Re: [gentoo-dev] Major MCE problem with SMP on Gentoo kernels

[Josh Glover]

Quoth Kevin (Wed 2004-05-12 07:24:07AM -0400):

> On Tuesday 11 May 2004 22:42, Josh Glover wrote:
>
> > Quoth Kevin (Tue 2004-05-11 02:07:58PM -0400):
> >
> > > The machine is a Dell PowerEdge1600SC with a PERC-3/SC SCSI RAID
> > > controller (using AMI megaraid2 driver) and a LSI Logic Corp
> > > controller (using Fusion MPT base driver) for the SCSI DAT and with
> > > dual 2.4GHz Xeon processors, each having a 512KB L2 Cache.
> >
> > Running Gentoo with a 2.6.5 SMP kernel on a Dell PowerEdge 400SC:
> > : jmglov@jglover; uname -a
> >
> > Linux jglover 2.6.5-gentoo-r1 #1 SMP Fri Apr 30 17:37:18 EDT 2004 i686
> > Intel(R) Pentium(R) 4 CPU 2.40GHz GenuineIntel GNU/Linux
> >
> > : jmglov@jglover; cat /proc/cpuinfo
> >
> > processor       : 0

[...]

> > processor       : 1
>
> Have you turned off hyperthreading?  Why is it that only two CPUs show up?
> It looks like (flags include ht) the CPUs support hyperthreading... or am
> I way off base in drawing that conclusion here?

No, the only part where you went off base was in assuming that I have more
than one *physical* CPU in the box. I have one, and with hyperthreading
turned on, it looks like two to the kernel.

> Well, last night I did the most exhaustive set of tests available on the
> Dell Utility Partition and found zero errors.  I did 16 loops of the MATS
> test and 15 of TestY, TestA, and ECC coupling.  The memory tests ran for
> about 8 hours.  Again, zero errors.

[...]

> > I recommend doing at
> > least one Stage 1 install for newcomers to Gentoo, just for educational
> > purposes, but after that, go Stage 3 and use as many binary packages as
> > you can! There exists a Stage 3 tarball for your architecture--the
> > Pentium4 one, so why not use that, just to make sure your base system
> > is solid?
>
> That probably is a good thing for me to try next, and I really would like
> to be able to use all the advantages of Gentoo on this server.  I'm fed
> up with rpm hell and the traditional distros drawbacks.

Yes, I really think that if you use a Stage 3, you can feel pretty
confident about your C compiler and libraries being stable. Just be
careful when you compile your kernel!

> > > Are there some compiler flags or other configurable settings that, if
> > > set to certain values during the bootstrap.sh or emerge system steps,
> > > could end up generating software (perhaps when I built my own gcc?)
> > > that would cause these MCEs to be thrown?
> >
> > I dunno, why don't you post your CFLAGS and MAKEOPTS from your
> > make.conf here?
>
> Did already :)

Lost them in the spew, sorry.

> Here they are again:
>
> ACCEPT_KEYWORDS="x86"

This is unnecessary. You only need to use ACCEPT_KEYWORDS with the
unstable keywords, ~x86 in your case.

> CFLAGS="-O3 -march=pentium4 -pipe -fomit-frame-pointer"

Might want to back off to -O2, at least when you compile the kernel if
nothing else. I believe the handbook recommends -O2, and optimising too
highly can lead to some pretty bizarre problems.

> CXXFLAGS="-O3 -march=pentium4

I am not sure if you are setting this, or if this is just emerge, but
you usually want to set CXXFLAGS="${CFLAGS}".

> FEATURES="autoaddcvs ccache distcc sandbox"

autoaddcvs is a feature only for developers, you should not turn it on.

> MAKEOPTS="-j3"

You have four CPUs, so set this to -j5.

> Thanks again for the thoughtful reply, Josh.

Hey, I live to serve. :)

-- 
Josh Glover

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