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From: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: kosaki.motohiro@jp.fujitsu.com, linux-kernel@vger.kernel.org,
	Ingo Molnar <mingo@elte.hu>,
	Andrew Morton <akpm@linux-foundation.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Frederic Weisbecker <fweisbec@gmail.com>,
	Lai Jiangshan <laijs@cn.fujitsu.com>,
	Steven Rostedt <srostedt@redhat.com>
Subject: Re: [PATCH 05/16] tracing: show that buffer size is not expanded
Date: Fri, 13 Mar 2009 12:05:53 +0900 (JST)	[thread overview]
Message-ID: <20090313114953.43E2.A69D9226@jp.fujitsu.com> (raw)
In-Reply-To: <20090313023825.869949732@goodmis.org>

> From: Steven Rostedt <srostedt@redhat.com>
> 
> Impact: do not confuse user on small trace buffer sizes
> 
> When the system boots up, the trace buffer is small to conserve memory.
> It is only two pages per online CPU. When the tracer is used, it expands
> to the default value.
> 
> This can confuse the user if they look at the buffer size and see only
> 7, but then later they see 1408.
> 
>  # cat /debug/tracing/buffer_size_kb
> 7
> 
>  # echo sched_switch > /debug/tracing/current_tracer
> 
>  # cat /debug/tracing/buffer_size_kb
> 1408
> 
> This patch tries to help remove this confustion by showing that the
> buffer has not been expanded.
> 
>  # cat /debug/tracing/buffer_size_kb
> 7 (expanded: 1408)

Hi,

I have one question.
Why souldn't use following output?

sprintf(buf, "%lu\n", trace_buf_size >> 10);


My point is:
  - pure number output can hadle easily.
  - nobody need to know internal memory saving logic.




  reply	other threads:[~2009-03-13  3:06 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-03-13  2:37 [PATCH 00/16] [GIT PULL] updates for tip/tracing/ftrace Steven Rostedt
2009-03-13  2:37 ` [PATCH 01/16] tracing: fix comments about trace buffer resizing Steven Rostedt
2009-03-13  2:37 ` [PATCH 02/16] tracing: protect ring_buffer_expanded with trace_types_lock Steven Rostedt
2009-03-13  2:37 ` [PATCH 03/16] ring-buffer: use CONFIG_HOTPLUG_CPU not CONFIG_HOTPLUG Steven Rostedt
2009-03-13  2:37 ` [PATCH 04/16] ring-buffer: remove unneeded get_online_cpus Steven Rostedt
2009-03-13  2:37 ` [PATCH 05/16] tracing: show that buffer size is not expanded Steven Rostedt
2009-03-13  3:05   ` KOSAKI Motohiro [this message]
2009-03-13  3:20     ` Steven Rostedt
2009-03-13  3:28       ` KOSAKI Motohiro
2009-03-13  2:37 ` [PATCH 06/16] tracing/core: bring back raw trace_printk for dynamic formats strings Steven Rostedt
2009-03-13  2:37 ` [PATCH 07/16] tracing: make bprint event use the proper event id Steven Rostedt
2009-03-13  2:37 ` [PATCH 08/16] tracing: have event_trace_printk use static tracer Steven Rostedt
2009-03-13  2:49   ` Andrew Morton
2009-03-13  3:08     ` Steven Rostedt
2009-03-13  3:09   ` KOSAKI Motohiro
2009-03-13  3:17     ` Steven Rostedt
2009-03-13  3:28       ` KOSAKI Motohiro
2009-03-13  3:34         ` Steven Rostedt
2009-03-13  5:36         ` [tip:tracing/ftrace] tracing: add comment for use of double __builtin_consant_p Steven Rostedt
2009-03-13  2:37 ` [PATCH 09/16] tracing: export trace formats to user space Steven Rostedt
2009-03-13 15:03   ` Frederic Weisbecker
2009-03-13  2:37 ` [PATCH 10/16] tracing: fix stack tracer header Steven Rostedt
2009-03-13  2:37 ` [PATCH 11/16] tracing: explain why stack tracer is empty Steven Rostedt
2009-03-13  2:37 ` [PATCH 12/16] tracing: tracepoints for softirq entry/exit - add softirq-to-name array Steven Rostedt
2009-03-13  4:12   ` Andrew Morton
2009-03-13  4:22     ` Steven Rostedt
2009-03-13  2:37 ` [PATCH 13/16] tracing: tracepoints for softirq entry/exit - tracepoints Steven Rostedt
2009-03-13  2:37 ` [PATCH 14/16] tracing: Dont use tracing_record_cmdline() in workqueue tracer fix Steven Rostedt
2009-03-13  2:37 ` [PATCH 15/16] tracing: show event name in trace for TRACE_EVENT created events Steven Rostedt
2009-03-13  2:37 ` [PATCH 16/16] ring-buffer: document reader page design Steven Rostedt
2009-03-13  3:35 ` [PATCH 00/16] [GIT PULL] updates for tip/tracing/ftrace Ingo Molnar

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