Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752142AbdFZW5m (ORCPT ); Mon, 26 Jun 2017 18:57:42 -0400 Received: from mga04.intel.com ([192.55.52.120]:11033 "EHLO mga04.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751498AbdFZWts (ORCPT ); Mon, 26 Jun 2017 18:49:48 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.39,397,1493708400"; d="scan'208";a="1164914881" From: Tom Zanussi To: rostedt@goodmis.org Cc: tglx@linutronix.de, mhiramat@kernel.org, namhyung@kernel.org, vedang.patel@intel.com, linux-kernel@vger.kernel.org, linux-rt-users@vger.kernel.org, Tom Zanussi Subject: [PATCH 03/32] ring-buffer: Add interface for setting absolute time stamps Date: Mon, 26 Jun 2017 17:49:04 -0500 Message-Id: <2e6714e525e62f54dd72d563c7d220be76f8f808.1498510759.git.tom.zanussi@linux.intel.com> 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: 3786 Lines: 118 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 --- include/linux/ring_buffer.h | 2 ++ kernel/trace/ring_buffer.c | 11 +++++++++++ kernel/trace/trace.c | 25 ++++++++++++++++++++++++- kernel/trace/trace.h | 2 ++ 4 files changed, 39 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 4ae268e..f544738 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 19ac208..da8cd51 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -2169,7 +2169,7 @@ 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 */ @@ -6079,6 +6079,29 @@ 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) +{ + mutex_lock(&trace_types_lock); + + 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->flags & TRACE_ARRAY_FL_GLOBAL && tr->max_buffer.buffer) + ring_buffer_set_time_stamp_abs(tr->max_buffer.buffer, abs); + tracing_reset_online_cpus(&tr->max_buffer); +#endif + + mutex_unlock(&trace_types_lock); + + return 0; +} + struct ftrace_buffer_info { struct trace_iterator iter; void *spare; diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 69a3ab3..155ad9a 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -281,6 +281,8 @@ 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