[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [xen master] x86/APIC: no need for timer calibration when using TDT
commit 0731a56c7c72fc117b69982e002954645fc3685b Author: Jan Beulich <jbeulich@xxxxxxxx> AuthorDate: Mon Jan 24 08:38:55 2022 +0100 Commit: Jan Beulich <jbeulich@xxxxxxxx> CommitDate: Mon Jan 24 08:38:55 2022 +0100 x86/APIC: no need for timer calibration when using TDT The only global effect of calibrate_APIC_clock() is the setting of "bus_scale"; the final __setup_APIC_LVTT(0) is (at best) redundant with the immediately following setup_APIC_timer() invocation. Yet "bus_scale" isn't used when using TDT. Avoid wasting 100ms for calibration in this case. Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx> Acked-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx> --- xen/arch/x86/apic.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/xen/arch/x86/apic.c b/xen/arch/x86/apic.c index d7d5c15155..5d3e1f3952 100644 --- a/xen/arch/x86/apic.c +++ b/xen/arch/x86/apic.c @@ -1292,11 +1292,15 @@ void __init setup_boot_APIC_clock(void) check_deadline_errata(); + if ( !boot_cpu_has(X86_FEATURE_TSC_DEADLINE) ) + tdt_enable = false; + local_irq_save(flags); - calibrate_APIC_clock(); + if ( !tdt_enable || apic_verbosity ) + calibrate_APIC_clock(); - if ( tdt_enable && boot_cpu_has(X86_FEATURE_TSC_DEADLINE) ) + if ( tdt_enable ) { printk(KERN_DEBUG "TSC deadline timer enabled\n"); tdt_enabled = true; -- generated by git-patchbot for /home/xen/git/xen.git#master
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