From: Andrew Morton <akpm@linux-foundation.org>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: linux-kernel@vger.kernel.org, "Ingo Molnar" <mingo@kernel.org>,
"Frederic Weisbecker" <fweisbec@gmail.com>,
"Thomas Gleixner" <tglx@linutronix.de>,
"Abderrahmane Benbachir" <abderrahmane.benbachir@polymtl.ca>,
"Américo Wang" <xiyou.wangcong@gmail.com>,
"Peter Zijlstra" <peterz@infradead.org>
Subject: Re: [PATCH 0/3] [RFC] init, tracing: Add initcall trace events
Date: Fri, 23 Mar 2018 12:50:16 -0700 [thread overview]
Message-ID: <20180323125016.270ea1558fe2499b1a12bfd7@linux-foundation.org> (raw)
In-Reply-To: <20180323150241.878778199@goodmis.org>
On Fri, 23 Mar 2018 11:02:41 -0400 Steven Rostedt <rostedt@goodmis.org> wrote:
> A while ago we had a boot tracer. But it was eventually removed:
> commit 30dbb20e68e6f ("tracing: Remove boot tracer").
>
> The rational was because there is already a initcall_debug boot option
> that causes printk()s of all the initcall functions.
"rationale" :)
> The problem with the initcall_debug option is that printk() is awfully slow,
> and makes it difficult to see the real impact of initcalls. Mainly because
> a single printk() is usually slower than most initcall functions.
Not understanding this. We do it correctly:
calltime = ktime_get();
ret = fn();
rettime = ktime_get();
so the displayed initcall timing is independent of the printk()
execution time?
next prev parent reply other threads:[~2018-03-23 19:50 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-23 15:02 [PATCH 0/3] [RFC] init, tracing: Add initcall trace events Steven Rostedt
2018-03-23 15:02 ` [PATCH 1/3] init: Fix initcall0 name as it is "pure" not "early" Steven Rostedt
2018-03-23 15:02 ` [PATCH 2/3] init, tracing: Add initcall trace events Steven Rostedt
2018-03-23 15:02 ` [PATCH 3/3] init, tracing: instrument security and console " Steven Rostedt
2018-03-23 19:50 ` Andrew Morton [this message]
2018-03-23 20:04 ` [PATCH 0/3] [RFC] init, tracing: Add " Steven Rostedt
2018-03-26 8:42 ` Peter Zijlstra
2018-03-26 14:34 ` Steven Rostedt
2018-03-26 17:47 ` [PATCH 4/3] init, tracing: Have printk come through the trace events for initcall_debug Steven Rostedt
2018-03-27 1:50 ` [PATCH 0/3] [RFC] init, tracing: Add initcall trace events Joel Fernandes (Google)
2018-03-27 3:02 ` Steven Rostedt
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