From: Masami Hiramatsu (Google) <mhiramat@kernel.org>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org,
Mark Rutland <mark.rutland@arm.com>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Andrew Morton <akpm@linux-foundation.org>,
Alexei Starovoitov <alexei.starovoitov@gmail.com>,
Florent Revest <revest@chromium.org>,
Martin KaFai Lau <martin.lau@linux.dev>,
bpf <bpf@vger.kernel.org>, Sven Schnelle <svens@linux.ibm.com>,
Alexei Starovoitov <ast@kernel.org>, Jiri Olsa <jolsa@kernel.org>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Alan Maguire <alan.maguire@oracle.com>,
Peter Zijlstra <peterz@infradead.org>,
Thomas Gleixner <tglx@linutronix.de>, Guo Ren <guoren@kernel.org>
Subject: Re: [PATCH v2 24/27] function_graph: Use static_call and branch to optimize entry function
Date: Tue, 4 Jun 2024 08:08:56 +0900 [thread overview]
Message-ID: <20240604080856.907194a1fc3106be0cc94fa0@kernel.org> (raw)
In-Reply-To: <20240603110752.6b722aac@gandalf.local.home>
On Mon, 3 Jun 2024 11:07:52 -0400
Steven Rostedt <rostedt@goodmis.org> wrote:
> On Mon, 3 Jun 2024 11:00:18 -0400
> Steven Rostedt <rostedt@goodmis.org> wrote:
>
> > Yes, but that gets a bit complex, and requires the changing of all archs.
> > If it starts to become a problem, I rather add that as a feature. That is,
> > we can always go back to it. But for now, lets keep the complexity down.
>
> And if we were to go the route of calling a single fgraph_ops caller, I
> would want it choreographed with ftrace, such that the direct caller calls
> a different fgraph function only if it has only one graph caller on it and
> the fgraph loop function if a function has more than one. Just like the
> ftrace code does.
>
> If we are going to go that route, let's do it right.
Yes, that is what I expect. ftrace_ops has a callback for loop and subops
has another direct callbacks, and the ftrace_ops has a flag to direct subops
assign. In this case ftrace will assign the subops's direct callback for
single subops entries.
But anyway, this optimization can be done afterwards. Especially this feature
is important for fprobes on fgraph, until that, the current implementation is
enough.
Thank you,
>
> -- Steve
--
Masami Hiramatsu (Google) <mhiramat@kernel.org>
next prev parent reply other threads:[~2024-06-03 23:09 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-06-02 3:37 [PATCH v2 00/27] function_graph: Allow multiple users for function graph tracing Steven Rostedt
2024-06-02 3:37 ` [PATCH v2 01/27] function_graph: Convert ret_stack to a series of longs Steven Rostedt
2024-06-02 3:37 ` [PATCH v2 02/27] fgraph: Use BUILD_BUG_ON() to make sure we have structures divisible by long Steven Rostedt
2024-06-02 3:37 ` [PATCH v2 03/27] function_graph: Add an array structure that will allow multiple callbacks Steven Rostedt
2024-06-02 3:37 ` [PATCH v2 04/27] function_graph: Allow multiple users to attach to function graph Steven Rostedt
2024-06-02 3:37 ` [PATCH v2 05/27] function_graph: Handle tail calls for stack unwinding Steven Rostedt
2024-06-02 3:37 ` [PATCH v2 06/27] function_graph: Remove logic around ftrace_graph_entry and return Steven Rostedt
2024-06-02 3:37 ` [PATCH v2 07/27] ftrace/function_graph: Pass fgraph_ops to function graph callbacks Steven Rostedt
2024-06-02 3:37 ` [PATCH v2 08/27] ftrace: Allow function_graph tracer to be enabled in instances Steven Rostedt
2024-06-02 3:37 ` [PATCH v2 09/27] ftrace: Allow ftrace startup flags to exist without dynamic ftrace Steven Rostedt
2024-06-02 3:37 ` [PATCH v2 10/27] ftrace: Add subops logic to allow one ops to manage many Steven Rostedt
2024-06-03 1:33 ` Masami Hiramatsu
2024-06-03 2:06 ` Steven Rostedt
2024-06-03 2:46 ` Masami Hiramatsu
2024-06-03 14:54 ` Steven Rostedt
2024-06-03 17:05 ` Steven Rostedt
2024-06-02 3:37 ` [PATCH v2 11/27] ftrace: Allow subops filtering to be modified Steven Rostedt
2024-06-03 2:37 ` Masami Hiramatsu
2024-06-03 14:52 ` Steven Rostedt
2024-06-03 23:12 ` Masami Hiramatsu
2024-06-02 3:37 ` [PATCH v2 12/27] function_graph: Have the instances use their own ftrace_ops for filtering Steven Rostedt
2024-06-02 3:37 ` [PATCH v2 13/27] function_graph: Add pid tracing back to function graph tracer Steven Rostedt
2024-06-02 3:37 ` [PATCH v2 14/27] function_graph: Use a simple LRU for fgraph_array index number Steven Rostedt
2024-06-02 3:37 ` [PATCH v2 15/27] function_graph: Add "task variables" per task for fgraph_ops Steven Rostedt
2024-06-02 3:38 ` [PATCH v2 16/27] function_graph: Move set_graph_function tests to shadow stack global var Steven Rostedt
2024-06-02 3:38 ` [PATCH v2 17/27] function_graph: Move graph depth stored data " Steven Rostedt
2024-06-02 3:38 ` [PATCH v2 18/27] function_graph: Move graph notrace bit " Steven Rostedt
2024-06-02 3:38 ` [PATCH v2 19/27] function_graph: Implement fgraph_reserve_data() and fgraph_retrieve_data() Steven Rostedt
2024-06-02 3:38 ` [PATCH v2 20/27] function_graph: Add selftest for passing local variables Steven Rostedt
2024-06-02 3:38 ` [PATCH v2 21/27] ftrace: Add multiple fgraph storage selftest Steven Rostedt
2024-06-02 3:38 ` [PATCH v2 22/27] function_graph: Use for_each_set_bit() in __ftrace_return_to_handler() Steven Rostedt
2024-06-02 3:38 ` [PATCH v2 23/27] function_graph: Use bitmask to loop on fgraph entry Steven Rostedt
2024-06-02 3:38 ` [PATCH v2 24/27] function_graph: Use static_call and branch to optimize entry function Steven Rostedt
2024-06-03 3:11 ` Masami Hiramatsu
2024-06-03 15:00 ` Steven Rostedt
2024-06-03 15:07 ` Steven Rostedt
2024-06-03 23:08 ` Masami Hiramatsu [this message]
2024-06-02 3:38 ` [PATCH v2 25/27] function_graph: Use static_call and branch to optimize return function Steven Rostedt
2024-06-02 3:38 ` [PATCH v2 26/27] selftests/ftrace: Add function_graph tracer to func-filter-pid test Steven Rostedt
2024-06-02 3:38 ` [PATCH v2 27/27] selftests/ftrace: Add fgraph-multi.tc test Steven Rostedt
2024-06-02 3:44 ` [PATCH v2 00/27] function_graph: Allow multiple users for function graph tracing Steven Rostedt
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