• Frederic Weisbecker's avatar
    cputime: Allow dynamic switch between tick/virtual based cputime accounting · 3f4724ea
    Frederic Weisbecker authored
    Allow to dynamically switch between tick and virtual based
    cputime accounting. This way we can provide a kind of "on-demand"
    virtual based cputime accounting. In this mode, the kernel relies
    on the context tracking subsystem to dynamically probe on kernel
    boundaries.
    
    This is in preparation for being able to stop the timer tick in
    more places than just the idle state. Doing so will depend on
    CONFIG_VIRT_CPU_ACCOUNTING_GEN which makes it possible to account
    the cputime without the tick by hooking on kernel/user boundaries.
    
    Depending whether the tick is stopped or not, we can switch between
    tick and vtime based accounting anytime in order to minimize the
    overhead associated to user hooks.
    Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
    Cc: Andrew Morton <akpm@linux-foundation.org>
    Cc: Ingo Molnar <mingo@kernel.org>
    Cc: Li Zhong <zhong@linux.vnet.ibm.com>
    Cc: Namhyung Kim <namhyung.kim@lge.com>
    Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
    Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Cc: Steven Rostedt <rostedt@goodmis.org>
    Cc: Thomas Gleixner <tglx@linutronix.de>
    3f4724ea
tick-sched.c 23.6 KB