From: Li Zefan <lizf@cn.fujitsu.com>
To: Ingo Molnar <mingo@elte.hu>
Cc: Steven Rostedt <rostedt@goodmis.org>,
Frederic Weisbecker <fweisbec@gmail.com>,
LKML <linux-kernel@vger.kernel.org>
Subject: [PATCH] tracing/events: change the type of __str_loc_item to unsigned short
Date: Thu, 21 May 2009 13:59:18 +0800 [thread overview]
Message-ID: <4A14EDB6.2050507@cn.fujitsu.com> (raw)
When defining a dynamic size string, we add __str_loc_##item to the
trace entry, and it stores the location of the actual string in
entry->_str_data[]
'unsigned short' should be sufficient to store this information, thus
we save 2 bytes per dyn-size string in the ring buffer.
[ Impact: reduce memory occupied by dyn-size strings in ring buffer ]
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
---
include/trace/ftrace.h | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/include/trace/ftrace.h b/include/trace/ftrace.h
index edb02bc..b5ff2e8 100644
--- a/include/trace/ftrace.h
+++ b/include/trace/ftrace.h
@@ -25,7 +25,7 @@
#define __field(type, item) type item;
#undef __string
-#define __string(item, src) int __str_loc_##item;
+#define __string(item, src) unsigned short __str_loc_##item;
#undef TP_STRUCT__entry
#define TP_STRUCT__entry(args...) args
-- 1.5.4.rc3
next reply other threads:[~2009-05-21 5:58 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-05-21 5:59 Li Zefan [this message]
2009-05-24 20:31 ` [PATCH] tracing/events: change the type of __str_loc_item to unsigned short Frederic Weisbecker
2009-05-27 22:34 ` [tip:tracing/core] " tip-bot for Li Zefan
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