From: Steven Rostedt <rostedt@goodmis.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: linux-kernel@vger.kernel.org, Ingo Molnar <mingo@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Juri Lelli <juri.lelli@gmail.com>,
Clark Williams <williams@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH 4/4] tracing: Add __print_ns_to_secs() and __print_ns_without_secs() helpers
Date: Tue, 23 Feb 2016 09:30:08 -0500 [thread overview]
Message-ID: <20160223093008.072e1955@gandalf.local.home> (raw)
In-Reply-To: <20160223140143.GK6356@twins.programming.kicks-ass.net>
On Tue, 23 Feb 2016 15:01:43 +0100
Peter Zijlstra <peterz@infradead.org> wrote:
> > We have "%llu.%09ul" which is two arguments in the printf(). And the
> > values we are processing can't be modified. Which is why the macro uses
> > ({ }) and creates a temp variable.
>
> Hurm,. yes that's not something easily done. We need a temporary limited
> in scope to the printf statement, and C doesn't really do that.
The nice thing is, the division is done on output, which is considered
the slow path. Having two divisions instead of just one may be
inconvenient, but it's not slowing much down. And that's only performed
when reading the ASCII trace files. If you use perf or trace-cmd, the
event-parser will do the work for you at post processing.
-- Steve
prev parent reply other threads:[~2016-02-23 14:30 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-02-22 21:26 [PATCH 0/4] sched: Display deadline bandwidth and other SCHED_DEBUG clean up Steven Rostedt
2016-02-22 21:26 ` [PATCH 1/4] sched: Move sched_feature file setup into debug.c Steven Rostedt
2016-02-29 11:16 ` [tip:sched/core] sched/debug: Move the /sys/kernel/debug/sched_features " tip-bot for Steven Rostedt (Red Hat)
2016-02-22 21:26 ` [PATCH 2/4] sched: Move sched_domain_sysctl to debug.c Steven Rostedt
2016-02-29 11:16 ` [tip:sched/core] sched/debug: " tip-bot for Steven Rostedt (Red Hat)
2016-02-22 21:26 ` [PATCH 3/4] sched: Add bandwidth ratio to /proc/sched_debug Steven Rostedt
2016-02-23 9:55 ` Juri Lelli
2016-02-29 11:16 ` [tip:sched/core] sched/debug: Add deadline scheduler " tip-bot for Steven Rostedt (Red Hat)
2016-02-22 21:26 ` [PATCH 4/4] tracing: Add __print_ns_to_secs() and __print_ns_without_secs() helpers Steven Rostedt
2016-02-23 12:49 ` Peter Zijlstra
2016-02-23 13:17 ` Steven Rostedt
2016-02-23 14:01 ` Peter Zijlstra
2016-02-23 14:30 ` Steven Rostedt [this message]
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