Hi, Here is an update to the getcpu_cache system call following the v2 round of review. It implements a cache for the CPU number of the currently running thread in user-space. Benchmarks comparing this approach to a getcpu based on system call on ARM show a 44x speedup. They show a 14x speedup on x86-64 compared to executing lsl from a vDSO through glibc. This patchset is sent as RFC. It applies on Linux 4.4. It is submitted for feedback. I'm targeting the 4.6 merge window. Feedback is welcome, Thanks! Mathieu Mathieu Desnoyers (5): getcpu_cache system call: cache CPU number of running thread getcpu_cache: ARM resume notifier getcpu_cache: wire up ARM system call getcpu_cache: x86 32/64 resume notifier getcpu_cache: wire up x86 32/64 system call MAINTAINERS | 7 ++ arch/arm/include/uapi/asm/unistd.h | 1 + arch/arm/kernel/calls.S | 1 + arch/arm/kernel/signal.c | 1 + arch/x86/entry/common.c | 1 + arch/x86/entry/syscalls/syscall_32.tbl | 1 + arch/x86/entry/syscalls/syscall_64.tbl | 1 + fs/exec.c | 1 + include/linux/sched.h | 36 ++++++++ include/uapi/linux/Kbuild | 1 + include/uapi/linux/getcpu_cache.h | 42 +++++++++ init/Kconfig | 10 +++ kernel/Makefile | 1 + kernel/fork.c | 4 + kernel/getcpu_cache.c | 150 +++++++++++++++++++++++++++++++++ kernel/sched/sched.h | 1 + kernel/sys_ni.c | 3 + 17 files changed, 262 insertions(+) create mode 100644 include/uapi/linux/getcpu_cache.h create mode 100644 kernel/getcpu_cache.c -- 2.1.4 -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
