From 0793a61d4df8daeac6492dbf8d2f3e5713caae5e Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Thu, 4 Dec 2008 20:12:29 +0100 Subject: 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 Signed-off-by: Ingo Molnar --- init/Kconfig | 29 +++++++++++++++++++++++++++++ 1 file changed, 29 insertions(+) (limited to 'init') diff --git a/init/Kconfig b/init/Kconfig index f763762d544a..78bede218f10 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 -- cgit v1.2.3 From 4c59e4676dc95f6f58a2cff5390b2699fa5b5549 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Mon, 8 Dec 2008 19:38:33 +0100 Subject: perfcounters: select ANON_INODES The perfcounters subsystem depends on CONFIG_ANON_INODES facilities, so make sure it's selected. Signed-off-by: Ingo Molnar --- init/Kconfig | 1 + 1 file changed, 1 insertion(+) (limited to 'init') diff --git a/init/Kconfig b/init/Kconfig index 78bede218f10..7d147a36e968 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -741,6 +741,7 @@ config PERF_COUNTERS bool "Kernel Performance Counters" depends on HAVE_PERF_COUNTERS default y + select ANON_INODES help Enable kernel support for performance counter hardware. -- cgit v1.2.3 From e077df4f439681e43f0db8255b2d215b342ebdc6 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 19 Mar 2009 20:26:17 +0100 Subject: perf_counter: hook up the tracepoint events Impact: new perfcounters feature Enable usage of tracepoints as perf counter events. tracepoint event ids can be found in /debug/tracing/event/*/*/id and (for now) are represented as -65536+id in the type field. Signed-off-by: Peter Zijlstra Cc: Paul Mackerras Cc: Steven Rostedt Orig-LKML-Reference: <20090319194233.744044174@chello.nl> Signed-off-by: Ingo Molnar --- include/linux/perf_counter.h | 3 +++ init/Kconfig | 5 +++++ kernel/perf_counter.c | 43 +++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 51 insertions(+) (limited to 'init') diff --git a/include/linux/perf_counter.h b/include/linux/perf_counter.h index 08c11a6afebc..065984c1ff57 100644 --- a/include/linux/perf_counter.h +++ b/include/linux/perf_counter.h @@ -53,6 +53,8 @@ enum hw_event_types { PERF_COUNT_PAGE_FAULTS_MAJ = -7, PERF_SW_EVENTS_MIN = -8, + + PERF_TP_EVENTS_MIN = -65536 }; /* @@ -222,6 +224,7 @@ struct perf_counter { struct perf_data *usrdata; struct perf_data data[2]; + void (*destroy)(struct perf_counter *); struct rcu_head rcu_head; #endif }; diff --git a/init/Kconfig b/init/Kconfig index 38a2ecd47c37..4f647142f2e6 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -947,6 +947,11 @@ config PERF_COUNTERS Say Y if unsure. +config EVENT_PROFILE + bool "Tracepoint profile sources" + depends on PERF_COUNTERS && EVENT_TRACER + default y + endmenu config VM_EVENT_COUNTERS diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c index 97f891ffeb40..0bbe3e45ba0d 100644 --- a/kernel/perf_counter.c +++ b/kernel/perf_counter.c @@ -1152,6 +1152,9 @@ static void free_counter_rcu(struct rcu_head *head) static void free_counter(struct perf_counter *counter) { + if (counter->destroy) + counter->destroy(counter); + call_rcu(&counter->rcu_head, free_counter_rcu); } @@ -1727,6 +1730,45 @@ static const struct hw_perf_counter_ops perf_ops_cpu_migrations = { .read = cpu_migrations_perf_counter_read, }; +#ifdef CONFIG_EVENT_PROFILE +void perf_tpcounter_event(int event_id) +{ + perf_swcounter_event(PERF_TP_EVENTS_MIN + event_id, 1, 1, + task_pt_regs(current)); +} + +extern int ftrace_profile_enable(int); +extern void ftrace_profile_disable(int); + +static void tp_perf_counter_destroy(struct perf_counter *counter) +{ + int event_id = counter->hw_event.type - PERF_TP_EVENTS_MIN; + + ftrace_profile_disable(event_id); +} + +static const struct hw_perf_counter_ops * +tp_perf_counter_init(struct perf_counter *counter) +{ + int event_id = counter->hw_event.type - PERF_TP_EVENTS_MIN; + int ret; + + ret = ftrace_profile_enable(event_id); + if (ret) + return NULL; + + counter->destroy = tp_perf_counter_destroy; + + return &perf_ops_generic; +} +#else +static const struct hw_perf_counter_ops * +tp_perf_counter_init(struct perf_counter *counter) +{ + return NULL; +} +#endif + static const struct hw_perf_counter_ops * sw_perf_counter_init(struct perf_counter *counter) { @@ -1772,6 +1814,7 @@ sw_perf_counter_init(struct perf_counter *counter) hw_ops = &perf_ops_cpu_migrations; break; default: + hw_ops = tp_perf_counter_init(counter); break; } -- cgit v1.2.3 From 8dc8e5e8bc0ce00b0f656bf972f67cd8a72759e5 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Thu, 11 Jun 2009 16:13:24 +0200 Subject: perf_counter: Turn off by default Perfcounters were enabled by default to help testing - but now that we are submitting it upstream, make it default-disabled. Cc: Peter Zijlstra Cc: Mike Galbraith Cc: Paul Mackerras Cc: Arnaldo Carvalho de Melo LKML-Reference: Signed-off-by: Ingo Molnar --- init/Kconfig | 1 - 1 file changed, 1 deletion(-) (limited to 'init') diff --git a/init/Kconfig b/init/Kconfig index 8158f1f44694..aef16f9b3d23 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -941,7 +941,6 @@ menu "Performance Counters" config PERF_COUNTERS bool "Kernel Performance Counters" depends on HAVE_PERF_COUNTERS - default y select ANON_INODES help Enable kernel support for performance counter hardware. -- cgit v1.2.3