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| author | John Stultz <john.stultz@linaro.org> | 2010-12-03 01:47:52 +0100 |
|---|---|---|
| committer | John Stultz <john.stultz@linaro.org> | 2010-12-03 01:47:52 +0100 |
| commit | b0f969009f647cd473c5e559aeec9c4229d12f87 (patch) | |
| tree | 34778ededa7623d811be4ac143a098a5dc11eed5 | |
| parent | Linux 2.6.37-rc3 (diff) | |
| parent | x86: Make tsc=reliable override boot time stability checks (diff) | |
| download | linux-b0f969009f647cd473c5e559aeec9c4229d12f87.tar.xz linux-b0f969009f647cd473c5e559aeec9c4229d12f87.zip | |
Merge remote branch 'tip/x86/tsc' into fortglx/2.6.38/tip/x86/tsc
Conflicts:
Documentation/kernel-parameters.txt
| -rw-r--r-- | Documentation/kernel-parameters.txt | 9 | ||||
| -rw-r--r-- | arch/x86/kernel/tsc.c | 7 |
2 files changed, 10 insertions, 6 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 92e83e53148f..c7c8eca5b2b3 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -2467,12 +2467,13 @@ and is between 256 and 4096 characters. It is defined in the file to facilitate early boot debugging. See also Documentation/trace/events.txt - tsc= Disable clocksource-must-verify flag for TSC. + tsc= Disable clocksource stability checks for TSC. Format: <string> [x86] reliable: mark tsc clocksource as reliable, this - disables clocksource verification at runtime. - Used to enable high-resolution timer mode on older - hardware, and in virtualized environment. + disables clocksource verification at runtime, as well + as the stability checks done at bootup. Used to enable + high-resolution timer mode on older hardware, and in + virtualized environment. [x86] noirqtime: Do not use TSC to do irq accounting. Used to run time disable IRQ_TIME_ACCOUNTING on any platforms where RDTSC is slow and this accounting diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c index 0c40d8b72416..bb64beb301d9 100644 --- a/arch/x86/kernel/tsc.c +++ b/arch/x86/kernel/tsc.c @@ -872,6 +872,9 @@ __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: @@ -879,10 +882,10 @@ __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) |