From 4fef41bfb1d8d2ada4a18eb3ab80c2682bcbae12 Mon Sep 17 00:00:00 2001 From: Adrian Hunter Date: Wed, 1 Apr 2020 13:16:06 +0300 Subject: [PATCH] perf thread-stack: Add thread_stack__sample_late() Add a thread stack function to create a call chain for hardware events where the sample records get created some time after the event occurred. Signed-off-by: Adrian Hunter Cc: Andi Kleen Cc: Jiri Olsa Link: http://lore.kernel.org/lkml/20200401101613.6201-10-adrian.hunter@intel.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/thread-stack.c | 57 ++++++++++++++++++++++++++++++++++ tools/perf/util/thread-stack.h | 3 ++ 2 files changed, 60 insertions(+) diff --git a/tools/perf/util/thread-stack.c b/tools/perf/util/thread-stack.c index 0885967d5bc3..83f6c83f5617 100644 --- a/tools/perf/util/thread-stack.c +++ b/tools/perf/util/thread-stack.c @@ -497,6 +497,63 @@ void thread_stack__sample(struct thread *thread, int cpu, chain->nr = i; } +/* + * Hardware sample records, created some time after the event occurred, need to + * have subsequent addresses removed from the call chain. + */ +void thread_stack__sample_late(struct thread *thread, int cpu, + struct ip_callchain *chain, size_t sz, + u64 sample_ip, u64 kernel_start) +{ + struct thread_stack *ts = thread__stack(thread, cpu); + u64 sample_context = callchain_context(sample_ip, kernel_start); + u64 last_context, context, ip; + size_t nr = 0, j; + + if (sz < 2) { + chain->nr = 0; + return; + } + + if (!ts) + goto out; + + /* + * When tracing kernel space, kernel addresses occur at the top of the + * call chain after the event occurred but before tracing stopped. + * Skip them. + */ + for (j = 1; j <= ts->cnt; j++) { + ip = ts->stack[ts->cnt - j].ret_addr; + context = callchain_context(ip, kernel_start); + if (context == PERF_CONTEXT_USER || + (context == sample_context && ip == sample_ip)) + break; + } + + last_context = sample_ip; /* Use sample_ip as an invalid context */ + + for (; nr < sz && j <= ts->cnt; nr++, j++) { + ip = ts->stack[ts->cnt - j].ret_addr; + context = callchain_context(ip, kernel_start); + if (context != last_context) { + if (nr >= sz - 1) + break; + chain->ips[nr++] = context; + last_context = context; + } + chain->ips[nr] = ip; + } +out: + if (nr) { + chain->nr = nr; + } else { + chain->ips[0] = sample_context; + chain->ips[1] = sample_ip; + chain->nr = 2; + } +} + struct call_return_processor * call_return_processor__new(int (*process)(struct call_return *cr, u64 *parent_db_id, void *data), void *data) diff --git a/tools/perf/util/thread-stack.h b/tools/perf/util/thread-stack.h index e1ec5a58f1b2..8962ddc4e1ab 100644 --- a/tools/perf/util/thread-stack.h +++ b/tools/perf/util/thread-stack.h @@ -85,6 +85,9 @@ int thread_stack__event(struct thread *thread, int cpu, u32 flags, u64 from_ip, void thread_stack__set_trace_nr(struct thread *thread, int cpu, u64 trace_nr); void thread_stack__sample(struct thread *thread, int cpu, struct ip_callchain *chain, size_t sz, u64 ip, u64 kernel_start); +void thread_stack__sample_late(struct thread *thread, int cpu, + struct ip_callchain *chain, size_t sz, u64 ip, + u64 kernel_start); int thread_stack__flush(struct thread *thread); void thread_stack__free(struct thread *thread); size_t thread_stack__depth(struct thread *thread, int cpu); -- 2.20.1