| From: |
| Huang Rui <ray.huang@amd.com> |
| To: |
| Borislav Petkov <bp@suse.de>, Andy Lutomirski <luto@amacapital.net>, Thomas Gleixner <tglx@linutronix.de>, Peter Zijlstra <peterz@infradead.org>, "Rafael J. Wysocki" <rjw@rjwysocki.net>, Len Brown <lenb@kernel.org>, "John Stultz" <john.stultz@linaro.org>, Frédéric Weisbecker <fweisbec@gmail.com> |
| Subject: |
| [PATCH v2 0/4] x86, mwaitt: introduce AMD mwaitt support |
| Date: |
| Tue, 9 Jun 2015 11:13:37 +0800 |
| Message-ID: |
| <1433819621-15093-1-git-send-email-ray.huang@amd.com> |
| Cc: |
| <linux-kernel@vger.kernel.org>, <x86@kernel.org>, Fengguang Wu <fengguang.wu@intel.com>, Aaron Lu <aaron.lu@intel.com>, Suravee Suthikulanit <suravee.suthikulpanit@amd.com>, Tony Li <tony.li@amd.com>, Ken Xue <ken.xue@amd.com>, Huang Rui <ray.huang@amd.com> |
| Archive‑link: | |
Article |
Hi,
This patch set introduces a new instruction support on AMD Carrizo (Family
15h, Model 60h-6fh). It adds mwaitx delay function with a configurable
timer.
Andy and Boris provide a suggestion which use mwaitx on delay method.
Some discussions of the background, please see:
http://marc.info/?l=linux-kernel&m=143202042530498&...
http://marc.info/?l=linux-kernel&m=143161327003541&...
http://marc.info/?l=linux-kernel&m=143222815331016&...
They are rebased on tip/master.
Changes from v1 -> v2
- Remove mwaitx idle implementation since some disputes without power
improvement.
- Add a patch which implement another use case on delay.
- Introduce a kernel parameter (delay) to make delay method configurable.
I already do some testing with mwaitx on udelay.
Test scenario:
glb_loops = usec_to_tsc(delay_usec)
rdtsc -> read TSC counters as start
mwaitx_delay(glb_loops)
rdtsc -> read TSC counters as end
diff = end - start
Compared the real TSC counts (diff), that means the loops of counter goes.
And glb_loops is the input value of the EBX, that is the expect loops which
user configures. Below is 10000 us of mwaitx delay, we could see about 1200
(diff - glb_loops) delayed with mwaitx.
[ 2369.008651] start=4401974718758, end=4401992576888, diff=17858130, glb_loops=17856939
Thanks,
Rui
Huang Rui (4):
x86, mwaitt: add monitorx and mwaitx instruction
x86, mwaitt: make delay method configurable
x86, mwaitt: introduce mwaix delay with a configurable timer
x86, mwaitt: add documents of delay option
Documentation/kernel-parameters.txt | 7 ++++++
arch/x86/include/asm/cpufeature.h | 1 +
arch/x86/include/asm/delay.h | 8 ++++++
arch/x86/include/asm/mwait.h | 26 ++++++++++++++++++++
arch/x86/kernel/setup.c | 22 +++++++++++++++++
arch/x86/lib/delay.c | 46 +++++++++++++++++++++++++++++++++--
6 files changed, 108 insertions(+), 2 deletions(-)
--
1.7.9.5
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