Commit-ID: 78c89ba121221d9224a5747803d7fffe51cd6e44
Gitweb: http://git.kernel.org/tip/78c89ba121221d9224a5747803d7fffe51cd6e44
Author: Steven Rostedt <srostedt@xxxxxxxxxx>
AuthorDate: Tue, 5 Oct 2010 23:22:19 -0400
Committer: Steven Rostedt <rostedt@xxxxxxxxxxx>
CommitDate: Mon, 18 Oct 2010 10:53:38 -0400
tracing: Remove parent recording in latency tracer graph options
Even though the parent is recorded with the normal function tracing
of the latency tracers (irqsoff and wakeup), the function graph
recording is bogus.
This is due to the function graph messing with the return stack.
The latency tracers pass in as the parent CALLER_ADDR0, which
works fine for plain function tracing. But this causes bogus output
with the graph tracer:
3) <idle>-0 | d.s3. 0.000 us | return_to_handler();
3) <idle>-0 | d.s3. 0.000 us | _raw_spin_unlock_irqrestore();
3) <idle>-0 | d.s3. 0.000 us | return_to_handler();
3) <idle>-0 | d.s3. 0.000 us | trace_hardirqs_on();
The "return_to_handle()" call is the trampoline of the
function graph tracer, and is meaningless in this context.
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Signed-off-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
---
kernel/trace/trace_functions_graph.c | 1 -
1 files changed, 0 insertions(+), 1 deletions(-)
diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c
index 6f8fe28..76b0598 100644
--- a/kernel/trace/trace_functions_graph.c
+++ b/kernel/trace/trace_functions_graph.c
@@ -287,7 +287,6 @@ trace_graph_function(struct trace_array *tr,
unsigned long ip, unsigned long parent_ip,
unsigned long flags, int pc)
{
- __trace_graph_function(tr, parent_ip, flags, pc);
__trace_graph_function(tr, ip, flags, pc);
}
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