From: Steven Rostedt <rostedt@goodmis.org>
To: linux-kernel@vger.kernel.org
Cc: Ingo Molnar <mingo@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Subject: [for-next][PATCH 14/18] ring-buffer: Mark the !tail (crossing a page) as unlikely
Date: Thu, 02 Jul 2020 17:58:26 -0400 [thread overview]
Message-ID: <20200702215833.563578523@goodmis.org> (raw)
In-Reply-To: 20200702215812.428188663@goodmis.org
From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>
It is the uncommon case where an event crosses a sub buffer boundary (page)
mark that check at the end of reserving an event as unlikely.
Suggested-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
kernel/trace/ring_buffer.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index ed1941304f69..888bc9177937 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -3260,7 +3260,7 @@ __rb_reserve_next(struct ring_buffer_per_cpu *cpu_buffer,
* If this is the first commit on the page, then update
* its timestamp.
*/
- if (!tail)
+ if (unlikely(!tail))
tail_page->page->time_stamp = info->ts;
/* account for these added bytes */
--
2.26.2
next prev parent reply other threads:[~2020-07-02 21:58 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-02 21:58 [for-next][PATCH 00/18] tracing: Updatse for 5.9 Steven Rostedt
2020-07-02 21:58 ` [for-next][PATCH 01/18] tracing: Only allow trace_array_printk() to be used by instances Steven Rostedt
2020-07-02 21:58 ` [for-next][PATCH 02/18] x86/ftrace: Make non direct case the default in ftrace_regs_caller Steven Rostedt
2020-07-02 21:58 ` [for-next][PATCH 03/18] x86/ftrace: Only have the builtin ftrace_regs_caller call direct hooks Steven Rostedt
2020-07-02 21:58 ` [for-next][PATCH 04/18] x86/ftrace: Do not jump to direct code in created trampolines Steven Rostedt
2020-07-03 8:10 ` Peter Zijlstra
2020-07-14 3:24 ` Steven Rostedt
2020-07-02 21:58 ` [for-next][PATCH 05/18] tracing: not necessary to undefine DEFINE_EVENT again Steven Rostedt
2020-07-02 21:58 ` [for-next][PATCH 06/18] tracing: not necessary re-define DEFINE_EVENT_PRINT Steven Rostedt
2020-07-02 21:58 ` [for-next][PATCH 07/18] tracing: define DEFINE_EVENT_PRINT not related to DEFINE_EVENT Steven Rostedt
2020-07-02 21:58 ` [for-next][PATCH 08/18] tracing: not necessary to define DEFINE_EVENT_PRINT to be empty again Steven Rostedt
2020-07-02 21:58 ` [for-next][PATCH 09/18] tracing: Move pipe reference to trace array instead of current_tracer Steven Rostedt
2020-07-31 19:33 ` dann frazier
2020-07-31 21:16 ` Steven Rostedt
2020-07-31 21:17 ` dann frazier
2020-07-02 21:58 ` [for-next][PATCH 10/18] ring-buffer: Have nested events still record running time stamp Steven Rostedt
2020-07-02 21:58 ` [for-next][PATCH 11/18] ring-buffer: Incorporate absolute timestamp into add_timestamp logic Steven Rostedt
2020-07-02 21:58 ` [for-next][PATCH 12/18] ring-buffer: Add rb_time_t 64 bit operations for speeding up 32 bit Steven Rostedt
2020-07-02 21:58 ` [for-next][PATCH 13/18] ring-buffer: speed up buffer resets by avoiding synchronize_rcu for each CPU Steven Rostedt
2020-07-02 21:58 ` Steven Rostedt [this message]
2020-07-02 21:58 ` [for-next][PATCH 15/18] ring-buffer: Consolidate add_timestamp to remove some branches Steven Rostedt
2020-07-02 21:58 ` [for-next][PATCH 16/18] ring-buffer: Move the add_timestamp into its own function Steven Rostedt
2020-07-02 21:58 ` [for-next][PATCH 17/18] ring-buffer: Call trace_clock_local() directly for RETPOLINE kernels Steven Rostedt
2020-07-02 21:58 ` [for-next][PATCH 18/18] ring-buffer: Do not trigger a WARN if clock going backwards is detected Steven Rostedt
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