Re: Intel Hyperthreading problem on server?
I was also considering the possibility of hardware error, but if it works
100% reliably without HT/SMP, but virtually crashes at high load with
Apache, that would pretty much rule out hardware error, unless the CPU's
HT is buggy (highly unlikely).
> Well, its not that the kernel does not detect the ht, it does and quite
> fine (shows lots of processors in the box and all).
>
> The problem is that apache is crashing under high load with a segfault.
> Now, as i understand it, this can be a faulty hardware problem (bad
> memory=segfault) or an actual software problem.
>
> Im not shure, but im having this problem as well with an HT server and
> have not been able to rule out the possibility of a faulty hardware
> thing. Nonetheless, this can also be, for example, an ugly module in
> woodies php4 which are particluarly edgy (xslt for example) under high
> load due to them being in beta stage by the time woody froze.
>
> El mar, 16-12-2003 a las 20:07, Theodore Knab escribió:
> > I am using the 2.4.20 kernel with SMP support on a Hyper-threading
> > Intel. I remember having problems getting it work with SMP support
> > initially.
> >
> > I think the kernel has to be perfect. ;-)
> >
> > Do you have high memory support compiled in ?
> > High memory support above 4GB might cause problems.
> >
> > If you do not have more than 2GB of RAM you should make sure that High
> > memory support is not enabled.
> >
> > Also did you enable hyper-threading in BIOS ?
> > Auto-detect modes might cause problems.
> >
http://publib-b.boulder.ibm.com/Redbooks.nsf/RedbookAbstracts/tips0175.html?Open
> >
> > My system:
> >
> > Linux tedsdesk 2.4.20 #22 SMP Mon Jul 21 14:53:07 EDT 2003 i686
> > GNU/Linux
> >
> > ted@tedsdesk:cat /proc/cpuinfo
> > processor : 0
> > vendor_id : GenuineIntel
> > cpu family : 15
> > model : 1
> > model name : Intel(R) Pentium(R) 4 CPU 1.50GHz
> > stepping : 2
> > cpu MHz : 1495.172
> > cache size : 256 KB
> > fdiv_bug : no
> > hlt_bug : no
> > f00f_bug : no
> > coma_bug : no
> > fpu : yes
> > fpu_exception : yes
> > cpuid level : 2
> > wp : yes
> > flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge
> > mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm
> > bogomips : 2981.88
> >
> > The ht in the flags section tells me hyper threading is being
recognized.
> >
> > On 16/12/03 23:23 +0800, Jason Lim wrote:
> > > Hi All...
> > >
> > > Do you guys know anything about a problem with Intel Hyper-threading
(eg.
> > > on the Intel 2.4Ghz HT-enabled processor) that would cause the load
> > > average to jump to over 200?
> > >
> > > Here is the log line:
> > >
> > > Dec 16 22:48:17 be watchdog[250]: loadavg 203 101 40 is higher than
the
> > > given threshold 200 150 100!
> > >
> > > (then it reboots)
> > >
> > > This happened on the 2.4.22 kernel, and now I tried it with the
2.4.23
> > > kernel, and it has the same problem.
> > >
> > > When the kernel is compiled WITHOUT SMP support, the kernel works
fine,
> > > and it can have uptimes of months without any problem. But when SMP
is
> > > compiled in, and the HT processor is correctly identified (and top
can see
> > > CPU0 and CPU1), then it only takes about an hour or two of operation
> > > before the load average jumps like that. Note that this is with
Debian
> > > woody/stable, and with a clean kernel.org kernel.
> > >
> > > Do you guys know anything about this, or have any ideas where I
should
> > > look? Is there something in Woody that isn't friendly with SMP or
perhaps
> > > Hyper-Threading processors?
> > >
> > > Thanks in advance.
> > >
> > > Sincerely,
> > > Jas
> > >
> > >
> > > --
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listmaster@lists.debian.org
> > >
> >
> > --
> > ------------------------------------------
> > Ted Knab
> > Chester, MD 21619
> > ------------------------------------------
> > 35570707f6274702478656021626f6c6964796f6e602f66602478656
> > 02e6164796f6e60237471647560216e6460276c6f62616c60257e696
> > 4797e2a0
> >
>
>
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