CPU Affinity

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CPU Affinity

Elias M. Mariani
Hi,
I was trying to port mprime to OpenBSD.
The main issue is not finding any way to set affinity on cores.
Searching for how to do this on OpenBSD bring this result in undeadly:
http://undeadly.org/cgi?action=article&sid=20090324210236

Is CPU Affinity dropped out of OpenBSD for some reason?

Elias.

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Re: CPU Affinity

lists-2
Sun, 29 Apr 2018 22:07:18 -0300 "Elias M. Mariani"
<[hidden email]>

> Hi,
> I was trying to port mprime to OpenBSD.
> The main issue is not finding any way to set affinity on cores.
> Searching for how to do this on OpenBSD bring this result in undeadly:
> http://undeadly.org/cgi?action=article&sid=20090324210236
>
> Is CPU Affinity dropped out of OpenBSD for some reason?
>
> Elias.
>

Hi Elias,

Why do you want to do the operating system duty in user level programs?

Kind regards,
Anton Lazarov

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Re: CPU Affinity

Elias M. Mariani
Hi Anton,
The why is:
An increase in performance.
In this case I want to use some cores to do a very large operation and
it will be faster if the same core continues the same operation.
Maybe there's a library for doing so, or a way that I dont know in OpenBSD.
Now, this cases come not very often, and is debatible (probably
already debated in this proyect) that if that's the case you should
run a variation of the scheduler or use other OS.
And is true...
Now, in this moment I see a lot of activity around vmd/vmm, I have
been using it myself, is great, I love it, but my guess is that you
can get more performance on the guests OS if you set the affinity of
the process.
Maybe this is already done, or may will be... If that's the case
either you added functionality to the OS for supporting affinity or
you made vmm part of the OS, and there is the back question.
If you add vmm as part of the OS you are "extending" the system duty
to be a host, if you add affinity support you are doing the same...
Anyways, the proyect clearly knows itself and if there is no affinity
support is OK. Still loving OpenBSD.
The low punch would be discuss about "nice" support, but lets leave
that aside, I dont want a fight like in other post about philosophy
and low punches.

Now in MY PARTICULAR CASE, I usually do large math calculations, I've
been using other OSes but I love OpenBSD, so I ported my most used
tool, spyder (for writing python).
I love to test algorithms and things for a large time and things like
that. That is my taste, and is not an obligation for OpenBSD to
support affinity just because I want (Its obvious), but I see lots of
applications for "user level programs", for example vmm, pf, and
others components, I dont know if PF and VMM are "user level
programs", if they are you are already doing things that might be seen
as "not OS duty", if they are not, they would benefit probably of
affinity.

Just my opinion, again, dont do of this remarks something that it is not...
I just kindly ask about a funcionality, because I want to use my
favorite OS, made right, and test algorithms and look for big prime
numbers on it. If there is no funcionality, then, Its my problem...
Elias.

2018-04-29 23:15 GMT-03:00  <[hidden email]>:

> Sun, 29 Apr 2018 22:07:18 -0300 "Elias M. Mariani"
> <[hidden email]>
>> Hi,
>> I was trying to port mprime to OpenBSD.
>> The main issue is not finding any way to set affinity on cores.
>> Searching for how to do this on OpenBSD bring this result in undeadly:
>> http://undeadly.org/cgi?action=article&sid=20090324210236
>>
>> Is CPU Affinity dropped out of OpenBSD for some reason?
>>
>> Elias.
>>
>
> Hi Elias,
>
> Why do you want to do the operating system duty in user level programs?
>
> Kind regards,
> Anton Lazarov

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Re: CPU Affinity

Peter Hessler
In reply to this post by Elias M. Mariani
On 2018 Apr 29 (Sun) at 22:07:18 -0300 (-0300), Elias M. Mariani wrote:
:Hi,
:I was trying to port mprime to OpenBSD.
:The main issue is not finding any way to set affinity on cores.
:Searching for how to do this on OpenBSD bring this result in undeadly:
:http://undeadly.org/cgi?action=article&sid=20090324210236
:
:Is CPU Affinity dropped out of OpenBSD for some reason?
:
:Elias.
:

CPU Affinity is available inside the kernel only, and is not exposed to
userland.

