From: Andi Kleen <ak@linux.intel.com>
To: "Luck, Tony" <tony.luck@intel.com>
Cc: Kyung Min Park <kyung.min.park@intel.com>,
x86@kernel.org, linux-kernel@vger.kernel.org, tglx@linutronix.de,
mingo@redhat.com, hpa@zytor.com, gregkh@linuxfoundation.org,
ashok.raj@intel.com, ravi.v.shankar@intel.com,
fenghua.yu@intel.com
Subject: Re: [PATCH 2/2] x86/asm/delay: Introduce TPAUSE delay
Date: Wed, 26 Feb 2020 13:59:28 -0800 [thread overview]
Message-ID: <20200226215928.GU160988@tassilo.jf.intel.com> (raw)
In-Reply-To: <20200226212034.GA21102@agluck-desk2.amr.corp.intel.com>
On Wed, Feb 26, 2020 at 01:20:34PM -0800, Luck, Tony wrote:
> On Wed, Feb 26, 2020 at 01:10:40PM -0800, Andi Kleen wrote:
> > On Wed, Feb 26, 2020 at 11:10:58AM -0800, Kyung Min Park wrote:
> > > 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
> >
> > This is actually a behavior change. Today's udelay() will continue
> > after processing the interrupt. Your patches don't
>
> The instruction level TPAUSE is called inside delay_wait()
> that checks to see of we were interrupted early and loops to issue
> another TPAUSE if needed.
Ah right. It was already solved for mwaitx. Great.
-Andi
next prev parent reply other threads:[~2020-02-26 21:59 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-26 19:10 [PATCH 0/2] x86/delay: Introduce TPAUSE instruction Kyung Min Park
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 [this message]
2020-02-26 21:31 ` Fenghua Yu
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