linux/arch/powerpc/platforms
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
..
8xx Disintegrate asm/system.h for PowerPC 2012-03-28 18:30:02 +01:00
40x powerpc: Add missing NULL terminator to avoid boot panic on PPC40x 2013-01-03 16:45:52 +11:00
44x POWERPC: drivers: remove __dev* attributes. 2013-01-03 15:57:04 -08:00
52xx POWERPC: drivers: remove __dev* attributes. 2013-01-03 15:57:04 -08:00
82xx POWERPC: drivers: remove __dev* attributes. 2013-01-03 15:57:04 -08:00
83xx POWERPC: drivers: remove __dev* attributes. 2013-01-03 15:57:04 -08:00
85xx POWERPC: drivers: remove __dev* attributes. 2013-01-03 15:57:04 -08:00
86xx POWERPC: drivers: remove __dev* attributes. 2013-01-03 15:57:04 -08:00
512x powerpc/512x: don't compile any platform DIU code if the DIU is not enabled 2012-12-03 22:13:34 +01:00
amigaone pcspkr: Cleanup Kconfig dependencies 2011-06-09 15:01:41 +02:00
cell POWERPC: drivers: remove __dev* attributes. 2013-01-03 15:57:04 -08:00
chrp POWERPC: drivers: remove __dev* attributes. 2013-01-03 15:57:04 -08:00
embedded6xx Disintegrate asm/system.h for PowerPC 2012-03-28 18:30:02 +01:00
maple POWERPC: drivers: remove __dev* attributes. 2013-01-03 15:57:04 -08:00
pasemi POWERPC: drivers: remove __dev* attributes. 2013-01-03 15:57:04 -08:00
powermac POWERPC: drivers: remove __dev* attributes. 2013-01-03 15:57:04 -08:00
powernv POWERPC: drivers: remove __dev* attributes. 2013-01-03 15:57:04 -08:00
prep powerpc: drop unused Kconfig symbols 2011-10-31 23:39:52 +01:00
ps3 POWERPC: drivers: remove __dev* attributes. 2013-01-03 15:57:04 -08:00
pseries cputime: Generic on-demand virtual cputime accounting 2013-01-27 19:23:27 +01:00
wsp POWERPC: drivers: remove __dev* attributes. 2013-01-03 15:57:04 -08:00
fsl_uli1575.c POWERPC: drivers: remove __dev* attributes. 2013-01-03 15:57:04 -08:00
Kconfig PPC: select EPAPR_PARAVIRT for all users of epapr hcalls 2012-10-05 23:38:37 +02:00
Kconfig.cputype cputime: Generalize CONFIG_VIRT_CPU_ACCOUNTING 2012-08-17 16:31:08 +02:00
Makefile powerpc: Remove the main legacy iSerie platform code 2012-03-09 10:35:11 +11:00