[RE: [linux-yocto] [PATCH 4/5] x86-64: use the defaults for number of CPUs] On
30/11/2023 (Thu 21:43) Liu, Yongxin wrote:
> > -----Original Message-----
> > From: Gortmaker, Paul <paul.gortma...@windriver.com>
> > Sent: Friday, December 1, 2023 10:27
> > To: Liu, Yongxin <yongxin....@windriver.com>
> > Cc: Bruce Ashfield <bruce.ashfi...@gmail.com>; linux-
> > yo...@lists.yoctoproject.org
> > Subject: Re: [linux-yocto] [PATCH 4/5] x86-64: use the defaults for number
> > of CPUs
> >
> > [RE: [linux-yocto] [PATCH 4/5] x86-64: use the defaults for number of CPUs]
> > On 30/11/2023 (Thu 20:12) Liu, Yongxin wrote:
> >
> > > > -----Original Message-----
> > > > From: linux-yocto@lists.yoctoproject.org <linux-
> > > > yo...@lists.yoctoproject.org> On Behalf Of Paul Gortmaker via
> > > > lists.yoctoproject.org
> > > > Sent: Friday, December 1, 2023 03:08
> > > > To: Bruce Ashfield <bruce.ashfi...@gmail.com>
> > > > Cc: linux-yocto@lists.yoctoproject.org
> > > > Subject: [linux-yocto] [PATCH 4/5] x86-64: use the defaults for
> > > > number of CPUs
> > > >
> > > > From: Paul Gortmaker <paul.gortma...@windriver.com>
> > > >
> > > > The x86-64 BSP isn't quite the same as the "more specific" BSP like
> > > > a Beaglebone Black or the (now deleted) Edgerouter. Where we have
> > > > exact hardware specifics for boards like those, the x86-64 BSP is
> > > > more of a "generic" thing used as the baseline across an endless sea
> > of boards.
> > > >
> > > > To that end, this is somewhat a revert of commit bd77e1f904f6
> > > > ("bsp/intel-x86: change the supported maximum number of CPUs to 512
> > > > in 64- bit bsp")
> > > >
> > > > It is great that a handful of people out there are using Yocto on
> > > > these huge server machines, but that doesn't reflect 99% of the rest
> > > > of us who continue to lean towards the original "embedded theme" of
> > Yocto.
> > > >
> > > > That means a whole bunch of extra per-CPU jumping through hoops;
> > > > some can be mitigated by booting with "nr_cpus=4" (or whatever the
> > > > core count
> > > > is) but I guarantee largely nobody out there is doing that.
> > > >
> > > > Let those users with the crazy CPU count own that config
> > > > customization locally. The default is 64 which still seems way too
> > > > large IMHO, but at least we are moving in the right direction.
> > >
> > >
> > > This intel-x86-64 BSP is a generic one used from mobile to server.
> > >
> > > Customers need to customize not only the CPU number config but also
> > > other configs, like, removing unused drivers or adding debug options.
> > > From this point of view, there is no difference between 64 or 512.
>
> I changed 64 to 512. Because we have server machines with more than 64 CPU.
> I want the BSP support those machines by default.
But you still miss the point. It doesn't matter what you or any company
"want" in this case. Like it or not, it is a shared resource and so the
defaults have to be what is good for Yocto project and not for *you*
>
> >
> > So you've basically argued my case for me. If changes are inevitable,
> > then why do we change the default?
> >
> > > But it changes the "rule" that intel-x86-64 works for all supported
> > platforms.
> > > We need to do extra work for servers with large CPU number.
> >
> > No. There is no "rule" in Yocto like that. That is nonsense because
> > there is no way Yocto can commit to "support" all the crazy different
> > x86-64 variants out there.
>
>
> I think this "bsp/intel-x86" is used only by Wind River.
> So bsp/intel-x86 should work for all supported machines claimed by Wind River.
No. That is where you are dead wrong. Wind River does not own Yocto.
Think for a minute. A new Yocto user comes along and sees "intel-x86"
and because that name is so generic -- thinks "I'll build that for my old PC."
> If we need to do some local change to support some machine. That's not good.
> Because people usually build image with default configs and then complain
> something doesn't work.
Again, it is NOT the problem of the Yocto project what isn't good for YOU.
If you need EDAC and NUMA and 500+ CPU support, then make a proper BSP
with those settings and submit it as "bsp/mega-server-2000" or whatever.
Don't just be using intel-x86 as a dumping ground for whatever random
setting you need today. That isn't fair to all the other Yocto users
out there who might not even know who Wind River is.
Paul.
--
>
>
> Thanks,
> Yongxin
>
>
> > If a re-seller/integrator wants to take Yocto and tune it for platform XYZ
> > because there is customer demand and claim it is then "supported" by them,
> > then fine. But then to expect the Yocto project to own that? No.
>
>
> >
> > Paul.
> > --
> >
> > >
> > > Thanks,
> > > Yongxin
> > >
> > > >
> > > > Signed-off-by: Paul Gortmaker <paul.gortma...@windriver.com>
> > > > ---
> > > > bsp/intel-x86/intel-x86-64.cfg | 3 ---
> > > > 1 file changed, 3 deletions(-)
> > > >
> > > > diff --git a/bsp/intel-x86/intel-x86-64.cfg
> > > > b/bsp/intel-x86/intel-x86- 64.cfg index 58b0fed637e8..da9bc7b57eca
> > > > 100644
> > > > --- a/bsp/intel-x86/intel-x86-64.cfg
> > > > +++ b/bsp/intel-x86/intel-x86-64.cfg
> > > > @@ -31,6 +31,3 @@ CONFIG_CRYPTO_DEV_QAT_DH895xCCVF=m
> > > >
> > > > # x86 CPU resource control support
> > > > CONFIG_X86_CPU_RESCTRL=y
> > > > -
> > > > -# Processor type and features
> > > > -CONFIG_NR_CPUS=512
> > > > --
> > > > 2.40.0
> > >
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