From: "Ted Ts'o" <tytso@mit.edu>
To: Andi Kleen <andi@firstfloor.org>
Cc: David Sharp <dhsharp@google.com>,
rostedt@goodmis.org, linux-kernel@vger.kernel.org,
mrubin@google.com
Subject: Re: [Patch 00/15] Reduce tracing payload size.
Date: Mon, 6 Dec 2010 08:56:37 -0500 [thread overview]
Message-ID: <20101206135637.GC8135@thunk.org> (raw)
In-Reply-To: <878w03t4sn.fsf@basil.nowhere.org>
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
can shrink the trace events by being more careful about unnecessary
padding, and not logging fields that aren't needed, it's all win....
The problem of course with the latter is that different people will
have disagreements about what is needed or not. And even adding
conditionals will slow down the tracing hotpath.
- Ted
next prev parent reply other threads:[~2010-12-06 13:56 UTC|newest]
Thread overview: 74+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-12-04 0:13 [Patch 00/15] Reduce tracing payload size 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 [this message]
2010-12-06 14:58 ` Andi Kleen
2010-12-06 16:17 ` Steven Rostedt
2010-12-06 16:31 ` Miguel Ojeda
2010-12-06 16:41 ` Andi Kleen
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