Messages in this thread Patch in this message | | | Subject | Re: clocksource changes in 2.6.31 - possible regression | From | john stultz <> | Date | Mon, 17 Aug 2009 15:23:22 -0700 |
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On Mon, 2009-08-17 at 14:45 -0700, Stephen Hemminger wrote: > On Mon, 17 Aug 2009 14:37:57 -0700 > john stultz <johnstul@us.ibm.com> wrote: > > However, I think its fair, that as your TSC is being disqualified for > > being an old AMD SMP box, and there is a *possibility* that if you don't > > run with cpufreq and the SUMA-ness of the box didn't get in the way of > > TSC synchronization, you might have an argument for overriding the > > unsynchronized_tsc() heuristics. > > > > Luckily the option is already there. :) > > > > So try booting with "tsc=reliable" to override those checks, and I think > > you'll be able to do what you want to do. > > > > Good idea, doesn't work. > > vyatta@amd1:~$ cat /proc/cmdline > BOOT_IMAGE=/boot/vmlinuz-2.6.31-rc6 root=/dev/sda1 ro tsc=reliable > vyatta@amd1:~$ cat /sys/devices/system/clocksource/clocksource0/available_clocksource > acpi_pm
Bah! My apologies for half-assing this.
How about with the following *tested* patch (includes a variant of Thomas' fix).
thanks -john
Signed-off-by: John Stultz <johnstul@us.ibm.com>
diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c index 71f4368..648fb26 100644 --- a/arch/x86/kernel/tsc.c +++ b/arch/x86/kernel/tsc.c @@ -825,6 +825,9 @@ __cpuinit int unsynchronized_tsc(void) if (boot_cpu_has(X86_FEATURE_CONSTANT_TSC)) return 0; + + if (tsc_clocksource_reliable) + return 0; /* * Intel systems are normally all synchronized. * Exceptions must mark TSC as unstable: @@ -832,10 +835,10 @@ __cpuinit int unsynchronized_tsc(void) if (boot_cpu_data.x86_vendor != X86_VENDOR_INTEL) { /* assume multi socket systems are not synchronized: */ if (num_possible_cpus() > 1) - tsc_unstable = 1; + return 1; } - return tsc_unstable; + return 0; } static void __init init_tsc_clocksource(void)
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