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| author | Kyung Min Park <kyung.min.park@intel.com> | 2020-04-24 12:37:56 -0700 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2020-05-07 16:06:20 +0200 |
| commit | cec5f268cd02d25d2d74807843d8ae0292fe0fb7 (patch) | |
| tree | 917947f6e242b5f1c21e136cf3916dd09c3473ce /arch/x86/include/asm/delay.h | |
| parent | 46f90c7aad62be1af76588108c730d826308a801 (diff) | |
| download | linux-stable-cec5f268cd02d25d2d74807843d8ae0292fe0fb7.tar.gz linux-stable-cec5f268cd02d25d2d74807843d8ae0292fe0fb7.tar.bz2 linux-stable-cec5f268cd02d25d2d74807843d8ae0292fe0fb7.zip | |
x86/delay: Introduce TPAUSE delay
TPAUSE instructs the processor to enter an implementation-dependent
optimized state. The instruction execution wakes up when the time-stamp
counter reaches or exceeds the implicit EDX:EAX 64-bit input value.
The instruction execution also wakes up due to the expiration of
the operating system time-limit or by an external interrupt
or exceptions such as a debug exception or a machine check exception.
TPAUSE offers a choice of two lower power states:
1. Light-weight power/performance optimized state C0.1
2. Improved power/performance optimized state C0.2
This way, it can save power with low wake-up latency in comparison to
spinloop based delay. The selection between the two is governed by the
input register.
TPAUSE is available on processors with X86_FEATURE_WAITPKG.
Co-developed-by: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Kyung Min Park <kyung.min.park@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Link: https://lkml.kernel.org/r/1587757076-30337-4-git-send-email-kyung.min.park@intel.com
Diffstat (limited to 'arch/x86/include/asm/delay.h')
| -rw-r--r-- | arch/x86/include/asm/delay.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/x86/include/asm/delay.h b/arch/x86/include/asm/delay.h index 9aa38de7bd72..630891d25819 100644 --- a/arch/x86/include/asm/delay.h +++ b/arch/x86/include/asm/delay.h @@ -6,6 +6,7 @@ #include <linux/init.h> void __init use_tsc_delay(void); +void __init use_tpause_delay(void); void use_mwaitx_delay(void); #endif /* _ASM_X86_DELAY_H */ |