From: Fenghua Yu <fenghua.yu@intel.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
H Peter Anvin <hpa@zytor.com>, Andy Lutomirski <luto@kernel.org>,
Ashok Raj <ashok.raj@intel.com>, Tony Luck <tony.luck@intel.com>,
Ravi V Shankar <ravi.v.shankar@intel.com>,
linux-kernel <linux-kernel@vger.kernel.org>, x86 <x86@kernel.org>
Subject: Re: [PATCH v4 2/5] x86/umwait: Initialize umwait control values
Date: Tue, 11 Jun 2019 10:04:02 -0700 [thread overview]
Message-ID: <20190611170402.GA180343@romley-ivt3.sc.intel.com> (raw)
In-Reply-To: <20190611085036.GS3436@hirez.programming.kicks-ass.net>
On Tue, Jun 11, 2019 at 10:50:36AM +0200, Peter Zijlstra wrote:
> On Fri, Jun 07, 2019 at 03:00:34PM -0700, Fenghua Yu wrote:
> > umwait or tpause allows processor to enter a light-weight
> > power/performance optimized state (C0.1 state) or an improved
> > power/performance optimized state (C0.2 state) for a period
> > specified by the instruction or until the system time limit or until
> > a store to the monitored address range in umwait.
> >
> > IA32_UMWAIT_CONTROL MSR register allows kernel to enable/disable C0.2
> > on the processor and set maximum time the processor can reside in
> > C0.1 or C0.2.
> >
> > By default C0.2 is enabled so the user wait instructions can enter the
> > C0.2 state to save more power with slower wakeup time.
> >
> > Default maximum umwait time is 100000 cycles. A later patch provides
> > a sysfs interface to adjust this value.
> >
> > Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
> > Reviewed-by: Ashok Raj <ashok.raj@intel.com>
> > Reviewed-by: Andy Lutomirski <luto@kernel.org>
> > ---
> > arch/x86/include/asm/msr-index.h | 4 +++
> > arch/x86/power/Makefile | 1 +
> > arch/x86/power/umwait.c | 56 ++++++++++++++++++++++++++++++++
>
> Why is this in power/, this isn't in the least related to
> suspend/hybernate. arch/x86/kernel/cpu/ might be a better place for
> instruction support.
Ok. I can move umwait.c to arch/x86/kernel/cpu/umwait.c.
Thanks.
-Fenghua
next prev parent reply other threads:[~2019-06-11 17:13 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-07 22:00 [PATCH v4 0/5] x86/umwait: Enable user wait instructions Fenghua Yu
2019-06-07 22:00 ` [PATCH v4 1/5] x86/cpufeatures: Enumerate " Fenghua Yu
2019-06-07 22:00 ` [PATCH v4 2/5] x86/umwait: Initialize umwait control values Fenghua Yu
2019-06-08 22:52 ` Andy Lutomirski
2019-06-10 4:13 ` Fenghua Yu
2019-06-10 4:27 ` Andy Lutomirski
2019-06-11 20:46 ` Thomas Gleixner
2019-06-17 20:46 ` Fenghua Yu
2019-06-18 5:43 ` Thomas Gleixner
2019-06-11 8:50 ` Peter Zijlstra
2019-06-11 17:04 ` Fenghua Yu [this message]
2019-06-07 22:00 ` [PATCH v4 3/5] x86/umwait: Add sysfs interface to control umwait C0.2 state Fenghua Yu
2019-06-08 22:50 ` Andy Lutomirski
2019-06-10 3:53 ` Fenghua Yu
2019-06-10 4:24 ` Andy Lutomirski
2019-06-10 6:02 ` Fenghua Yu
2019-06-10 13:41 ` Andy Lutomirski
2019-06-17 20:27 ` Fenghua Yu
2019-06-17 23:02 ` Andy Lutomirski
2019-06-17 23:11 ` Fenghua Yu
2019-06-17 23:41 ` Andy Lutomirski
2019-06-18 0:00 ` Fenghua Yu
2019-06-18 0:19 ` Andy Lutomirski
2019-06-18 2:32 ` Fenghua Yu
2019-06-08 22:52 ` Andy Lutomirski
2019-06-10 4:04 ` Fenghua Yu
2019-06-10 4:26 ` Andy Lutomirski
2019-06-17 22:48 ` Fenghua Yu
2019-06-17 22:59 ` Andy Lutomirski
2019-06-17 22:51 ` Fenghua Yu
2019-06-11 8:54 ` Peter Zijlstra
2019-06-11 16:04 ` Andy Lutomirski
2019-06-11 17:27 ` Peter Zijlstra
2019-06-17 15:14 ` Andy Lutomirski
2019-06-17 18:11 ` Fenghua Yu
2019-06-07 22:00 ` [PATCH v4 4/5] x86/umwait: Add sysfs interface to control umwait maximum time Fenghua Yu
2019-06-07 22:00 ` [PATCH v4 5/5] x86/umwait: Document umwait control sysfs interfaces Fenghua Yu
2019-06-11 9:01 ` [PATCH v4 0/5] x86/umwait: Enable user wait instructions Peter Zijlstra
2019-06-11 17:37 ` Fenghua Yu
2019-06-17 14:19 ` Peter Zijlstra
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