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authorThomas Gleixner <tglx@linutronix.de>2008-12-04 20:12:29 +0100
committerIngo Molnar <mingo@elte.hu>2008-12-08 15:47:03 +0100
commit0793a61d4df8daeac6492dbf8d2f3e5713caae5e (patch)
treecc9603eb8daffeb7ace521c42a6a44db164ac551 /init
parentb5aa97e83bcc31a96374d18f5452d53909a16c90 (diff)
downloadop-kernel-dev-0793a61d4df8daeac6492dbf8d2f3e5713caae5e.zip
op-kernel-dev-0793a61d4df8daeac6492dbf8d2f3e5713caae5e.tar.gz
performance counters: core code
Implement the core kernel bits of Performance Counters subsystem. The Linux Performance Counter subsystem provides an abstraction of performance counter hardware capabilities. It provides per task and per CPU counters, and it provides event capabilities on top of those. Performance counters are accessed via special file descriptors. There's one file descriptor per virtual counter used. The special file descriptor is opened via the perf_counter_open() system call: int perf_counter_open(u32 hw_event_type, u32 hw_event_period, u32 record_type, pid_t pid, int cpu); The syscall returns the new fd. The fd can be used via the normal VFS system calls: read() can be used to read the counter, fcntl() can be used to set the blocking mode, etc. Multiple counters can be kept open at a time, and the counters can be poll()ed. See more details in Documentation/perf-counters.txt. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'init')
-rw-r--r--init/Kconfig29
1 files changed, 29 insertions, 0 deletions
diff --git a/init/Kconfig b/init/Kconfig
index f763762..78bede2 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -732,6 +732,35 @@ config AIO
by some high performance threaded applications. Disabling
this option saves about 7k.
+config HAVE_PERF_COUNTERS
+ bool
+
+menu "Performance Counters"
+
+config PERF_COUNTERS
+ bool "Kernel Performance Counters"
+ depends on HAVE_PERF_COUNTERS
+ default y
+ 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.
+
+endmenu
+
config VM_EVENT_COUNTERS
default y
bool "Enable VM event counters for /proc/vmstat" if EMBEDDED
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