Re: [PATCH 08/44] perf session: Add hooks to allow transparent decoding of AUX area tracing data

[Arnaldo Carvalho de Melo <acme@kernel.org>]

Em Thu, Apr 09, 2015 at 06:53:48PM +0300, Adrian Hunter escreveu:
> Hook into session processing so that AUX area decoding can
> synthesize events transparently to the tools.
> 
> The advantages of transparent decoding are that tools can be used
> directly with perf.data files containing AUX area tracing data,
> which is easier for the user and more efficient than having a
> separate decoding tool.
> 
> This will work as follows:
> 1. Tools will feed auxtrace events to the decoder using
> perf_tool->auxtrace() (support for that still to come).
> 2. The decoder can process side-band events as needed due
> to the auxtrace->process_event() hook.
> 3. The decoder can deliver synthesized events into the
> event stream using perf_session__deliver_synth_event().

So, here this clashes with work I'm doing to untie ordered_events from
perf_session, undoes it even, trying to decipher if this is really
needed...

- Arnaldo
 
> Note the expectation is that decoding will work on data that is
> time-ordered with respect to the per-cpu or per-thread contexts
> that were recorded.
 
> Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
> ---
>  tools/perf/util/auxtrace.h | 55 ++++++++++++++++++++++++++++++++++++++++++++++
>  tools/perf/util/session.c  | 54 ++++++++++++++++++++++++++++++++++++---------
>  tools/perf/util/session.h  |  3 +++
>  3 files changed, 102 insertions(+), 10 deletions(-)
> 
> diff --git a/tools/perf/util/auxtrace.h b/tools/perf/util/auxtrace.h
> index 7ab4850..199fc27 100644
> --- a/tools/perf/util/auxtrace.h
> +++ b/tools/perf/util/auxtrace.h
> @@ -23,6 +23,7 @@
>  #include <linux/types.h>
>  
>  #include "../perf.h"
> +#include "session.h"
>  
>  union perf_event;
>  struct perf_session;
> @@ -32,6 +33,24 @@ struct record_opts;
>  struct auxtrace_info_event;
>  
>  /**
> + * struct auxtrace - session callbacks to allow AUX area data decoding.
> + * @process_event: lets the decoder see all session events
> + * @flush_events: process any remaining data
> + * @free_events: free resources associated with event processing
> + * @free: free resources associated with the session
> + */
> +struct auxtrace {
> +	int (*process_event)(struct perf_session *session,
> +			     union perf_event *event,
> +			     struct perf_sample *sample,
> +			     struct perf_tool *tool);
> +	int (*flush_events)(struct perf_session *session,
> +			    struct perf_tool *tool);
> +	void (*free_events)(struct perf_session *session);
> +	void (*free)(struct perf_session *session);
> +};
> +
> +/**
>   * struct auxtrace_mmap - records an mmap of the auxtrace buffer.
>   * @base: address of mapped area
>   * @userpg: pointer to buffer's perf_event_mmap_page
> @@ -168,4 +187,40 @@ int perf_event__synthesize_auxtrace_info(struct auxtrace_record *itr,
>  					 struct perf_session *session,
>  					 perf_event__handler_t process);
>  
> +static inline int auxtrace__process_event(struct perf_session *session,
> +					  union perf_event *event,
> +					  struct perf_sample *sample,
> +					  struct perf_tool *tool)
> +{
> +	if (!session->auxtrace)
> +		return 0;
> +
> +	return session->auxtrace->process_event(session, event, sample, tool);
> +}
> +
> +static inline int auxtrace__flush_events(struct perf_session *session,
> +					 struct perf_tool *tool)
> +{
> +	if (!session->auxtrace)
> +		return 0;
> +
> +	return session->auxtrace->flush_events(session, tool);
> +}
> +
> +static inline void auxtrace__free_events(struct perf_session *session)
> +{
> +	if (!session->auxtrace)
> +		return;
> +
> +	return session->auxtrace->free_events(session);
> +}
> +
> +static inline void auxtrace__free(struct perf_session *session)
> +{
> +	if (!session->auxtrace)
> +		return;
> +
> +	return session->auxtrace->free(session);
> +}
> +
>  #endif
> diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
> index 18e4034..cf9d678 100644
> --- a/tools/perf/util/session.c
> +++ b/tools/perf/util/session.c
> @@ -15,12 +15,13 @@
>  #include "cpumap.h"
>  #include "perf_regs.h"
>  #include "asm/bug.h"
> +#include "auxtrace.h"
>  
> -static int machines__deliver_event(struct machines *machines,
> -				   struct perf_evlist *evlist,
