OpenCloudOS-Kernel/arch/ia64
Frederic Weisbecker abf917cd91 cputime: Generic on-demand virtual cputime accounting
If we want to stop the tick further idle, we need to be
able to account the cputime without using the tick.

Virtual based cputime accounting solves that problem by
hooking into kernel/user boundaries.

However implementing CONFIG_VIRT_CPU_ACCOUNTING require
low level hooks and involves more overhead. But we already
have a generic context tracking subsystem that is required
for RCU needs by archs which plan to shut down the tick
outside idle.

This patch implements a generic virtual based cputime
accounting that relies on these generic kernel/user hooks.

There are some upsides of doing this:

- This requires no arch code to implement CONFIG_VIRT_CPU_ACCOUNTING
if context tracking is already built (already necessary for RCU in full
tickless mode).

- We can rely on the generic context tracking subsystem to dynamically
(de)activate the hooks, so that we can switch anytime between virtual
and tick based accounting. This way we don't have the overhead
of the virtual accounting when the tick is running periodically.

And one downside:

- There is probably more overhead than a native virtual based cputime
accounting. But this relies on hooks that are already set anyway.

Signed-off-by: Frederic 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>
2013-01-27 19:23:27 +01:00
..
configs [IA64] defconfig: Remove CONFIG_MISC_DEVICES 2012-08-20 13:04:29 -07:00
dig Disintegrate asm/system.h for IA64 2012-03-28 18:30:02 +01:00
hp TTY: call tty_port_destroy in the rest of drivers 2012-11-15 17:20:58 -08:00
include cputime: Generic on-demand virtual cputime accounting 2013-01-27 19:23:27 +01:00
kernel cputime: Generic on-demand virtual cputime accounting 2013-01-27 19:23:27 +01:00
kvm Merge tag 'kvm-3.8-1' of git://git.kernel.org/pub/scm/virt/kvm/kvm 2012-12-13 15:31:08 -08:00
lib Fix common misspellings 2011-03-31 11:26:23 -03:00
mm IA64: drivers: remove __dev* attributes. 2013-01-03 15:57:13 -08:00
oprofile Disintegrate asm/system.h for IA64 2012-03-28 18:30:02 +01:00
pci IA64: drivers: remove __dev* attributes. 2013-01-03 15:57:13 -08:00
scripts scripts: change scripts to use system python instead of env 2010-02-02 14:33:56 +01:00
sn IA64: drivers: remove __dev* attributes. 2013-01-03 15:57:13 -08:00
uv ia64: change to new flag variables 2011-03-17 14:02:56 +01:00
xen IA64: drivers: remove __dev* attributes. 2013-01-03 15:57:13 -08:00
Kconfig Bury the conditionals from kernel_thread/kernel_execve series 2012-12-19 18:07:38 -05:00
Kconfig.debug
Makefile Merge commit 'v2.6.35' into kbuild/kbuild 2010-08-04 13:59:13 +02:00
install.sh kbuild: use INSTALLKERNEL to select customized installkernel script 2009-09-20 12:18:14 +02:00
module.lds