There are no plans to make it available to userland.


--
Pardon this fortune.  Database under reconstruction.

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Re: CPU Affinity

Mike Larkin
In reply to this post by Elias M. Mariani
On Mon, Apr 30, 2018 at 01:02:56AM -0300, Elias M. Mariani wrote:

> Hi Anton,
> The why is:
> An increase in performance.
> In this case I want to use some cores to do a very large operation and
> it will be faster if the same core continues the same operation.
> Maybe there's a library for doing so, or a way that I dont know in OpenBSD.
> Now, this cases come not very often, and is debatible (probably
> already debated in this proyect) that if that's the case you should
> run a variation of the scheduler or use other OS.
> And is true...
> Now, in this moment I see a lot of activity around vmd/vmm, I have
> been using it myself, is great, I love it, but my guess is that you
> can get more performance on the guests OS if you set the affinity of
> the process.

vmd(8) CPU affinity should bethe absolute least of your concerns WRT
vmm/vmd performance. There has been basically zero effort to optimize
this area yet.

-ml


> Maybe this is already done, or may will be... If that's the case
> either you added functionality to the OS for supporting affinity or
> you made vmm part of the OS, and there is the back question.
> If you add vmm as part of the OS you are "extending" the system duty
> to be a host, if you add affinity support you are doing the same...
> Anyways, the proyect clearly knows itself and if there is no affinity
> support is OK. Still loving OpenBSD.
> The low punch would be discuss about "nice" support, but lets leave
> that aside, I dont want a fight like in other post about philosophy
> and low punches.
>
> Now in MY PARTICULAR CASE, I usually do large math calculations, I've
> been using other OSes but I love OpenBSD, so I ported my most used
> tool, spyder (for writing python).
> I love to test algorithms and things for a large time and things like
> that. That is my taste, and is not an obligation for OpenBSD to
> support affinity just because I want (Its obvious), but I see lots of
> applications for "user level programs", for example vmm, pf, and
> others components, I dont know if PF and VMM are "user level
> programs", if they are you are already doing things that might be seen
> as "not OS duty", if they are not, they would benefit probably of
> affinity.
>
> Just my opinion, again, dont do of this remarks something that it is not...
> I just kindly ask about a funcionality, because I want to use my
> favorite OS, made right, and test algorithms and look for big prime
> numbers on it. If there is no funcionality, then, Its my problem...
> Elias.
>
> 2018-04-29 23:15 GMT-03:00  <[hidden email]>:
> > Sun, 29 Apr 2018 22:07:18 -0300 "Elias M. Mariani"
> > <[hidden email]>
> >> Hi,
> >> I was trying to port mprime to OpenBSD.
> >> The main issue is not finding any way to set affinity on cores.
> >> Searching for how to do this on OpenBSD bring this result in undeadly:
> >> http://undeadly.org/cgi?action=article&sid=20090324210236
> >>
> >> Is CPU Affinity dropped out of OpenBSD for some reason?
> >>
> >> Elias.
> >>
> >
> > Hi Elias,
> >
> > Why do you want to do the operating system duty in user level programs?
> >
> > Kind regards,
> > Anton Lazarov
>

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Re: CPU Affinity

Elias M. Mariani
In reply to this post by Peter Hessler
Thanks for the reply Peter.
May I ask why is not available to userland?
Is just a developers decision or is because no one is interested in
that functionality?

Elias.

2018-04-30 3:32 GMT-03:00 Peter Hessler <[hidden email]>:

> On 2018 Apr 29 (Sun) at 22:07:18 -0300 (-0300), Elias M. Mariani wrote:
> :Hi,
> :I was trying to port mprime to OpenBSD.
> :The main issue is not finding any way to set affinity on cores.
> :Searching for how to do this on OpenBSD bring this result in undeadly:
> :http://undeadly.org/cgi?action=article&sid=20090324210236
> :
> :Is CPU Affinity dropped out of OpenBSD for some reason?
> :
> :Elias.
> :
>
> CPU Affinity is available inside the kernel only, and is not exposed to
> userland.
>
> There are no plans to make it available to userland.
>
>
> --
> Pardon this fortune.  Database under reconstruction.
>