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| author | Thomas Gleixner <tglx@kernel.org> | 2026-02-24 19:36:24 +0300 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2026-02-27 18:40:07 +0300 |
| commit | b27801189f7fc97a960a96a63b78dcabbb67a52f (patch) | |
| tree | e6861b48201942ecdb079230597a8861626c7142 | |
| parent | 2e27beeb66e43f3b84aef5a07e486a5d50695c06 (diff) | |
| download | linux-b27801189f7fc97a960a96a63b78dcabbb67a52f.tar.xz | |
x86: Inline TSC reads in timekeeping
Avoid the overhead of the indirect call for a single instruction to read
the TSC.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260224163429.741886362@kernel.org
| -rw-r--r-- | arch/x86/Kconfig | 1 | ||||
| -rw-r--r-- | arch/x86/include/asm/clock_inlined.h | 14 | ||||
| -rw-r--r-- | arch/x86/kernel/tsc.c | 1 |
3 files changed, 16 insertions, 0 deletions
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index e2df1b147184..d337d8dced86 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -141,6 +141,7 @@ config X86 select ARCH_USE_SYM_ANNOTATIONS select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH select ARCH_WANT_DEFAULT_BPF_JIT if X86_64 + select ARCH_WANTS_CLOCKSOURCE_READ_INLINE if X86_64 select ARCH_WANTS_DYNAMIC_TASK_STRUCT select ARCH_WANTS_NO_INSTR select ARCH_WANT_GENERAL_HUGETLB diff --git a/arch/x86/include/asm/clock_inlined.h b/arch/x86/include/asm/clock_inlined.h new file mode 100644 index 000000000000..29902c5bcc5c --- /dev/null +++ b/arch/x86/include/asm/clock_inlined.h @@ -0,0 +1,14 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _ASM_X86_CLOCK_INLINED_H +#define _ASM_X86_CLOCK_INLINED_H + +#include <asm/tsc.h> + +struct clocksource; + +static __always_inline u64 arch_inlined_clocksource_read(struct clocksource *cs) +{ + return (u64)rdtsc_ordered(); +} + +#endif diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c index d9aa694e43f3..74a26fb4417c 100644 --- a/arch/x86/kernel/tsc.c +++ b/arch/x86/kernel/tsc.c @@ -1201,6 +1201,7 @@ static struct clocksource clocksource_tsc = { .mask = CLOCKSOURCE_MASK(64), .flags = CLOCK_SOURCE_IS_CONTINUOUS | CLOCK_SOURCE_VALID_FOR_HRES | + CLOCK_SOURCE_CAN_INLINE_READ | CLOCK_SOURCE_MUST_VERIFY | CLOCK_SOURCE_VERIFY_PERCPU, .id = CSID_X86_TSC, |