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From: Kyung Min Park <kyung.min.park@intel.com>
To: x86@kernel.org, linux-kernel@vger.kernel.org
Cc: tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com,
	gregkh@linuxfoundation.org, ak@linux.intel.com,
	tony.luck@intel.com, ashok.raj@intel.com,
	ravi.v.shankar@intel.com, fenghua.yu@intel.com
Subject: [PATCH 0/2] x86/delay: Introduce TPAUSE instruction
Date: Wed, 26 Feb 2020 11:10:56 -0800	[thread overview]
Message-ID: <1582744258-42744-1-git-send-email-kyung.min.park@intel.com> (raw)

Intel processors that support the WAITPKG feature implement
the TPAUSE instruction that suspends execution in a lower power
state until the TSC (Time Stamp Counter) exceeds a certain value.

Update the udelay() function to use TPAUSE on systems where it
is available. Note that we hard code the deeper (C0.2) sleep
state because exit latency is small compared to the "microseconds"
that usleep() will delay.

Kyung Min Park (2):
  x86/asm: Define a few helpers in delay_waitx()
  x86/asm/delay: Introduce TPAUSE delay

 arch/x86/include/asm/mwait.h | 17 +++++++++
 arch/x86/lib/delay.c         | 82 ++++++++++++++++++++++++++++++++------------
 2 files changed, 78 insertions(+), 21 deletions(-)

-- 
2.7.4


             reply	other threads:[~2020-02-26 19:11 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-26 19:10 Kyung Min Park [this message]
2020-02-26 19:10 ` [PATCH 1/2] x86/asm: Define a few helpers in delay_waitx() Kyung Min Park
2020-03-18 20:19   ` Thomas Gleixner
2020-02-26 19:10 ` [PATCH 2/2] x86/asm/delay: Introduce TPAUSE delay Kyung Min Park
2020-02-26 21:10   ` Andi Kleen
2020-02-26 21:20     ` Luck, Tony
2020-02-26 21:59       ` Andi Kleen
2020-02-26 21:31     ` Fenghua Yu

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