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Message-ID: <20130205121336.GB21455@gmail.com>
Date: Tue, 5 Feb 2013 13:13:36 +0100
From: Ingo Molnar <mingo@...nel.org>
To: Frederic Weisbecker <fweisbec@...il.com>
Cc: LKML <linux-kernel@...r.kernel.org>,
Andrew Morton <akpm@...ux-foundation.org>,
Li Zhong <zhong@...ux.vnet.ibm.com>,
Namhyung Kim <namhyung.kim@....com>,
"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>,
Paul Gortmaker <paul.gortmaker@...driver.com>,
Peter Zijlstra <peterz@...radead.org>,
Steven Rostedt <rostedt@...dmis.org>,
Thomas Gleixner <tglx@...utronix.de>,
Sedat Dilek <sedat.dilek@...il.com>,
Gleb Natapov <gleb@...hat.com>,
Marcelo Tosatti <mtosatti@...hat.com>,
Tony Luck <tony.luck@...el.com>,
Fenghua Yu <fenghua.yu@...el.com>,
Christoph Lameter <cl@...ux.com>
Subject: Re: [GIT PULL] cputime: Full dynticks task/cputime accounting v8
* Frederic Weisbecker <fweisbec@...il.com> 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@...il.com>
> ---
>
> 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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