From: Fenghua Yu <fenghua.yu@intel.com>
To: "Thomas Gleixner" <tglx@linutronix.de>,
"Ingo Molnar" <mingo@redhat.com>,
"Borislav Petkov" <bp@alien8.de>, "H Peter Anvin" <hpa@zytor.com>,
"Andy Lutomirski" <luto@amacapital.net>,
"Andrew Cooper" <andrew.cooper3@citrix.com>,
"Ashok Raj" <ashok.raj@intel.com>,
"Tony Luck" <tony.luck@intel.com>,
"Ravi V Shankar" <ravi.v.shankar@intel.com>
Cc: "linux-kernel" <linux-kernel@vger.kernel.org>,
"x86" <x86@kernel.org>, Fenghua Yu <fenghua.yu@intel.com>
Subject: [PATCH v3 5/5] x86/umwait: Document umwait control sysfs interfaces
Date: Fri, 24 May 2019 16:56:02 -0700 [thread overview]
Message-ID: <1558742162-73402-6-git-send-email-fenghua.yu@intel.com> (raw)
In-Reply-To: <1558742162-73402-1-git-send-email-fenghua.yu@intel.com>
Since two new sysfs interface files are created for umwait control, add
an ABI document entry for the files:
/sys/devices/system/cpu/umwait_control/enable_c0_2
/sys/devices/system/cpu/umwait_control/max_time
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Reviewed-by: Ashok Raj <ashok.raj@intel.com>
---
.../ABI/testing/sysfs-devices-system-cpu | 21 +++++++++++++++++++
1 file changed, 21 insertions(+)
diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu
index 1528239f69b2..bbf65ae447ff 100644
--- a/Documentation/ABI/testing/sysfs-devices-system-cpu
+++ b/Documentation/ABI/testing/sysfs-devices-system-cpu
@@ -538,3 +538,24 @@ Description: Intel Energy and Performance Bias Hint (EPB)
This attribute is present for all online CPUs supporting the
Intel EPB feature.
+
+What: /sys/devices/system/cpu/umwait_control
+ /sys/devices/system/cpu/umwait_control/enable_c0_2
+ /sys/devices/system/cpu/umwait_control/max_time
+Date: May 2019
+Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org>
+Description: Umwait control
+
+ enable_c0_2: Read/write interface to control umwait C0.2 state
+ Read returns C0.2 state status:
+ 0: C0.2 is disabled
+ 1: C0.2 is enabled
+
+ Write 'Yy1' or [oO][nN] for on to enable C0.2 state.
+ Write 'Nn0' or [oO][fF] for off to disable C0.2 state.
+
+ max_time: Read/write interface to control umwait maximum time
+ in TSC-quanta that the CPU can reside in either C0.1
+ or C0.2 state. The time is represented as an unsigned
+ integer decimal value. Bits[1:0] are ignore.
+ A zero value indicates no maximum time.
--
2.19.1
prev parent reply other threads:[~2019-05-25 0:05 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-24 23:55 [PATCH v3 0/5] x86/umwait: Enable user wait instructions Fenghua Yu
2019-05-24 23:55 ` [PATCH v3 1/5] x86/cpufeatures: Enumerate " Fenghua Yu
2019-05-30 14:37 ` Andy Lutomirski
2019-05-24 23:55 ` [PATCH v3 2/5] x86/umwait: Initialize umwait control values Fenghua Yu
2019-05-30 21:05 ` Andy Lutomirski
2019-05-24 23:56 ` [PATCH v3 3/5] x86/umwait: Add sysfs interface to control umwait C0.2 state Fenghua Yu
2019-05-30 21:10 ` Andy Lutomirski
2019-05-31 1:17 ` Yu, Fenghua
2019-05-24 23:56 ` [PATCH v3 4/5] x86/umwait: Add sysfs interface to control umwait maximum time Fenghua Yu
2019-05-30 21:11 ` Andy Lutomirski
2019-05-24 23:56 ` Fenghua Yu [this message]
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