Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752579AbdIVUA6 (ORCPT ); Fri, 22 Sep 2017 16:00:58 -0400 Received: from mga05.intel.com ([192.55.52.43]:46077 "EHLO mga05.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751915AbdIVUA4 (ORCPT ); Fri, 22 Sep 2017 16:00:56 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.42,427,1500966000"; d="scan'208";a="1222520146" From: Tom Zanussi To: rostedt@goodmis.org Cc: tglx@linutronix.de, mhiramat@kernel.org, namhyung@kernel.org, vedang.patel@intel.com, bigeasy@linutronix.de, joel.opensrc@gmail.com, joelaf@google.com, mathieu.desnoyers@efficios.com, baohong.liu@intel.com, rajvi.jingar@intel.com, linux-kernel@vger.kernel.org, linux-rt-users@vger.kernel.org, Tom Zanussi Subject: [PATCH v3 03/33] ring-buffer: Add interface for setting absolute time stamps Date: Fri, 22 Sep 2017 14:59:43 -0500 Message-Id: X-Mailer: git-send-email 1.9.3 In-Reply-To: References: In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4199 Lines: 142 Define a new function, tracing_set_time_stamp_abs(), which can be used to enable or disable the use of absolute timestamps rather than time deltas for a trace array. This resets the buffer to prevent a mix of time deltas and absolute timestamps. Only the interface is added here; a subsequent patch will add the underlying implementation. Signed-off-by: Tom Zanussi Signed-off-by: Baohong Liu --- include/linux/ring_buffer.h | 2 ++ kernel/trace/ring_buffer.c | 11 +++++++++++ kernel/trace/trace.c | 40 +++++++++++++++++++++++++++++++++++++++- kernel/trace/trace.h | 3 +++ 4 files changed, 55 insertions(+), 1 deletion(-) diff --git a/include/linux/ring_buffer.h b/include/linux/ring_buffer.h index ee9b461..28e3472 100644 --- a/include/linux/ring_buffer.h +++ b/include/linux/ring_buffer.h @@ -180,6 +180,8 @@ void ring_buffer_normalize_time_stamp(struct ring_buffer *buffer, int cpu, u64 *ts); void ring_buffer_set_clock(struct ring_buffer *buffer, u64 (*clock)(void)); +void ring_buffer_set_time_stamp_abs(struct ring_buffer *buffer, bool abs); +bool ring_buffer_time_stamp_abs(struct ring_buffer *buffer); size_t ring_buffer_page_len(void *page); diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index f6ee9b1..1e5b75a 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -485,6 +485,7 @@ struct ring_buffer { u64 (*clock)(void); struct rb_irq_work irq_work; + bool time_stamp_abs; }; struct ring_buffer_iter { @@ -1379,6 +1380,16 @@ void ring_buffer_set_clock(struct ring_buffer *buffer, buffer->clock = clock; } +void ring_buffer_set_time_stamp_abs(struct ring_buffer *buffer, bool abs) +{ + buffer->time_stamp_abs = abs; +} + +bool ring_buffer_time_stamp_abs(struct ring_buffer *buffer) +{ + return buffer->time_stamp_abs; +} + static void rb_reset_cpu(struct ring_buffer_per_cpu *cpu_buffer); static inline unsigned long rb_page_entries(struct buffer_page *bpage) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index c203b4b..24af00a 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -2269,7 +2269,7 @@ struct ring_buffer_event * *current_rb = trace_file->tr->trace_buffer.buffer; - if ((trace_file->flags & + if (!ring_buffer_time_stamp_abs(*current_rb) && (trace_file->flags & (EVENT_FILE_FL_SOFT_DISABLED | EVENT_FILE_FL_FILTERED)) && (entry = this_cpu_read(trace_buffered_event))) { /* Try to use the per cpu buffer first */ @@ -6285,6 +6285,44 @@ static int tracing_clock_open(struct inode *inode, struct file *file) return ret; } +int tracing_set_time_stamp_abs(struct trace_array *tr, bool abs) +{ + int ret = 0; + + mutex_lock(&trace_types_lock); + + if (abs && tr->time_stamp_abs_ref++) + goto out; + + if (!abs) { + if (WARN_ON_ONCE(!tr->time_stamp_abs_ref)) { + ret = -EINVAL; + goto out; + } + + if (--tr->time_stamp_abs_ref) + goto out; + } + + ring_buffer_set_time_stamp_abs(tr->trace_buffer.buffer, abs); + + /* + * New timestamps may not be consistent with the previous setting. + * Reset the buffer so that it doesn't have incomparable timestamps. + */ + tracing_reset_online_cpus(&tr->trace_buffer); + +#ifdef CONFIG_TRACER_MAX_TRACE + if (tr->max_buffer.buffer) + ring_buffer_set_time_stamp_abs(tr->max_buffer.buffer, abs); + tracing_reset_online_cpus(&tr->max_buffer); +#endif + out: + mutex_unlock(&trace_types_lock); + + return ret; +} + struct ftrace_buffer_info { struct trace_iterator iter; void *spare; diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 61e2f35..d1e5d70 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -272,6 +272,7 @@ struct trace_array { /* function tracing enabled */ int function_enabled; #endif + int time_stamp_abs_ref; }; enum { @@ -285,6 +286,8 @@ enum { extern int trace_array_get(struct trace_array *tr); extern void trace_array_put(struct trace_array *tr); +extern int tracing_set_time_stamp_abs(struct trace_array *tr, bool abs); + /* * The global tracer (top) should be the first trace array added, * but we check the flag anyway. -- 1.9.3