summaryrefslogtreecommitdiff
path: root/init/Kconfig
diff options
context:
space:
mode:
Diffstat (limited to 'init/Kconfig')
-rw-r--r--init/Kconfig55
1 files changed, 33 insertions, 22 deletions
diff --git a/init/Kconfig b/init/Kconfig
index 85c24ff9484d..c7bac39d6c61 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -331,7 +331,8 @@ config TREE_PREEMPT_RCU
This option selects the RCU implementation that is
designed for very large SMP systems with hundreds or
thousands of CPUs, but for which real-time response
- is also required.
+ is also required. It also scales down nicely to
+ smaller systems.
endchoice
@@ -915,31 +916,36 @@ config AIO
by some high performance threaded applications. Disabling
this option saves about 7k.
-config HAVE_PERF_COUNTERS
+config HAVE_PERF_EVENTS
bool
help
See tools/perf/design.txt for details.
-menu "Performance Counters"
+menu "Kernel Performance Events And Counters"
-config PERF_COUNTERS
- bool "Kernel Performance Counters"
- default y if PROFILING
- depends on HAVE_PERF_COUNTERS
+config PERF_EVENTS
+ bool "Kernel performance events and counters"
+ default y if (PROFILING || PERF_COUNTERS)
+ depends on HAVE_PERF_EVENTS
select ANON_INODES
help
- Enable kernel support for performance counter hardware.
+ Enable kernel support for various performance events provided
+ by software and hardware.
+
+ Software events are supported either build-in or via the
+ use of generic tracepoints.
- Performance counters are special hardware registers available
- on most modern CPUs. These registers count the number of certain
+ Most modern CPUs support performance events via performance
+ counter registers. 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
+ The Linux Performance Event subsystem provides an abstraction of
+ these software and hardware cevent apabilities, available via a
+ system call and used by the "perf" utility in tools/perf/. It
provides per task and per CPU counters, and it provides event
capabilities on top of those.
@@ -947,17 +953,29 @@ config PERF_COUNTERS
config EVENT_PROFILE
bool "Tracepoint profiling sources"
- depends on PERF_COUNTERS && EVENT_TRACING
+ depends on PERF_EVENTS && EVENT_TRACING
default y
help
- Allow the use of tracepoints as software performance counters.
+ Allow the use of tracepoints as software performance events.
- When this is enabled, you can create perf counters based on
+ When this is enabled, you can create perf events 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.)
+config PERF_COUNTERS
+ bool "Kernel performance counters (old config option)"
+ depends on HAVE_PERF_EVENTS
+ help
+ This config has been obsoleted by the PERF_EVENTS
+ config option - please see that one for details.
+
+ It has no effect on the kernel whether you enable
+ it or not, it is a compatibility placeholder.
+
+ Say N if unsure.
+
endmenu
config VM_EVENT_COUNTERS
@@ -1046,13 +1064,6 @@ config PROFILING
config TRACEPOINTS
bool
-config MARKERS
- bool "Activate markers"
- select TRACEPOINTS
- help
- Place an empty function call at each marker site. Can be
- dynamically changed for a probe function.
-
source "arch/Kconfig"
config SLOW_WORK