tracing, perf_counter: Add help text to CONFIG_EVENT_PROFILE

[safe/jmp/linux-2.6] / init / Kconfig

diff --git a/init/Kconfig b/init/Kconfig
index d4e9671..823ee0a 100644 (file)
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -16,6 +16,11 @@ config DEFCONFIG_LIST
        default "$ARCH_DEFCONFIG"
        default "arch/$ARCH/defconfig"
 
+config CONSTRUCTORS
+       bool
+       depends on !UML
+       default y
+
 menu "General setup"
 
 config EXPERIMENTAL
@@ -302,7 +307,8 @@ config AUDITSYSCALL
 
 config AUDIT_TREE
        def_bool y
-       depends on AUDITSYSCALL && INOTIFY
+       depends on AUDITSYSCALL
+       select INOTIFY
 
 menu "RCU Subsystem"
 
@@ -615,13 +621,13 @@ config SYSFS_DEPRECATED
        bool
 
 config SYSFS_DEPRECATED_V2
-       bool "Create deprecated sysfs layout for older userspace tools"
+       bool "remove sysfs features which may confuse old userspace tools"
        depends on SYSFS
-       default y
+       default n
        select SYSFS_DEPRECATED
        help
          This option switches the layout of sysfs to the deprecated
-         version.
+         version. Do not use it on recent distributions.
 
          The current sysfs layout features a unified device tree at
          /sys/devices/, which is able to express a hierarchy between
@@ -808,14 +814,6 @@ config KALLSYMS_EXTRA_PASS
           you wait for kallsyms to be fixed.
 
 
-config STRIP_ASM_SYMS
-       bool "Strip assembler-generated symbols during link"
-       default n
-       help
-         Strip internal assembler-generated symbols during a link (symbols
-         that look like '.Lxxx') so they don't pollute the output of
-         get_wchan() and suchlike.
-
 config HOTPLUG
        bool "Support for hot-pluggable devices" if EMBEDDED
        default y
@@ -933,6 +931,50 @@ config AIO
           by some high performance threaded applications. Disabling
           this option saves about 7k.
 
+config HAVE_PERF_COUNTERS
+       bool
+       help
+         See tools/perf/design.txt for details.
+
+menu "Performance Counters"
+
+config PERF_COUNTERS
+       bool "Kernel Performance Counters"
+       depends on HAVE_PERF_COUNTERS
+       select ANON_INODES
+       help
+         Enable kernel support for performance counter hardware.
+
+         Performance counters are special hardware registers available
+         on most modern CPUs. These registers count the number of certain
+         types of hw events: such as instructions executed, cachemisses
+         suffered, or branches mis-predicted - without slowing down the
+         kernel or applications. These registers can also trigger interrupts
+         when a threshold number of events have passed - and can thus be
+         used to profile the code that runs on that CPU.
+
+         The Linux Performance Counter subsystem provides an abstraction of
+         these hardware capabilities, available via a system call. It
+         provides per task and per CPU counters, and it provides event
+         capabilities on top of those.
+
+         Say Y if unsure.
+
+config EVENT_PROFILE
+       bool "Tracepoint profiling sources"
+       depends on PERF_COUNTERS && EVENT_TRACING
+       default y
+       help
+        Allow the use of tracepoints as software performance counters.
+
+        When this is enabled, you can create perf counters based on
+        tracepoints using PERF_TYPE_TRACEPOINT and the tracepoint ID
+        found in debugfs://tracing/events/*/*/id. (The -e/--events
+        option to the perf tool can parse and interpret symbolic
+        tracepoints, in the subsystem:tracepoint_name format.)
+
+endmenu
+
 config VM_EVENT_COUNTERS
        default y
        bool "Enable VM event counters for /proc/vmstat" if EMBEDDED
@@ -961,6 +1003,14 @@ config SLUB_DEBUG
          SLUB sysfs support. /sys/slab will not exist and there will be
          no support for cache validation etc.
 
+config STRIP_ASM_SYMS
+       bool "Strip assembler-generated symbols during link"
+       default n
+       help
+         Strip internal assembler-generated symbols during a link (symbols
+         that look like '.Lxxx') so they don't pollute the output of
+         get_wchan() and suchlike.
+
 config COMPAT_BRK
        bool "Disable heap randomization"
        default y