[Xenomai-help] Xenomai installation: high latencies

[Xenomai-help] Xenomai installation: high latencies

[Kurt Geebelen]

Dear all,

I've tried installing Xenomai, following these instructions:

http://www.xenomai.org/index.php/Building_Debian_packages

but then for the latest version (xenomai 2.6.0, and kernel 2.6.38.8 and 
for 64 bit) .

For configuring the kernel, I followed these instructions:

http://www.xenomai.org/index.php/Configuring_x86_kernels

All that is stated on these websites works without problems, and I am 
able to boot in the installed xenomai kernel. However, when I perform 
the latency-test (latency in /usr/lib/xenomai), I get latencies of more 
than 1400 microseconds.

The system I have is the following:

Dell™ Precision™ T1500
One® Intel™ Core i7-860 (2.8GHz, 8MB L3, 95W, Quad Core)
6GB DDR3 non-ECC Memory (1333MHz, 3x2GB)
512MB PCIe x16 NVIDIA Quadro FX 580 Graphics Card
Intel Solid-State Drive 320 Series 120GB

I have tried reinstalling the kernel several times, but I always end up 
with high latencies.
I also have consulted with others, who followed the same guidelines as I 
did, and their latencies are about 100 times lower.

Is there somebody who knows what the problem might be? Might it be a 
hardware-related problem?

Many thanks in advance,
Best regards,
Kurt Geebelen

Re: [Xenomai-help] Xenomai installation: high latencies

[Jan Kiszka]

On 2011-12-02 16:28, Kurt Geebelen wrote:
> Dear all,
> 
> I've tried installing Xenomai, following these instructions:
> 
> http://www.xenomai.org/index.php/Building_Debian_packages
> 
> but then for the latest version (xenomai 2.6.0, and kernel 2.6.38.8 and
> for 64 bit) .
> 
> For configuring the kernel, I followed these instructions:
> 
> http://www.xenomai.org/index.php/Configuring_x86_kernels
> 
> All that is stated on these websites works without problems, and I am
> able to boot in the installed xenomai kernel. However, when I perform
> the latency-test (latency in /usr/lib/xenomai), I get latencies of more
> than 1400 microseconds.

Sounds like wbinvd (cache flushing on DMA remappings).

> 
> The system I have is the following:
> 
> Dell™ Precision™ T1500
> One® Intel™ Core i7-860 (2.8GHz, 8MB L3, 95W, Quad Core)
> 6GB DDR3 non-ECC Memory (1333MHz, 3x2GB)
> 512MB PCIe x16 NVIDIA Quadro FX 580 Graphics Card

Do you use the nvidia binary driver? It's known to kill latencies.


> Intel Solid-State Drive 320 Series 120GB
> 
> I have tried reinstalling the kernel several times, but I always end up
> with high latencies.
> I also have consulted with others, who followed the same guidelines as I
> did, and their latencies are about 100 times lower.
> 
> Is there somebody who knows what the problem might be? Might it be a
> hardware-related problem?
> 
> Many thanks in advance,
> Best regards,
> Kurt Geebelen

Jan

-- 
Siemens AG, Corporate Technology, CT T DE IT 1
Corporate Competence Center Embedded Linux

Re: [Xenomai-help] Xenomai installation: high latencies

[Uwe Fechner]

Hi Kurt,

did you look at my website:
http://www.kieltech.de/uweswiki/Xenomai

I had to globally disable system management interrupts, to get the latencies down.

