SMP on different cores.

SMP on different cores.

[Madhu K]

Hi All,

If i want to enable SMP, cores should be of same version( ex: both core
should ARM 7 ) or we could enable SMP on different version.

Thanks
Madhu
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SMP on different cores.

[Greg KH]

On Thu, Sep 22, 2016 at 04:46:12PM +0530, Madhu K wrote:
> Hi All,
> 
> If i want to enable SMP, cores should be of same version( ex: both
> core should ARM 7 ) or we could enable SMP on different version.

Do you have a machine that has cores of different versions of a CPU?  If
so, what are they?

thanks,

greg k-h

SMP on different cores.

[Daniel.]

I know about i.MX6 which has Cortex-A7 + Cortex-M4... but I don't
think that M4 is handled by Linux but by some RTOS

2016-09-22 9:17 GMT-03:00 Greg KH <greg@kroah.com>:
> On Thu, Sep 22, 2016 at 04:46:12PM +0530, Madhu K wrote:
>> Hi All,
>>
>> If i want to enable SMP, cores should be of same version( ex: both
>> core should ARM 7 ) or we could enable SMP on different version.
>
> Do you have a machine that has cores of different versions of a CPU?  If
> so, what are they?
>
> thanks,
>
> greg k-h
>
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
> https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies



-- 
"Do or do not. There is no try"
  Yoda Master

SMP on different cores.

[Daniel.]

s/iMX6/iMX7/

2016-09-22 10:04 GMT-03:00 Daniel. <danielhilst@gmail.com>:
> I know about i.MX6 which has Cortex-A7 + Cortex-M4... but I don't
> think that M4 is handled by Linux but by some RTOS
>
> 2016-09-22 9:17 GMT-03:00 Greg KH <greg@kroah.com>:
>> On Thu, Sep 22, 2016 at 04:46:12PM +0530, Madhu K wrote:
>>> Hi All,
>>>
>>> If i want to enable SMP, cores should be of same version( ex: both
>>> core should ARM 7 ) or we could enable SMP on different version.
>>
>> Do you have a machine that has cores of different versions of a CPU?  If
>> so, what are they?
>>
>> thanks,
>>
>> greg k-h
>>
>> _______________________________________________
>> Kernelnewbies mailing list
>> Kernelnewbies at kernelnewbies.org
>> https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>
>
>
> --
> "Do or do not. There is no try"
>   Yoda Master



-- 
"Do or do not. There is no try"
  Yoda Master

SMP on different cores.

[Valdis.Kletnieks at vt.edu]

On Thu, 22 Sep 2016 16:46:12 +0530, Madhu K said:

> If i want to enable SMP, cores should be of same version( ex: both core
> should ARM 7 ) or we could enable SMP on different version.

There's kernel support for the bigLITTLE architecture in some ARM chips,
but since it depends on being able to migrate execution streams between
them, the various processors really *do* need to be compatible.

You *really* don't want to try to make things work when some cores are
ARM6 and some are ARM7, for instance - that way lies madness if you ever
reschedule onto a different processor (and I'm not even sure our toolchains
are able to generate a mixed-architecture binary without complaint).
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SMP on different cores.

[Madhu K]

Hi Greg k-h,

Thanks a lot for your response.

I want to understand how SMP works and what should be the requirements to
enable SMP, This is to understand, whether is it possible to enable SMP on
different cores. Right now I don't have a machine with different cores.

Thanks
Madhu

On Thu, Sep 22, 2016 at 5:47 PM, Greg KH <greg@kroah.com> wrote:

> On Thu, Sep 22, 2016 at 04:46:12PM +0530, Madhu K wrote:
> > Hi All,
> >
> > If i want to enable SMP, cores should be of same version( ex: both
> > core should ARM 7 ) or we could enable SMP on different version.
>
> Do you have a machine that has cores of different versions of a CPU?  If
> so, what are they?
>
> thanks,
>
> greg k-h
>
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SMP on different cores.

[Greg KH]

On Fri, Sep 23, 2016 at 04:30:58PM +0530, Madhu K wrote:
> Hi Greg k-h,
> 
> Thanks a lot for your response.
> 
> I want to understand how SMP works and what should be the requirements to
> enable SMP, This is to understand, whether is it possible to enable SMP on
> different cores. Right now I don't have a machine with different cores.

There is lots of documentation and information out there about SMP and
how it works.  I suggest doing a bit of research first, and if you have
questions about the Linux implementation of such, we would be glad to
help answer specific questions.

good luck!

greg k-h

SMP on different cores.

[Greg Freemyer]

On Fri, Sep 23, 2016 at 7:00 AM, Madhu K <madhu.sk89@gmail.com> wrote:
> Hi Greg k-h,
>
> Thanks a lot for your response.
>
> I want to understand how SMP works and what should be the requirements to
> enable SMP, This is to understand, whether is it possible to enable SMP on
> different cores. Right now I don't have a machine with different cores.
>
> Thanks
> Madhu
>
> On Thu, Sep 22, 2016 at 5:47 PM, Greg KH <greg@kroah.com> wrote:
>>
>> On Thu, Sep 22, 2016 at 04:46:12PM +0530, Madhu K wrote:
>> > Hi All,
>> >
>> > If i want to enable SMP, cores should be of same version( ex: both
>> > core should ARM 7 ) or we could enable SMP on different version.
>>
>> Do you have a machine that has cores of different versions of a CPU?  If
>> so, what are they?
>>
>> thanks,
>>
>> greg k-h

Madhu,

SMP requires a single computer with multiple cores.  If and when you
buy a computer with multiple cores, I encourage you to buy one where
all the cores are the same.

BTW: in both Arm and Intel, the lowest end multi-core CPU PCs use a
single socket solution, so you have absolutely no option of having
different architectures on that single socket.

Greg (not KH)