arm/arm64 ipipe performance

arm/arm64 ipipe performance

[Greg Gallagher]

Hi Everyone,
   There's been a noticeable slow down in the arm and arm64 latency of
late.  I tracked the issue
 down to the tracing infrastructure.  For now if you hit this issue,
disable ftrace.  Once this is done the latency numbers look much better.
I'm currently working on resolving the issue.

  New patches will be released this week for both arm and arm64 now that
the issue is understood and a work around exists.

Thanks

Greg

Re: arm/arm64 ipipe performance

[Jan Kiszka]

On 18.05.21 20:28, Greg Gallagher via Xenomai wrote:
> Hi Everyone,
>    There's been a noticeable slow down in the arm and arm64 latency of
> late.  I tracked the issue
>  down to the tracing infrastructure.  For now if you hit this issue,
> disable ftrace.  Once this is done the latency numbers look much better.
> I'm currently working on resolving the issue.

Do you mean disabling during build? Or is the issue only present when
tracing is actively used during runtime?

> 
>   New patches will be released this week for both arm and arm64 now that
> the issue is understood and a work around exists.
> 

That's great!

Jan

-- 
Siemens AG, T RDA IOT
Corporate Competence Center Embedded Linux

Re: arm/arm64 ipipe performance

[Greg Gallagher]

On Tue, May 18, 2021 at 2:49 PM Jan Kiszka <jan.kiszka@siemens.com> wrote:

> On 18.05.21 20:28, Greg Gallagher via Xenomai wrote:
> > Hi Everyone,
> >    There's been a noticeable slow down in the arm and arm64 latency of
> > late.  I tracked the issue
> >  down to the tracing infrastructure.  For now if you hit this issue,
> > disable ftrace.  Once this is done the latency numbers look much better.
> > I'm currently working on resolving the issue.
>
> Do you mean disabling during build? Or is the issue only present when
> tracing is actively used during runtime?




>
> >
> >   New patches will be released this week for both arm and arm64 now that
> > the issue is understood and a work around exists.
> >
>
> That's great!
>
> Jan
>
> --
> Siemens AG, T RDA IOT
> Corporate Competence Center Embedded Linux


Hi,
   I mean disabled during build time. That’s at least how I tested to see
that the issue went away. Hopefully I’ll have a solution soon.

Thanks

Greg

Re: arm/arm64 ipipe performance

[Robert Berger]

Hi,

On 18/05/2021 22:06, Greg Gallagher via Xenomai wrote:
> On Tue, May 18, 2021 at 2:49 PM Jan Kiszka <jan.kiszka@siemens.com> wrote:
> 
> 
> Hi,
>     I mean disabled during build time. That’s at least how I tested to see
> that the issue went away. Hopefully I’ll have a solution soon.
> 
> Thanks
> 
> Greg
> 

I guess that's the reason I didn't notice anything strange with my 
cyclictest/jitter measurements. I use a pretty minimal kernel config.

Regards,

Robert

Re: arm/arm64 ipipe performance

[liandao]

hi greg gallagher,
    is this mean:the ipipe-core-5.4.119-arm64-2 released on 5/23 also
should turn off ftrace when config kernel?

On 5/19/21, Greg Gallagher via Xenomai <xenomai@xenomai.org> wrote:
> Hi Everyone,
>    There's been a noticeable slow down in the arm and arm64 latency of
> late.  I tracked the issue
>  down to the tracing infrastructure.  For now if you hit this issue,
> disable ftrace.  Once this is done the latency numbers look much better.
> I'm currently working on resolving the issue.
>
>   New patches will be released this week for both arm and arm64 now that
> the issue is understood and a work around exists.
>
> Thanks
>
> Greg
>

Re: arm/arm64 ipipe performance

[Greg Gallagher]

On Tue, May 25, 2021 at 6:43 AM liandao <liandao@gmail.com> wrote:

> hi greg gallagher,
>     is this mean:the ipipe-core-5.4.119-arm64-2 released on 5/23 also
> should turn off ftrace when config kernel?
>
> On 5/19/21, Greg Gallagher via Xenomai <xenomai@xenomai.org> wrote:
> > Hi Everyone,
> >    There's been a noticeable slow down in the arm and arm64 latency of
> > late.  I tracked the issue
> >  down to the tracing infrastructure.  For now if you hit this issue,
> > disable ftrace.  Once this is done the latency numbers look much better.
> > I'm currently working on resolving the issue.
> >
> >   New patches will be released this week for both arm and arm64 now that
> > the issue is understood and a work around exists.
> >
> > Thanks
> >
> > Greg
> >


Yes the same for arm64. I believe I’ve found the issue but for this release
ftrace should not be included in the build to get optimal performance.

Thanks

Greg

>
>