Messages in this thread | | | Date | Tue, 1 Aug 2006 01:38:26 -0700 | From | Andrew Morton <> | Subject | Re: too low MAX_MP_BUSSES |
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On Mon, 31 Jul 2006 13:55:45 +0200 Vitezslav Samel <samel@mail.cz> wrote:
> Hi! > > I tried upgrading our server (i386 arch) from 2.6.16 to 2.6.17 but there > were some odd messages in dmesg: > > MP table busid value (32) for bustype ISA is too large, max. supported is 31 > > and (repeated 315 times): > > unknown bus type 32 > > I found out that 50% of the processor time was spent in softirq and the timers > ran too fast. I didn't look for what else was wrong. > > Tracked down to this change in 2.6.17-rc2: > > diff -urN linux-2.6.17-rc1/arch/i386/kernel/mpparse.c linux-2.6.17-rc2/arch/i386/kernel/mpparse.c > + if (m->mpc_busid >= MAX_MP_BUSSES) { > + printk(KERN_WARNING "MP table busid value (%d) for bustype %s " > + " is too large, max. supported is %d\n", > + m->mpc_busid, str, MAX_MP_BUSSES - 1); > + return; > + } > > Uping the MAX_MP_BUSSES value in include/asm-i386/mach-default/mach_mpspec.h > to 64 makes the machine work O.K. > The system is HP DL380 g4 with 1 Xeon CPU, kernel compiled non-SMP. > > Here is excerpt from mptable output: > --- > Bus: Bus ID Type > 0 PCI > 1 PCI > 2 PCI > 3 PCI > 4 PCI > 5 PCI > 6 PCI > 10 PCI > 32 ISA > --- > The last item is the offending one. > > Please, can you consider up the default value of MAX_MP_BUSSES? > > P.S.: also tested 2.6.18-rc3, the same - bad - result >
mach-default uses 32 and mach-generic uses 260, so I doubt if there's a big downside to increasing mach-default. I expect distros ship with mach-generic, so you're a rare case.
<tries to remember who works on this and fails>
Andi? Can you see any problems with increasing the mach-default setting?
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