Regards:

Uwe

Am 02.12.2011 16:28, schrieb Kurt Geebelen:
> Dear all,
>
> I've tried installing Xenomai, following these instructions:
>
> http://www.xenomai.org/index.php/Building_Debian_packages
>
> but then for the latest version (xenomai 2.6.0, and kernel 2.6.38.8 and for 64 bit) .
>
> For configuring the kernel, I followed these instructions:
>
> http://www.xenomai.org/index.php/Configuring_x86_kernels
>
> All that is stated on these websites works without problems, and I am able to boot in the 
> installed xenomai kernel. However, when I perform the latency-test (latency in /usr/lib/xenomai), 
> I get latencies of more than 1400 microseconds.
>
> The system I have is the following:
>
> Dell™ Precision™ T1500
> One® Intel™ Core i7-860 (2.8GHz, 8MB L3, 95W, Quad Core)
> 6GB DDR3 non-ECC Memory (1333MHz, 3x2GB)
> 512MB PCIe x16 NVIDIA Quadro FX 580 Graphics Card
> Intel Solid-State Drive 320 Series 120GB
>
> I have tried reinstalling the kernel several times, but I always end up with high latencies.
> I also have consulted with others, who followed the same guidelines as I did, and their latencies 
> are about 100 times lower.
>
> Is there somebody who knows what the problem might be? Might it be a hardware-related problem?
>
> Many thanks in advance,
> Best regards,
> Kurt Geebelen
>
> _______________________________________________
> Xenomai-help mailing list
> Xenomai-help@domain.hid
> https://mail.gna.org/listinfo/xenomai-help

Re: [Xenomai-help] Xenomai installation: high latencies

[George Broz]

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Hi Kurt,

I had to disable all CPU throttling mechanisms in the BIOS settings like 
Intel's SpeedStep and ACPI 3.0 T-states. Make sure you have adequate 
cooling if you do so!

Regards,
George

<xenomai-help-bounces@domain.hid> wrote on 12/02/2011 07:28:49 AM:

> Dear all,
> 
> I've tried installing Xenomai, following these instructions:
> 
> http://www.xenomai.org/index.php/Building_Debian_packages
> 
> but then for the latest version (xenomai 2.6.0, and kernel 2.6.38.8 and 
> for 64 bit) .
> 
> For configuring the kernel, I followed these instructions:
> 
> http://www.xenomai.org/index.php/Configuring_x86_kernels
> 
> All that is stated on these websites works without problems, and I am 
> able to boot in the installed xenomai kernel. However, when I perform 
> the latency-test (latency in /usr/lib/xenomai), I get latencies of more 
> than 1400 microseconds.
> 
> The system I have is the following:
> 
> Dell? Precision? T1500
> One® Intel? Core i7-860 (2.8GHz, 8MB L3, 95W, Quad Core)
> 6GB DDR3 non-ECC Memory (1333MHz, 3x2GB)
> 512MB PCIe x16 NVIDIA Quadro FX 580 Graphics Card
> Intel Solid-State Drive 320 Series 120GB
> 
> I have tried reinstalling the kernel several times, but I always end up 
> with high latencies.
> I also have consulted with others, who followed the same guidelines as I 

> did, and their latencies are about 100 times lower.
> 
> Is there somebody who knows what the problem might be? Might it be a 
> hardware-related problem?
> 
> Many thanks in advance,
> Best regards,
> Kurt Geebelen
> 
> _______________________________________________
> Xenomai-help mailing list
> Xenomai-help@domain.hid
> https://mail.gna.org/listinfo/xenomai-help
> 

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Re: [Xenomai-help] Xenomai installation: high latencies

[Gilles Chanteperdrix]

On 12/02/2011 04:28 PM, Kurt Geebelen wrote:
> Dear all,
> 
> I've tried installing Xenomai, following these instructions:
> 
> http://www.xenomai.org/index.php/Building_Debian_packages
> 
> but then for the latest version (xenomai 2.6.0, and kernel 2.6.38.8 and 
> for 64 bit) .
> 
> For configuring the kernel, I followed these instructions:
> 
> http://www.xenomai.org/index.php/Configuring_x86_kernels
> 
> All that is stated on these websites works without problems, and I am 
> able to boot in the installed xenomai kernel. However, when I perform 
> the latency-test (latency in /usr/lib/xenomai), I get latencies of more 
> than 1400 microseconds.
> 
> The system I have is the following:
> 
> Dell™ Precision™ T1500
> One® Intel™ Core i7-860 (2.8GHz, 8MB L3, 95W, Quad Core)
> 6GB DDR3 non-ECC Memory (1333MHz, 3x2GB)
> 512MB PCIe x16 NVIDIA Quadro FX 580 Graphics Card
> Intel Solid-State Drive 320 Series 120GB
> 
> I have tried reinstalling the kernel several times, but I always end up 
> with high latencies.
> I also have consulted with others, who followed the same guidelines as I 
> did, and their latencies are about 100 times lower.
> 
> Is there somebody who knows what the problem might be? Might it be a 
> hardware-related problem?

