Re: [PATCH 0/3] fgraph: Do not save calltime in shadow stack

From: Google
Date: Sun Sep 15 2024 - 01:22:45 EST


On Sat, 14 Sep 2024 17:48:05 -0400
Steven Rostedt <rostedt@xxxxxxxxxxx> wrote:

>
> Now that there's more users of the function graph infrastructure, the
> calltime field on the shadow stack wastes space and also getting the
> timestamp is a waste of time for those that do not use it.
>
> Instead, have the only two users of it (function graph tracer and the
> profiler) store it in its own shadow stack variable.

This series looks good to me. Instead of adding add-hoc flag, this
solves call-time clearer.

For this series,

Acked-by: Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>

Thank you,

>
> Steven Rostedt (3):
> fgraph: Use fgraph data to store subtime for profiler
> ftrace: Use a running sleeptime instead of saving in shadow stack
> ftrace: Have calltime be saved in the fgraph storage
>
> ----
> include/linux/ftrace.h | 5 +--
> include/linux/sched.h | 1 +
> kernel/trace/fgraph.c | 85 +++++++++++++++++++++---------------
> kernel/trace/ftrace.c | 45 +++++++++++++------
> kernel/trace/trace.h | 1 +
> kernel/trace/trace_functions_graph.c | 52 +++++++++++++++++++++-
> 6 files changed, 137 insertions(+), 52 deletions(-)


--
Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>