in the original .config file, except
>> "CONFIG_CPU_THERMAL". These
>>
>> configs do not appear on the official website as far as I know. Is it
>> necessary to disable them to
>>
>> improve real-time performance?
>>
>> Generic Thermal sysfs driver
>> CONFIG_THERMAL
>>
>> Fair-share thermal governor
>> CONFIG_THERMAL_GOV_FAIR_SHARE
>>
>> Step_wise thermal governor
>> CONFIG_THERMAL_GOV_STEP_WISE
>>
>> User_space thermal governor
>> CONFIG_THERMAL_GOV_USER_SPACE
>>
>> generic cpu cooling support
>> CONFIG_CPU_THERMAL(n)
>>
>> Thermal emulation mode support
>> CONFIG_THERMAL_EMULATION
>>
>> Intel PowerClamp idle injection driver
>> CONFIG_INTEL_POWERCLAMP
>>
>> By the way, I found my two Ethernet cards and the can board have the
>> same interrupt number.I removed the igb module.
>>
>> Is it possible to assign interrupt numbers manuallly? When I started
>> from different kernels, the number is not the same.
>>
>>
>> Good luck!
>>
> [    0.004106] ENERGY_PERF_BIAS: Set to 'normal', was 'performance'
> [    0.004114] ENERGY_PERF_BIAS: View and update with
> x86_energy_perf_policy(8)
> 
> I found the above message in the "dmesg" output.
> This was solved by:
>     sudo modprobe msr
>     sudo cd $(knlsrc)/tools/power/x86/x86_energy_perf_policy
>     sudo make
>     sudo ./x86_energy_perf_policy performance
> "rdmsr -a 0x1b0" outputs "6 6 6 6" and "0 0 0 0" previously and
> subsequently.
> "wrmsr" should works too.
> 

Since this is a model specific register for the Celeron J1900, could you
point us to the Intel documentation you referred to, to understand what
these settings are doing?

Thanks,

-- 
Philippe.

Re: [Xenomai] Real-time Performance Improvement

[Jack Lee]

On 09/29/2016 02:57 AM, Philippe Gerum wrote:
> On 09/26/2016 05:08 AM, Jack Lee wrote:
>>
>> On 09/22/2016 02:43 PM, Jack Lee wrote:
>>> Hi, everyone,
>>>
>>> My board is advantech MIO-5251 (J1900 version), linux kernel version
>>> is 4.1.18,
>>>
>>> xenomai version is 3.0.3. As mentioned before, the real-time
>>> performance I got was
>>>
>>> not good.
>>>
>>> But I found something here:
>>> http://rtt-lwr.readthedocs.io/en/latest/rtpc/xenomai.html.
>>>
>>> After "i915.enable_rc6=0 i915.modset=1 noapic" was added to the kernel
>>> command
>>>
>>> line, the real-time performance improved a lot, which means latency
>>> tests (-t0, t1, t2)
>>>
>>> has no overruns (less than 80us) in 13+ hours, but when other
>>> real-time applications
>>>
>>> was running, overruns occurred sometimes.
>>>
>>> I found that "intel_powerclamp" "intel_rapl" was in the "lsmod" list.
>>> After I removed them,
>>>
>>> real-time performance of the system is quite good now.
>>>
>>> I found configs below exist in the original .config file, except
>>> "CONFIG_CPU_THERMAL". These
>>>
>>> configs do not appear on the official website as far as I know. Is it
>>> necessary to disable them to
>>>
>>> improve real-time performance?
>>>
>>> Generic Thermal sysfs driver
>>> CONFIG_THERMAL
>>>
>>> Fair-share thermal governor
>>> CONFIG_THERMAL_GOV_FAIR_SHARE
>>>
>>> Step_wise thermal governor
>>> CONFIG_THERMAL_GOV_STEP_WISE
>>>
>>> User_space thermal governor
>>> CONFIG_THERMAL_GOV_USER_SPACE
>>>
>>> generic cpu cooling support
>>> CONFIG_CPU_THERMAL(n)
>>>
>>> Thermal emulation mode support
>>> CONFIG_THERMAL_EMULATION
>>>
>>> Intel PowerClamp idle injection driver
>>> CONFIG_INTEL_POWERCLAMP
>>>
>>> By the way, I found my two Ethernet cards and the can board have the
>>> same interrupt number.I removed the igb module.
>>>
>>> Is it possible to assign interrupt numbers manuallly? When I started
>>> from different kernels, the number is not the same.
>>>
>>>
>>> Good luck!
>>>
>> [    0.004106] ENERGY_PERF_BIAS: Set to 'normal', was 'performance'
>> [    0.004114] ENERGY_PERF_BIAS: View and update with
>> x86_energy_perf_policy(8)
>>
>> I found the above message in the "dmesg" output.
>> This was solved by:
>>      sudo modprobe msr
>>      sudo cd $(knlsrc)/tools/power/x86/x86_energy_perf_policy
>>      sudo make
>>      sudo ./x86_energy_perf_policy performance
>> "rdmsr -a 0x1b0" outputs "6 6 6 6" and "0 0 0 0" previously and
>> subsequently.
>> "wrmsr" should works too.
>>
> Since this is a model specific register for the Celeron J1900, could you
> point us to the Intel documentation you referred to, to understand what
> these settings are doing?
>
> Thanks,
>
Hi, Philippe,
I just googled a lot. This register "0x1b0" is not just for the Celeron 
J1900. It's in intel processors since 2010 (?, can't remember
exactly). Value 0 to 15 means different level of power consumption, 15 
is the most power saving mode. It's all done by the
processor and we can not know the details. The below site said something 
about it. but "epb=" kernel command line
did not work for me.
http://www.phoronix.com/scan.php?page=article&item=ubuntu_linux_epb&num=2
http://lxr.free-electrons.com/diff/tools/power/cpupower/utils/helpers/msr.c?diffval=3.9;diffvar=v
Also it's important to load "msr" module.

Perhaps I will read the Intel documentation one day. Hope that I can 
feedback something for this community.

Good Luck! :)