Messages in this thread | | | From | Huang Rui <> | Subject | [PATCH v2 0/4] x86, mwaitt: introduce AMD mwaitt support | Date | Tue, 9 Jun 2015 11:13:37 +0800 |
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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&w=2 http://marc.info/?l=linux-kernel&m=143161327003541&w=2 http://marc.info/?l=linux-kernel&m=143222815331016&w=2
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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