Messages in this thread Patch in this message | | | From | Feng Tang <> | Subject | [PATCH v1 2/2] x86/tsc: Extend watchdog check exemption to 4-Sockets platform | Date | Fri, 21 Oct 2022 14:21:31 +0800 |
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There is report again that the tsc clocksource on a 4 sockets x86 Skylake server was wrongly judged as 'unstable' by 'jiffies' watchdog, and disabled [1].
Commit b50db7095fe0 ("x86/tsc: Disable clocksource watchdog for TSC on qualified platorms") was introduce to deal with these false alarms of tsc unstable issues, covering qualified platforms for 2 sockets or smaller ones.
Extend the exemption to 4 sockets to fix the issue.
We also got similar reports on 8 sockets platform from internal test, but as Peter pointed out, there was tsc sync issues for 8-sockets platform, and it'd better be handled architecture by architecture, instead of directly changing the threshold to 8 here.
Rui also proposed another way to disable 'jiffies' as clocksource watchdog [2], which can also solve this specific problem in an architecture independent way, with one limitation that there are also some tsc false alarms which were reported by other hardware watchdogs like HPET/PMTIMER, while 'jiffies' watchdog is mostly used in kernel boot phase.
[1]. https://lore.kernel.org/all/9d3bf570-3108-0336-9c52-9bee15767d29@huawei.com/ [2]. https://lore.kernel.org/all/bd5b97f89ab2887543fc262348d1c7cafcaae536.camel@intel.com/
Reported-by: Yu Liao <liaoyu15@huawei.com> Signed-off-by: Feng Tang <feng.tang@intel.com> --- arch/x86/kernel/tsc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c index 178448ef00c7..356f06287034 100644 --- a/arch/x86/kernel/tsc.c +++ b/arch/x86/kernel/tsc.c @@ -1400,7 +1400,7 @@ static int __init init_tsc_clocksource(void) if (boot_cpu_has(X86_FEATURE_CONSTANT_TSC) && boot_cpu_has(X86_FEATURE_NONSTOP_TSC) && boot_cpu_has(X86_FEATURE_TSC_ADJUST) && - logical_packages <= 2) + logical_packages <= 4) clocksource_tsc.flags &= ~CLOCK_SOURCE_MUST_VERIFY; /* -- 2.34.1
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