> -				   union perf_event *event,
> -				   struct perf_sample *sample,
> -				   struct perf_tool *tool, u64 file_offset);
> +static int perf_session__deliver_event(struct perf_session *session,
> +				       union perf_event *event,
> +				       struct perf_sample *sample,
> +				       struct perf_tool *tool,
> +				       u64 file_offset);
>  
>  static int perf_session__open(struct perf_session *session)
>  {
> @@ -105,8 +106,8 @@ static int ordered_events__deliver_event(struct ordered_events *oe,
>  		return ret;
>  	}
>  
> -	return machines__deliver_event(&session->machines, session->evlist, event->event,
> -				       &sample, session->tool, event->file_offset);
> +	return perf_session__deliver_event(session, event->event, &sample,
> +					   session->tool, event->file_offset);
>  }
>  
>  struct perf_session *perf_session__new(struct perf_data_file *file,
> @@ -185,6 +186,7 @@ static void perf_session_env__delete(struct perf_session_env *env)
>  
>  void perf_session__delete(struct perf_session *session)
>  {
> +	auxtrace__free(session);
>  	perf_session__destroy_kernel_maps(session);
>  	perf_session__delete_threads(session);
>  	perf_session_env__delete(&session->header.env);
> @@ -1030,6 +1032,24 @@ static int machines__deliver_event(struct machines *machines,
>  	}
>  }
>  
> +static int perf_session__deliver_event(struct perf_session *session,
> +				       union perf_event *event,
> +				       struct perf_sample *sample,
> +				       struct perf_tool *tool,
> +				       u64 file_offset)
> +{
> +	int ret;
> +
> +	ret = auxtrace__process_event(session, event, sample, tool);
> +	if (ret < 0)
> +		return ret;
> +	if (ret > 0)
> +		return 0;
> +
> +	return machines__deliver_event(&session->machines, session->evlist,
> +				       event, sample, tool, file_offset);
> +}
> +
>  static s64 perf_session__process_user_event(struct perf_session *session,
>  					    union perf_event *event,
>  					    u64 file_offset)
> @@ -1190,8 +1210,8 @@ static s64 perf_session__process_event(struct perf_session *session,
>  			return ret;
>  	}
>  
> -	return machines__deliver_event(&session->machines, evlist, event,
> -				       &sample, tool, file_offset);
> +	return perf_session__deliver_event(session, event, &sample, tool,
> +					   file_offset);
>  }
>  
>  void perf_event_header__bswap(struct perf_event_header *hdr)
> @@ -1350,10 +1370,14 @@ more:
>  done:
>  	/* do the final flush for ordered samples */
>  	err = ordered_events__flush(oe, OE_FLUSH__FINAL);
> +	if (err)
> +		goto out_err;
> +	err = auxtrace__flush_events(session, tool);
>  out_err:
>  	free(buf);
>  	perf_session__warn_about_errors(session);
>  	ordered_events__free(&session->ordered_events);
> +	auxtrace__free_events(session);
>  	return err;
>  }
>  
> @@ -1496,10 +1520,14 @@ more:
>  out:
>  	/* do the final flush for ordered samples */
>  	err = ordered_events__flush(oe, OE_FLUSH__FINAL);
> +	if (err)
> +		goto out_err;
> +	err = auxtrace__flush_events(session, tool);
>  out_err:
>  	ui_progress__finish();
>  	perf_session__warn_about_errors(session);
>  	ordered_events__free(&session->ordered_events);
> +	auxtrace__free_events(session);
>  	session->one_mmap = false;
>  	return err;
>  }
> @@ -1582,7 +1610,13 @@ size_t perf_session__fprintf_dsos_buildid(struct perf_session *session, FILE *fp
>  
>  size_t perf_session__fprintf_nr_events(struct perf_session *session, FILE *fp)
>  {
> -	size_t ret = fprintf(fp, "Aggregated stats:\n");
> +	size_t ret;
> +	const char *msg = "";
> +
> +	if (perf_header__has_feat(&session->header, HEADER_AUXTRACE))
> +		msg = " (excludes AUX area (e.g. instruction trace) decoded / synthesized events)";
> +
> +	ret = fprintf(fp, "Aggregated stats:%s\n", msg);
>  
>  	ret += events_stats__fprintf(&session->evlist->stats, fp);
>  	return ret;
> diff --git a/tools/perf/util/session.h b/tools/perf/util/session.h
> index d5fa7b791..8a69d3b 100644
> --- a/tools/perf/util/session.h
> +++ b/tools/perf/util/session.h
> @@ -15,10 +15,13 @@
>  struct ip_callchain;
>  struct thread;
>  
> +struct auxtrace;
> +
>  struct perf_session {
>  	struct perf_header	header;
>  	struct machines		machines;
>  	struct perf_evlist	*evlist;
> +	struct auxtrace		*auxtrace;
>  	struct trace_event	tevent;
>  	bool			repipe;
>  	bool			one_mmap;
> -- 
> 1.9.1