thread_stack__event() is used to create call stacks, by keeping track of calls and returns. Improve the handling of trace begin / end to allow for a trace that ends in a call.
Signed-off-by: Adrian Hunter <[email protected]> --- tools/perf/util/thread-stack.c | 35 +++++++++++++++++++++++++++++----- 1 file changed, 30 insertions(+), 5 deletions(-) diff --git a/tools/perf/util/thread-stack.c b/tools/perf/util/thread-stack.c index dd17d6a38d3a..cea28b9074c1 100644 --- a/tools/perf/util/thread-stack.c +++ b/tools/perf/util/thread-stack.c @@ -36,6 +36,7 @@ * @branch_count: the branch count when the entry was created * @cp: call path * @no_call: a 'call' was not seen + * @trace_end: a 'call' but trace ended */ struct thread_stack_entry { u64 ret_addr; @@ -44,6 +45,7 @@ struct thread_stack_entry { u64 branch_count; struct call_path *cp; bool no_call; + bool trace_end; }; /** @@ -112,7 +114,8 @@ static struct thread_stack *thread_stack__new(struct thread *thread, return ts; } -static int thread_stack__push(struct thread_stack *ts, u64 ret_addr) +static int thread_stack__push(struct thread_stack *ts, u64 ret_addr, + bool trace_end) { int err = 0; @@ -124,6 +127,7 @@ static int thread_stack__push(struct thread_stack *ts, u64 ret_addr) } } + ts->stack[ts->cnt].trace_end = trace_end; ts->stack[ts->cnt++].ret_addr = ret_addr; return err; @@ -150,6 +154,18 @@ static void thread_stack__pop(struct thread_stack *ts, u64 ret_addr) } } +static void thread_stack__pop_trace_end(struct thread_stack *ts) +{ + size_t i; + + for (i = ts->cnt; i; ) { + if (ts->stack[--i].trace_end) + ts->cnt = i; + else + return; + } +} + static bool thread_stack__in_kernel(struct thread_stack *ts) { if (!ts->cnt) @@ -254,10 +270,19 @@ int thread_stack__event(struct thread *thread, u32 flags, u64 from_ip, ret_addr = from_ip + insn_len; if (ret_addr == to_ip) return 0; /* Zero-length calls are excluded */ - return thread_stack__push(thread->ts, ret_addr); - } else if (flags & PERF_IP_FLAG_RETURN) { - if (!from_ip) - return 0; + return thread_stack__push(thread->ts, ret_addr, + flags && PERF_IP_FLAG_TRACE_END); + } else if (flags & PERF_IP_FLAG_TRACE_BEGIN) { + /* + * If the caller did not change the trace number (which would + * have flushed the stack) then try to make sense of the stack. + * Possibly, tracing began after returning to the current + * address, so try to pop that. Also, do not expect a call made + * when the trace ended, to return, so pop that. + */ + thread_stack__pop(thread->ts, to_ip); + thread_stack__pop_trace_end(thread->ts); + } else if ((flags & PERF_IP_FLAG_RETURN) && from_ip) { thread_stack__pop(thread->ts, to_ip); } -- 2.17.1
