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| author | Ingo Molnar <mingo@elte.hu> | 2007-06-01 00:47:16 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-06-01 08:18:30 -0700 |
| commit | c1a834dc704763673df10282995257f2de93cbe9 (patch) | |
| tree | 66a0bc5ffbf6732eaa5fc6f554c13b235005c4cd /lib/Kconfig.debug | |
| parent | 9fcc15ec3c1c287a781a4620e52522b6186f26f6 (diff) | |
| download | lwn-c1a834dc704763673df10282995257f2de93cbe9.tar.gz lwn-c1a834dc704763673df10282995257f2de93cbe9.zip | |
timer stats: speedups
Make timer-stats have almost zero overhead when enabled in the config but
not used. (this way distros can enable it more easily)
Also update the documentation about overhead of timer_stats - it was
written for the first version which had a global lock and a linear list
walk based lookup ;-)
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'lib/Kconfig.debug')
| -rw-r--r-- | lib/Kconfig.debug | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 1ba77ca7d165..da95e10cfd70 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -126,7 +126,10 @@ config TIMER_STATS reprogrammed. The statistics can be read from /proc/timer_stats. The statistics collection is started by writing 1 to /proc/timer_stats, writing 0 stops it. This feature is useful to collect information - about timer usage patterns in kernel and userspace. + about timer usage patterns in kernel and userspace. This feature + is lightweight if enabled in the kernel config but not activated + (it defaults to deactivated on bootup and will only be activated + if some application like powertop activates it explicitly). config DEBUG_SLAB bool "Debug slab memory allocations" |