Groups > linux.kernel > #1319157

[RFC PATCH v2 0/3] getcpu_cache system call

From	Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Newsgroups	linux.kernel
Subject	[RFC PATCH v2 0/3] getcpu_cache system call
Date	2016-01-27 18:00 +0100
Message-ID	<qVBBL-6sQ-3@gated-at.bofh.it> (permalink)
Organization	linux.* mail to news gateway

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Hi,

Here is a patchset implementing 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.

I'm added a man page in the changelog of patch 1/3, which shows an
example usage of this new system call.

This patchset is sent as RFC. It applies on Linux 4.4.

Feedback is welcome,

Thanks!

Mathieu


Mathieu Desnoyers (3):
  getcpu_cache system call: cache CPU number of running thread
  getcpu_cache: wire up ARM system call
  getcpu_cache: wire up x86 32/64 system call

 MAINTAINERS                            |   6 ++
 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 +++++++++++
 init/Kconfig                           |  10 ++++
 kernel/Makefile                        |   1 +
 kernel/fork.c                          |   4 ++
 kernel/getcpu_cache.c                  | 106 +++++++++++++++++++++++++++++++++
 kernel/sched/sched.h                   |   1 +
 kernel/sys_ni.c                        |   3 +
 15 files changed, 174 insertions(+)
 create mode 100644 kernel/getcpu_cache.c

-- 
2.1.4

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[RFC PATCH v2 0/3] getcpu_cache system call Mathieu Desnoyers <mathieu.desnoyers@efficios.com> - 2016-01-27 18:00 +0100
  [RFC PATCH v2 3/3] getcpu_cache: wire up x86 32/64 system call Mathieu Desnoyers <mathieu.desnoyers@efficios.com> - 2016-01-27 18:00 +0100
  [RFC PATCH v2 1/3] getcpu_cache system call: cache CPU number of running thread Mathieu Desnoyers <mathieu.desnoyers@efficios.com> - 2016-01-27 18:00 +0100
    Re: [RFC PATCH v2 1/3] getcpu_cache system call: cache CPU number  of running thread Thomas Gleixner <tglx@linutronix.de> - 2016-01-27 18:30 +0100
      Re: [RFC PATCH v2 1/3] getcpu_cache system call: cache CPU number  of running thread Mathieu Desnoyers <mathieu.desnoyers@efficios.com> - 2016-01-27 18:40 +0100
        Re: [RFC PATCH v2 1/3] getcpu_cache system call: cache CPU number of  running thread Josh Triplett <josh@joshtriplett.org> - 2016-01-27 19:10 +0100
          Re: [RFC PATCH v2 1/3] getcpu_cache system call: cache CPU number  of running thread Mathieu Desnoyers <mathieu.desnoyers@efficios.com> - 2016-01-27 19:50 +0100
            Re: [RFC PATCH v2 1/3] getcpu_cache system call: cache CPU number of  running thread Josh Triplett <josh@joshtriplett.org> - 2016-01-27 20:40 +0100
              Re: [RFC PATCH v2 1/3] getcpu_cache system call: cache CPU number  of running thread Mathieu Desnoyers <mathieu.desnoyers@efficios.com> - 2016-01-27 22:10 +0100
                Re: [RFC PATCH v2 1/3] getcpu_cache system call: cache CPU number of  running thread Josh Triplett <josh@joshtriplett.org> - 2016-01-27 22:40 +0100
        Re: [RFC PATCH v2 1/3] getcpu_cache system call: cache CPU number of  running thread Andrew Hunter <ahh@google.com> - 2016-01-27 19:10 +0100
    Re: [RFC PATCH v2 1/3] getcpu_cache system call: cache CPU number  of running thread Thomas Gleixner <tglx@linutronix.de> - 2016-01-27 18:30 +0100
      Re: [RFC PATCH v2 1/3] getcpu_cache system call: cache CPU number  of running thread Thomas Gleixner <tglx@linutronix.de> - 2016-01-27 18:40 +0100
        Re: [RFC PATCH v2 1/3] getcpu_cache system call: cache CPU number  of running thread Mathieu Desnoyers <mathieu.desnoyers@efficios.com> - 2016-01-27 22:40 +0100
      Re: [RFC PATCH v2 1/3] getcpu_cache system call: cache CPU number  of running thread Thomas Gleixner <tglx@linutronix.de> - 2016-01-27 18:40 +0100
      Re: [RFC PATCH v2 1/3] getcpu_cache system call: cache CPU number  of running thread Mathieu Desnoyers <mathieu.desnoyers@efficios.com> - 2016-01-27 18:40 +0100
    Re: [RFC PATCH v2 1/3] getcpu_cache system call: cache CPU number of  running thread Josh Triplett <josh@joshtriplett.org> - 2016-01-27 18:30 +0100

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