From: Steven Rostedt <rostedt@goodmis.org>
To: Junxuan Liao <ljx@cs.wisc.edu>
Cc: Frederic Weisbecker <frederic@kernel.org>,
"Paul E. McKenney" <paulmck@kernel.org>,
linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org,
Masami Hiramatsu <mhiramat@kernel.org>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Subject: Re: Interface for enabling context tracking
Date: Thu, 17 Apr 2025 16:34:36 -0400 [thread overview]
Message-ID: <20250417163436.599e50a1@gandalf.local.home> (raw)
In-Reply-To: <3ce02a98-0ac2-4d34-b6f7-ba85088399d7@cs.wisc.edu>
On Thu, 17 Apr 2025 14:10:53 -0500
Junxuan Liao <ljx@cs.wisc.edu> wrote:
> Just found out that the exit tracepoints for syscalls aren't always
> exactly preceding the exit to userspace. The kernel can still spend
> quite some time in task_work_run after the tracepoints are triggered.
> Has that bothered you before?
It's been a while, but what I usually do when I want to see entry into the
kernel is also to run:
trace-cmd set -p function_graph --max-graph-depth 1
Which tracks the first function call into the kernel. It obviously now
misses entry and exit from user mode due to noinstr, but if a task_work
function is called, it will usually catch that too.
-- Steve
next prev parent reply other threads:[~2025-04-17 20:32 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-04-10 18:51 Interface for enabling context tracking Junxuan Liao
2025-04-10 19:05 ` Steven Rostedt
2025-04-10 20:31 ` Junxuan Liao
2025-04-17 19:10 ` Junxuan Liao
2025-04-17 20:34 ` Steven Rostedt [this message]
2025-04-10 19:10 ` Paul E. McKenney
2025-04-10 19:32 ` Steven Rostedt
2025-04-11 17:41 ` Junxuan Liao
2025-04-11 21:51 ` Frederic Weisbecker
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