Re: [GIT PULL] cputime: Full dynticks task/cputime accounting v8

[Ingo Molnar]

* Frederic Weisbecker <fweisbec@xxxxxxxxx> wrote:

> Ingo,
> 
> Please pull the new full dynticks cputime accounting code that
> can be found at:
> 
> git://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks.git
>         tags/full-dynticks-cputime-for-mingo
> 
> It's exactly the same tag/HEAD as in my v7. I'm just making a new pull
> request in order to restart a fresh thread like you suggested. The old
> one was filled with a discussion with Steve about what we thought was a bug.
> We concluded it was actually an unavoidable tiny error margin due to how we
> consider the boundary between kernel and user space (tick uses user_mode(regs)
> whereas generic vtime uses context tracking callbacks). The artificial
> testcase we were using was making this margin visible. No big difference
> should be found with real workloads though. So Steve gave his Ack on the pull
> request.
> 
> Then Christoph reported a build error but it doesn't belong to this tree:
> it's about an old version of my full dynticks tree.
> 
> So in the end I see no opposition for this tree to be pulled. If anybody
> has any concern, please raise your hand here.
> 
> Thanks.
> 
> ---
> This implements the cputime accounting on full dynticks CPUs.
> 
> Typical cputime stats infrastructure relies on the timer tick and
> its periodic polling on the CPU to account the amount of time
> spent by the CPUs and the tasks per high level domains such as
> userspace, kernelspace, guest, ...
> 
> Now we are preparing to implement full  dynticks capability on
> Linux for Real Time and HPC users who want full CPU isolation.
> This feature requires a cputime accounting that doesn't depend
> on the timer tick.
> 
> To implement it, this new cputime infrastructure plugs into
> kernel/user/guest boundaries to take snapshots of cputime and
> flush these to the stats when needed. This performs pretty
> much like CONFIG_VIRT_CPU_ACCOUNTING except that context location
> and cputime snaphots are synchronized between write and read
> side such that the latter can safely retrieve the pending tickless
> cputime of a task and add it to its latest cputime snapshot to
> return the correct result to the user.
> 
> Signed-off-by: Frederic Weisbecker <fweisbec@xxxxxxxxx>
> ---
> 
> Frederic Weisbecker (8):
>   context_tracking: Export context state for generic vtime
>   cputime: Librarize per nsecs resolution cputime definitions
>   cputime: Move default nsecs_to_cputime() to jiffies based cputime
>     file
>   cputime: Generic on-demand virtual cputime accounting
>   cputime: Allow dynamic switch between tick/virtual based cputime
>     accounting
>   cputime: Use accessors to read task cputime stats
>   kvm: Prepare to add generic guest entry/exit callbacks
>   cputime: Safely read cputime of full dynticks CPUs
> 
>  arch/alpha/kernel/osf_sys.c                  |    6 +-
>  arch/ia64/include/asm/cputime.h              |   92 +--------
>  arch/ia64/include/asm/thread_info.h          |    4 +-
>  arch/ia64/include/asm/xen/minstate.h         |    2 +-
>  arch/ia64/kernel/asm-offsets.c               |    2 +-
>  arch/ia64/kernel/entry.S                     |   16 +-
>  arch/ia64/kernel/fsys.S                      |    4 +-
>  arch/ia64/kernel/head.S                      |    4 +-
>  arch/ia64/kernel/ivt.S                       |    8 +-
>  arch/ia64/kernel/minstate.h                  |    2 +-
>  arch/ia64/kernel/time.c                      |    5 +-
>  arch/powerpc/configs/chroma_defconfig        |    2 +-
>  arch/powerpc/configs/corenet64_smp_defconfig |    2 +-
>  arch/powerpc/configs/pasemi_defconfig        |    2 +-
>  arch/powerpc/include/asm/cputime.h           |    6 +-
>  arch/powerpc/include/asm/lppaca.h            |    2 +-
>  arch/powerpc/include/asm/ppc_asm.h           |    4 +-
>  arch/powerpc/kernel/entry_64.S               |    4 +-
>  arch/powerpc/kernel/time.c                   |    5 +-
>  arch/powerpc/platforms/pseries/dtl.c         |    6 +-
>  arch/powerpc/platforms/pseries/setup.c       |    6 +-
>  arch/s390/kernel/vtime.c                     |    6 +-
>  arch/x86/kernel/apm_32.c                     |   11 +-
>  drivers/isdn/mISDN/stack.c                   |    7 +-
>  fs/binfmt_elf.c                              |    8 +-
>  fs/binfmt_elf_fdpic.c                        |    7 +-
>  fs/proc/array.c                              |    4 +-
>  include/asm-generic/cputime.h                |   66 +-----
>  include/asm-generic/cputime_jiffies.h        |   72 ++++++
>  include/asm-generic/cputime_nsecs.h          |  104 +++++++++
>  include/linux/context_tracking.h             |   28 +++
>  include/linux/hardirq.h                      |    4 +-
>  include/linux/init_task.h                    |   11 +
>  include/linux/kernel_stat.h                  |    2 +-
>  include/linux/kvm_host.h                     |   55 ++++-
>  include/linux/sched.h                        |   40 ++++
>  include/linux/tsacct_kern.h                  |    3 +
>  include/linux/vtime.h                        |   59 ++++--
>  init/Kconfig                                 |   23 ++-
>  kernel/acct.c                                |    6 +-
>  kernel/context_tracking.c                    |   43 +++--
>  kernel/cpu.c                                 |    4 +-
>  kernel/delayacct.c                           |    7 +-
>  kernel/exit.c                                |   10 +-
>  kernel/fork.c                                |    6 +
>  kernel/posix-cpu-timers.c                    |   28 ++-
>  kernel/sched/core.c                          |    1 +
>  kernel/sched/cputime.c                       |  298 +++++++++++++++++++++++---
>  kernel/signal.c                              |   12 +-
>  kernel/softirq.c                             |    6 +-
>  kernel/time/tick-sched.c                     |    5 +-
>  kernel/tsacct.c                              |   44 +++-
>  52 files changed, 842 insertions(+), 322 deletions(-)
>  create mode 100644 include/asm-generic/cputime_jiffies.h
>  create mode 100644 include/asm-generic/cputime_nsecs.h

Pulled, thanks a lot Frederic!

	Ingo
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