From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751232AbdGNFZL (ORCPT ); Fri, 14 Jul 2017 01:25:11 -0400 Received: from LGEAMRELO11.lge.com ([156.147.23.51]:32981 "EHLO lgeamrelo11.lge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750786AbdGNFZK (ORCPT ); Fri, 14 Jul 2017 01:25:10 -0400 X-Original-SENDERIP: 156.147.1.125 X-Original-MAILFROM: namhyung@kernel.org X-Original-SENDERIP: 10.177.227.17 X-Original-MAILFROM: namhyung@kernel.org Date: Fri, 14 Jul 2017 14:25:05 +0900 From: Namhyung Kim To: Tom Zanussi Cc: rostedt@goodmis.org, tglx@linutronix.de, mhiramat@kernel.org, vedang.patel@intel.com, linux-kernel@vger.kernel.org, linux-rt-users@vger.kernel.org, kernel-team@lge.com Subject: Re: [PATCH 03/32] ring-buffer: Add interface for setting absolute time stamps Message-ID: <20170714052505.GA27035@sejong> References: <2e6714e525e62f54dd72d563c7d220be76f8f808.1498510759.git.tom.zanussi@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <2e6714e525e62f54dd72d563c7d220be76f8f808.1498510759.git.tom.zanussi@linux.intel.com> User-Agent: Mutt/1.8.3 (2017-05-23) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jun 26, 2017 at 05:49:04PM -0500, Tom Zanussi wrote: > 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); Why do you do this only for the global array? AFAIK instance arrays can have the max buffer too. Am I missing something? Thanks, Namhyung > +#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 >