From: Johannes Berg <johannes@sipsolutions.net>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Christoph Hellwig <hch@infradead.org>,
LKML <linux-kernel@vger.kernel.org>,
Frederic Weisbecker <fweisbec@gmail.com>,
Ingo Molnar <mingo@redhat.com>
Subject: Re: [PATCH] tracing: add trace console
Date: Wed, 16 Nov 2011 21:12:59 +0100 [thread overview]
Message-ID: <1321474379.4502.17.camel@jlt3.sipsolutions.net> (raw)
In-Reply-To: <1321473443.4181.38.camel@frodo>
On Wed, 2011-11-16 at 14:57 -0500, Steven Rostedt wrote:
> On Wed, 2011-11-16 at 19:33 +0100, Johannes Berg wrote:
> > On Wed, 2011-11-16 at 12:00 -0500, Steven Rostedt wrote:
> > > On Wed, 2011-11-16 at 17:45 +0100, Johannes Berg wrote:
> > >
> > > > I briefly looked at it just after writing the email, but quickly got
> > > > lost in printk.c because of the multi-line handling it has. We could
> > > > instead trace each call to printk(), so the multi-line stuff would end
> > > > up in multiple events, but all of that code is too much vodoo for me :)
> > >
> > > Here's what can go into printk.c:
> > >
> > > diff --git a/kernel/printk.c b/kernel/printk.c
> > > index 1455a0d..4b8445a 100644
> > > --- a/kernel/printk.c
> > > +++ b/kernel/printk.c
> > > @@ -542,6 +542,7 @@ MODULE_PARM_DESC(ignore_loglevel, "ignore loglevel setting, to"
> > > static void _call_console_drivers(unsigned start,
> > > unsigned end, int msg_log_level)
> > > {
> > > + trace_console(&LOG_BUF(start), end - start);
> > > if ((msg_log_level < console_loglevel || ignore_loglevel) &&
> > > console_drivers && start != end) {
> > > if ((start & LOG_BUF_MASK) > (end & LOG_BUF_MASK)) {
> > >
> > >
> > > And then you can make a TRACE_EVENT(console) that takes a buffer and a
> > > len, and write that to the ring buffer.
> >
> > Yes, of course, but if we're going to modify the code then I thought we
> > should probably trace everything independent of the console printk
> > level.
> >
>
> This will trace everything independent from the console level. Noticed
> that I put the tracepoint before the msg_log_level is checked.
D'oh, right. Yeah that seems good. Too bad I discarded my previous
attempt already :)
johannes
next prev parent reply other threads:[~2011-11-16 20:13 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-11-16 10:18 [PATCH] tracing: add trace console Johannes Berg
2011-11-16 14:15 ` Steven Rostedt
2011-11-16 14:25 ` Peter Zijlstra
2011-11-16 14:30 ` Johannes Berg
2011-11-16 14:41 ` Peter Zijlstra
2011-11-16 14:48 ` Steven Rostedt
2011-11-16 14:50 ` Peter Zijlstra
2011-11-16 14:51 ` Johannes Berg
2011-11-16 15:17 ` Steven Rostedt
2011-11-16 14:32 ` Thomas Gleixner
2011-11-16 14:35 ` Frederic Weisbecker
2011-11-16 15:09 ` [PATCH v2] " Johannes Berg
2011-11-16 15:17 ` Peter Zijlstra
2011-11-16 15:19 ` Steven Rostedt
2011-11-16 15:10 ` [PATCH] " Christoph Hellwig
2011-11-16 15:17 ` Johannes Berg
2011-11-16 16:41 ` Steven Rostedt
2011-11-16 16:45 ` Johannes Berg
2011-11-16 17:00 ` Steven Rostedt
2011-11-16 17:05 ` Steven Rostedt
2011-11-16 18:33 ` Johannes Berg
2011-11-16 19:57 ` Steven Rostedt
2011-11-16 20:12 ` Johannes Berg [this message]
2011-11-16 21:25 ` [PATCH] printk: add console output tracing Johannes Berg
2011-11-17 1:01 ` Steven Rostedt
2011-11-17 14:55 ` Frederic Weisbecker
2011-11-17 14:57 ` Johannes Berg
2011-11-17 15:00 ` Frederic Weisbecker
2011-11-17 15:17 ` Steven Rostedt
2011-11-17 15:21 ` [PATCH v2] " Johannes Berg
2011-11-18 18:44 ` Frederic Weisbecker
2011-11-18 18:46 ` Johannes Berg
2011-11-18 18:54 ` Frederic Weisbecker
2011-11-18 18:59 ` Johannes Berg
2011-11-23 13:16 ` Frederic Weisbecker
2011-11-24 13:21 ` Johannes Berg
2011-11-24 15:45 ` Frederic Weisbecker
2011-11-24 19:00 ` Johannes Berg
2011-11-25 17:43 ` Frederic Weisbecker
2011-11-25 18:11 ` Johannes Berg
2011-11-24 19:03 ` [PATCH v3] " Johannes Berg
2011-11-25 17:41 ` Frederic Weisbecker
2011-12-02 18:05 ` Steven Rostedt
2012-02-13 17:30 ` Steven Rostedt
2012-02-13 17:33 ` Johannes Berg
2012-02-13 17:42 ` Steven Rostedt
2012-02-17 13:52 ` [tip:perf/core] printk/tracing: Add " tip-bot for Johannes Berg
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