Messages in this thread | | | Date | Wed, 3 Dec 2008 09:13:01 +0100 | From | Ingo Molnar <> | Subject | Re: [PATCH 4/5] ftrace: function graph return for function entry |
| |
* Steven Rostedt <rostedt@goodmis.org> wrote:
> From: Steven Rostedt <srostedt@redhat.com> > > Impact: feature, let entry function decide to trace or not > > This patch lets the graph tracer entry function decide if the tracing > should be done at the end as well. This requires all function graph > entry functions return 1 if it should trace, or 0 if the return should > not be traced.
> diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S > index 47aa5f0..cef05a2 100644 > --- a/arch/x86/kernel/entry_64.S > +++ b/arch/x86/kernel/entry_64.S > @@ -119,6 +119,9 @@ ENTRY(mcount) > #ifdef CONFIG_FUNCTION_GRAPH_TRACER > cmpq $ftrace_stub, ftrace_graph_return > jnz ftrace_graph_caller > + > + cmpq $ftrace_graph_entry_stub, ftrace_graph_entry > + jnz ftrace_graph_caller
hm, that's in the hotpath. What's the point of this? Do we want some sort of configuration vector that allows per function graphing versus entry-only traces?
Ingo
| |