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 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/mwait.h | 27 ++++++++++++++++++++++++++ arch/x86/lib/delay.c | 41 ++++++++++++++++++++++++++++++++++++++- 3 files changed, 68 insertions(+), 1 deletion(-) -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
