From: Steven Rostedt <rostedt@goodmis.org>
To: Andi Kleen <andi@firstfloor.org>
Cc: "Ted Ts'o" <tytso@mit.edu>, David Sharp <dhsharp@google.com>,
linux-kernel@vger.kernel.org, mrubin@google.com
Subject: Re: [Patch 00/15] Reduce tracing payload size.
Date: Mon, 06 Dec 2010 11:17:35 -0500 [thread overview]
Message-ID: <1291652255.16223.29.camel@gandalf.stny.rr.com> (raw)
In-Reply-To: <20101206145852.GA24977@basil.fritz.box>
On Mon, 2010-12-06 at 15:58 +0100, Andi Kleen wrote:
> On Mon, Dec 06, 2010 at 08:56:37AM -0500, Ted Ts'o wrote:
> > On Mon, Dec 06, 2010 at 02:22:00PM +0100, Andi Kleen wrote:
> > > David Sharp <dhsharp@google.com> writes:
> > > >
> > > > These patches are just a start to shrinking the size of trace events. I am
> > > > planning to also make small versions of trace events that are used when
> > > > CONFIG_SMALL_TRACES is enabled. I'm also open to discussion of other ways to
> > > > shrink event sizes.
> > >
> > > Maybe the simplest would be to lzo them as they get logged?
> > > I assume you already considered that?
> >
> > The tracing subsystem is supposed to be extremely low-overhead.
> > Compressiong the event log would add considerable CPU overhead. If we
>
> lzo as a rule of thumb is about as expensive as 3x memcpy()
> That's not really expensive.
Usually the most expensive thing in the trace is the memcpy(). Which is
why we try to do it only once.
-- Steve
next prev parent reply other threads:[~2010-12-06 16:17 UTC|newest]
Thread overview: 74+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-12-04 0:13 David Sharp
2010-12-04 0:13 ` [PATCH 01/15] tracing: Add a 'buffer_overwrite' debugfs file David Sharp
2010-12-04 1:57 ` Steven Rostedt
2010-12-08 20:15 ` David Sharp
2010-12-08 21:46 ` [PATCH] tracing: Add an 'overwrite' trace_option David Sharp
2010-12-14 0:39 ` David Sharp
2011-03-09 0:45 ` David Sharp
2011-03-11 9:45 ` [tip:perf/core] " tip-bot for David Sharp
2010-12-04 0:13 ` [PATCH 02/15] ring_buffer.c: Remove unused #include <linux/trace_irq.h> David Sharp
2011-03-11 9:46 ` [tip:perf/core] ring-buffer: " tip-bot for David Sharp
2010-12-04 0:13 ` [PATCH 03/15] ring_buffer: Align buffer_page struct allocations only to fit the flags David Sharp
2010-12-04 1:43 ` Steven Rostedt
2010-12-07 22:44 ` David Sharp
2010-12-04 0:13 ` [PATCH 04/15] ftrace: pack event structures David Sharp
2011-03-08 23:30 ` Steven Rostedt
2011-03-09 1:09 ` Steven Rostedt
2011-03-09 6:39 ` David Miller
2011-03-09 15:18 ` Steven Rostedt
2011-03-10 23:21 ` David Sharp
2011-03-11 3:37 ` Steven Rostedt
2011-03-09 13:01 ` Steven Rostedt
2010-12-04 0:13 ` [PATCH 05/15] ftrace: fix event alignment: ftrace:context_switch and ftrace:wakeup David Sharp
2011-03-11 9:48 ` [tip:perf/core] tracing: Fix " tip-bot for David Sharp
2010-12-04 0:13 ` [PATCH 06/15] ftrace: fix event alignment: module:module_request David Sharp
2010-12-04 1:47 ` Steven Rostedt
2010-12-06 1:28 ` Li Zefan
2011-03-11 9:48 ` [tip:perf/core] tracing: Fix " tip-bot for David Sharp
2010-12-04 0:13 ` [PATCH 07/15] ftrace: fix event alignment: kvm:kvm_hv_hypercall David Sharp
2010-12-04 1:49 ` Steven Rostedt
2010-12-04 8:11 ` Avi Kivity
2010-12-06 20:38 ` David Sharp
2010-12-07 9:22 ` Avi Kivity
2010-12-07 21:16 ` David Sharp
2010-12-08 9:18 ` Avi Kivity
2011-03-08 23:55 ` Steven Rostedt
2011-03-09 8:50 ` Avi Kivity
2011-03-09 12:54 ` Steven Rostedt
2011-03-09 13:01 ` Avi Kivity
2011-03-11 9:49 ` [tip:perf/core] tracing: Fix " tip-bot for David Sharp
2010-12-04 0:13 ` [PATCH 08/15] ftrace: fix event alignment: mce:mce_record David Sharp
2010-12-04 1:50 ` Steven Rostedt
2010-12-09 13:33 ` Frederic Weisbecker
2011-03-11 9:49 ` [tip:perf/core] tracing: Fix " tip-bot for David Sharp
2010-12-04 0:13 ` [PATCH 09/15] ftrace: fix event alignment: skb:kfree_skb David Sharp
2010-12-04 1:52 ` Steven Rostedt
2010-12-04 13:38 ` Neil Horman
2011-03-11 9:50 ` [tip:perf/core] tracing: Fix " tip-bot for David Sharp
2010-12-04 0:13 ` [PATCH 10/15] ftrace: fix event alignment: jbd2:* David Sharp
2010-12-04 1:52 ` Steven Rostedt
2011-03-09 0:03 ` Steven Rostedt
2011-03-09 0:31 ` Ted Ts'o
2011-03-09 0:41 ` Steven Rostedt
2010-12-04 0:13 ` [PATCH 11/15] ftrace: fix event alignment: ext4:* David Sharp
2010-12-04 1:53 ` Steven Rostedt
2011-03-09 0:04 ` Steven Rostedt
2010-12-04 0:13 ` [PATCH 12/15] trace_output.c: adjust conditional expression formatting David Sharp
2011-03-11 9:50 ` [tip:perf/core] tracing: Adjust conditional expression latency formatting tip-bot for David Sharp
2010-12-04 0:13 ` [PATCH 13/15] small_traces: Add config option to shrink trace events David Sharp
2010-12-04 1:56 ` Steven Rostedt
2010-12-04 2:33 ` David Sharp
2010-12-04 2:54 ` Steven Rostedt
2010-12-09 14:55 ` Frederic Weisbecker
2010-12-09 15:08 ` Steven Rostedt
2010-12-09 15:28 ` Frederic Weisbecker
2010-12-09 16:16 ` Mathieu Desnoyers
2011-03-09 0:23 ` Steven Rostedt
2010-12-04 0:13 ` [PATCH 14/15] small_traces: Remove trace output of large fields David Sharp
2010-12-04 0:13 ` [PATCH 15/15] small_traces: Remove 8 bytes from trace_entry David Sharp
2010-12-06 13:22 ` [Patch 00/15] Reduce tracing payload size Andi Kleen
2010-12-06 13:56 ` Ted Ts'o
2010-12-06 14:58 ` Andi Kleen
2010-12-06 16:17 ` Steven Rostedt [this message]
2010-12-06 16:31 ` Miguel Ojeda
2010-12-06 16:41 ` Andi Kleen
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