It is already written in the URL you mention, but I will repeat it
nevertheless, if enabling SMI workaround, have you checked the kernel
logs to see whether the SMI workaround actually works?

-- 
					    Gilles.

Re: [Xenomai-help] Xenomai installation: high latencies

[Kurt Geebelen]

Hi all,

Sorry for taking so long to respond, I didn't have time to work on it. 
SMI's didn't appear to be the problem, and I also am not using the 
nvidia binary driver.

I tried disabling USB in the BIOS, and that helped! My latencies are now 
under 6 microseconds. Since I don't need USB (I'm using a PS/2 mouse and 
keyboard now), I'll use it like this.

Thanks for the help,
Best,
Kurt

Op 6/12/2011 19:12, Gilles Chanteperdrix schreef:
> On 12/02/2011 04:28 PM, Kurt Geebelen wrote:
>> Dear all,
>>
>> I've tried installing Xenomai, following these instructions:
>>
>> http://www.xenomai.org/index.php/Building_Debian_packages
>>
>> but then for the latest version (xenomai 2.6.0, and kernel 2.6.38.8 and
>> for 64 bit) .
>>
>> For configuring the kernel, I followed these instructions:
>>
>> http://www.xenomai.org/index.php/Configuring_x86_kernels
>>
>> All that is stated on these websites works without problems, and I am
>> able to boot in the installed xenomai kernel. However, when I perform
>> the latency-test (latency in /usr/lib/xenomai), I get latencies of more
>> than 1400 microseconds.
>>
>> The system I have is the following:
>>
>> Dell™ Precision™ T1500
>> One® Intel™ Core i7-860 (2.8GHz, 8MB L3, 95W, Quad Core)
>> 6GB DDR3 non-ECC Memory (1333MHz, 3x2GB)
>> 512MB PCIe x16 NVIDIA Quadro FX 580 Graphics Card
>> Intel Solid-State Drive 320 Series 120GB
>>
>> I have tried reinstalling the kernel several times, but I always end up
>> with high latencies.
>> I also have consulted with others, who followed the same guidelines as I
>> did, and their latencies are about 100 times lower.
>>
>> Is there somebody who knows what the problem might be? Might it be a
>> hardware-related problem?
> It is already written in the URL you mention, but I will repeat it
> nevertheless, if enabling SMI workaround, have you checked the kernel
> logs to see whether the SMI workaround actually works?
>

Re: [Xenomai-help] Xenomai installation: high latencies

[Gilles Chanteperdrix]

On 12/07/2011 03:37 PM, Kurt Geebelen wrote:
> Hi all,
> 
> Sorry for taking so long to respond, I didn't have time to work on it. 
> SMI's didn't appear to be the problem, and I also am not using the 
> nvidia binary driver.
> 
> I tried disabling USB in the BIOS, and that helped! My latencies are now 
> under 6 microseconds. Since I don't need USB (I'm using a PS/2 mouse and 
> keyboard now), I'll use it like this.

Usually, only legacy USB emulation is a source of problems. You can
disable it in BIOS configuration. Sometimes, enabling USB in kernel
configuration (and loading USB modules at run time) is enough as the USB
modules disable legacy emulation as part of their initialization.

-- 
					    Gilles.