vtime: Delay cputime accounting to tick / context switch
Ingo, Thomas,
Please pull the vtime/accumulate-for-tip branch that can be found at:
git://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks.git
vtime/accumulate-for-tip
HEAD: 0fe66425659da25269280c106f39b333a0cfb9a9
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The cputime accounting functions (account_system_time(), account_user_time(), ...) happen to be costly especially under several common configs. And with CONFIG_VIRT_CPU_ACCOUNTING_NATIVE those functions are called on many fast paths such as context boundaries like user <-> kernel, kernel <-> guest, kernel <-> idle, kernel <-> (soft)IRQ, context switches, etc...
This set reduces this overhead by accumulating the cputime on context boundaries and eventually delay the accounting of that accumulated time on ticks and context switches only.
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Thanks,
Frederic
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Frederic Weisbecker (9):
powerpc32: Fix stale scaled stime on context switch
ia64: Fix wrong start cputime assignment on task switch
cputime: Allow accounting system time using cpustat index
cputime: Export account_guest_time
powerpc: Prepare accounting structure for cputime flush on tick
powerpc: Migrate stolen_time field to accounting structure powerpc/vtime: Accumulate cputime and account only on tick/task switch
ia64: Accumulate cputime and account only on tick/task switch
vtime: Rename vtime_account_user() to vtime_flush()
Martin Schwidefsky (1):
s390/cputime: Delayed accounting of system time
arch/ia64/include/asm/thread_info.h | 6 ++ arch/ia64/kernel/time.c | 66 +++++++++++----- arch/powerpc/include/asm/accounting.h | 14 +++- arch/powerpc/include/asm/paca.h | 1 - arch/powerpc/kernel/asm-offsets.c | 8 +- arch/powerpc/kernel/time.c | 138 +++++++++++++++++++++------------- arch/powerpc/xmon/xmon.c | 8 +- arch/s390/include/asm/lowcore.h | 65 ++++++++-------- arch/s390/include/asm/processor.h | 3 + arch/s390/kernel/vtime.c | 138 ++++++++++++++++++++++------------ include/linux/kernel_stat.h | 5 +- include/linux/vtime.h | 7 +- kernel/sched/cputime.c | 16 ++-- 13 files changed, 302 insertions(+), 173 deletions(-)