This is a note to let you know that I've just added the patch titled sparc/ftrace: Fix ftrace graph time measurement to the 4.11-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: sparc-ftrace-fix-ftrace-graph-time-measurement.patch and it can be found in the queue-4.11 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From foo@baz Wed May 31 16:49:09 JST 2017 From: "Liam R. Howlett" <Liam.Howlett@xxxxxxxxxx> Date: Wed, 17 May 2017 11:47:00 -0400 Subject: sparc/ftrace: Fix ftrace graph time measurement From: "Liam R. Howlett" <Liam.Howlett@xxxxxxxxxx> [ Upstream commit 48078d2dac0a26f84f5f3ec704f24f7c832cce14 ] The ftrace function_graph time measurements of a given function is not accurate according to those recorded by ftrace using the function filters. This change pulls the x86_64 fix from 'commit 722b3c746953 ("ftrace/graph: Trace function entry before updating index")' into the sparc specific prepare_ftrace_return which stops ftrace from counting interrupted tasks in the time measurement. Example measurements for select_task_rq_fair running "hackbench 100 process 1000": | tracing/trace_stat/function0 | function_graph Before patch | 2.802 us | 4.255 us After patch | 2.749 us | 3.094 us Signed-off-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- arch/sparc/kernel/ftrace.c | 13 ++++++------- 1 file changed, 6 insertions(+), 7 deletions(-) --- a/arch/sparc/kernel/ftrace.c +++ b/arch/sparc/kernel/ftrace.c @@ -130,17 +130,16 @@ unsigned long prepare_ftrace_return(unsi if (unlikely(atomic_read(¤t->tracing_graph_pause))) return parent + 8UL; - if (ftrace_push_return_trace(parent, self_addr, &trace.depth, - frame_pointer, NULL) == -EBUSY) - return parent + 8UL; - trace.func = self_addr; + trace.depth = current->curr_ret_stack + 1; /* Only trace if the calling function expects to */ - if (!ftrace_graph_entry(&trace)) { - current->curr_ret_stack--; + if (!ftrace_graph_entry(&trace)) + return parent + 8UL; + + if (ftrace_push_return_trace(parent, self_addr, &trace.depth, + frame_pointer, NULL) == -EBUSY) return parent + 8UL; - } return return_hooker; } Patches currently in stable-queue which might be from Liam.Howlett@xxxxxxxxxx are queue-4.11/sparc-ftrace-fix-ftrace-graph-time-measurement.patch