On Thu, Nov 30, 2023 at 11:38 PM Liu, Yongxin <yongxin....@windriver.com> wrote:
>
> > -----Original Message-----
> > From: Gortmaker, Paul <paul.gortma...@windriver.com>
> > Sent: Friday, December 1, 2023 11:14
> > 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 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."
>
> I have a question why we need bsp/intel-x86, because Yocto already has
> bsp/intel-common and bsp/common-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.
>
> Then I think we should revise bsp/intel-x86, because it has enabled many
> uncommon features by
>
> intel-x86.scc:include features/intel-idxd/intel-idxd.scc
> intel-x86.scc:include
> features/intel-uncore-frequency/intel-uncore-frequency.scc
> intel-x86.scc:include features/intel-dptf/intel-dptf.scc
> intel-x86.scc:include features/can/m_can.scc
> intel-x86.scc:include features/vfio/vfio.scc
> intel-x86.scc:include features/i3c/i3c.scc
>
> We should move them to our own bsp layer to make bsp/intel-x86 more generic,
> right?
>
I'd suggest that we keep the current configuration around, but as Paul
suggests, under a more specific name to indicate that it targets a class
of machines that are server class. Perhaps even something like x86-server ?
At the same time, we could take the changes to make the more generically
named machine ... more generic. There's value in keeping both around and
in the common kernel-cache.
Bruce
>
> Thanks,
> Yongxin
>
>
> >
> > 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
> > > > >
--
- Thou shalt not follow the NULL pointer, for chaos and madness await
thee at its end
- "Use the force Harry" - Gandalf, Star Trek II
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