From 394ee07623cf556c8daae2b3c00cf5fea47f0811 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Mon, 30 Mar 2009 19:07:14 +0200 Subject: [PATCH] perf_counter: provide generic callchain bits Provide the generic callchain support bits. If hw_event->callchain is set the arch specific perf_callchain() function is called upon to provide a perf_callchain_entry structure filled with the current callchain. If it does so, it is added to the overflow output event. Signed-off-by: Peter Zijlstra Acked-by: Paul Mackerras Orig-LKML-Reference: <20090330171024.254266860@chello.nl> Signed-off-by: Ingo Molnar --- include/linux/perf_counter.h | 13 ++++++++++++- kernel/perf_counter.c | 27 +++++++++++++++++++++++++++ 2 files changed, 39 insertions(+), 1 deletion(-) diff --git a/include/linux/perf_counter.h b/include/linux/perf_counter.h index edf5bfb7ff51..43083afffe0f 100644 --- a/include/linux/perf_counter.h +++ b/include/linux/perf_counter.h @@ -140,8 +140,9 @@ struct perf_counter_hw_event { include_tid : 1, /* include the tid */ mmap : 1, /* include mmap data */ munmap : 1, /* include munmap data */ + callchain : 1, /* add callchain data */ - __reserved_1 : 52; + __reserved_1 : 51; __u32 extra_config_len; __u32 __reserved_4; @@ -219,6 +220,7 @@ enum perf_event_type { PERF_EVENT_OVERFLOW = 1UL << 31, __PERF_EVENT_IP = 1UL << 30, __PERF_EVENT_TID = 1UL << 29, + __PERF_EVENT_CALLCHAIN = 1UL << 28, }; #ifdef __KERNEL__ @@ -504,6 +506,15 @@ extern void perf_counter_mmap(unsigned long addr, unsigned long len, extern void perf_counter_munmap(unsigned long addr, unsigned long len, unsigned long pgoff, struct file *file); +#define MAX_STACK_DEPTH 255 + +struct perf_callchain_entry { + u64 nr; + u64 ip[MAX_STACK_DEPTH]; +}; + +extern struct perf_callchain_entry *perf_callchain(struct pt_regs *regs); + #else static inline void perf_counter_task_sched_in(struct task_struct *task, int cpu) { } diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c index d93e9ddf7848..860cdc26bd7a 100644 --- a/kernel/perf_counter.c +++ b/kernel/perf_counter.c @@ -1653,6 +1653,17 @@ void perf_counter_do_pending(void) __perf_pending_run(); } +/* + * Callchain support -- arch specific + */ + +struct perf_callchain_entry * +__attribute__((weak)) +perf_callchain(struct pt_regs *regs) +{ + return NULL; +} + /* * Output */ @@ -1764,6 +1775,8 @@ static void perf_output_simple(struct perf_counter *counter, struct { u32 pid, tid; } tid_entry; + struct perf_callchain_entry *callchain = NULL; + int callchain_size = 0; header.type = PERF_EVENT_OVERFLOW; header.size = sizeof(header); @@ -1781,6 +1794,17 @@ static void perf_output_simple(struct perf_counter *counter, header.size += sizeof(tid_entry); } + if (counter->hw_event.callchain) { + callchain = perf_callchain(regs); + + if (callchain) { + callchain_size = (1 + callchain->nr) * sizeof(u64); + + header.type |= __PERF_EVENT_CALLCHAIN; + header.size += callchain_size; + } + } + ret = perf_output_begin(&handle, counter, header.size, nmi); if (ret) return; @@ -1791,6 +1815,9 @@ static void perf_output_simple(struct perf_counter *counter, if (counter->hw_event.include_tid) perf_output_put(&handle, tid_entry); + if (callchain) + perf_output_copy(&handle, callchain, callchain_size); + perf_output_end(&handle); } -- GitLab