Messages in this thread | | | From | Huang Rui <> | Subject | [PATCH v5 0/2] x86, mwaitt: introduce AMD mwaitt support | Date | Mon, 15 Jun 2015 18:48:02 +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.
Changes from v2 -> v3 - Add compared data on commit message - Remove kernel parameter - Add hint to avoid to access deep state in future - Update mwaitx delay method as Petter's suggestion
Changes from v3 -> v4 - Put the MONITORX/MWAITX description into comments
Changes from v4 -> v5 - Remove mwaitx function - Use mwaitx_delay at init_amd - Use cpu_tts as montioring address scope
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 (2): x86, mwaitt: add monitorx and mwaitx instruction x86, mwaitt: introduce mwaix delay with a configurable timer
arch/x86/include/asm/cpufeature.h | 1 + arch/x86/include/asm/delay.h | 1 + arch/x86/include/asm/mwait.h | 43 +++++++++++++++++++++++++++++++++++++ arch/x86/kernel/cpu/amd.c | 4 ++++ arch/x86/lib/delay.c | 45 +++++++++++++++++++++++++++++++++++++++ 5 files changed, 94 insertions(+)
-- 1.9.1
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