Re: [PATCH 5/6] perf script: expose usage of the callchain db export via the python api

[Adrian Hunter]

On 28/04/16 11:19, Chris Phlipot wrote:
> This change allows python scripts to be able to utilize the recent
> changes to the db export api allowing the export of call_paths derived
> from sampled callchains. These call paths are also now associated with
> the samples from which they were derived.
> 
> -This feature is enabled by setting "perf_db_export_callchains" to true
> 
> -When enabled, samples that have callchain information will have the
>     callchains exported via call_path_table
> 
> -The call_path_id field is added to sample_table to enable association of
>     samples with the corresponding callchain stored in the call paths
>     table. A call_path_id of 0 will be exported if there is no
>     corresponding callchain.
> 
> -When "perf_db_export_callchains" and "perf_db_export_calls" are both
>     set to True, the call path root data structure will be shared. This
>     prevents duplicating of data and call path ids that would result from
>     building two separate call path trees in memory.
> 
> -The call_return_processor structure definition was relocated to the header
>     file to make its contents visible to db-export.c. This enables the
>     sharing of call path trees between the two features, as mentioned
>     above.
> 
> This change is visible to python scripts using the python db export api.
> The change is backwards compatible with scripts written against the
> previous API, assuming that the scripts model the sample_table function
> after the one in export-to-postgresql.py script by allowing for additional
> arguments to be added in the future. ie. using *x as the final argument of
> the sample_table function.
> 
> Signed-off-by: Chris Phlipot <cphlipot0@xxxxxxxxx>

Acked-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>

> ---
>  .../util/scripting-engines/trace-event-python.c    | 35 ++++++++++++++++++++--
>  tools/perf/util/thread-stack.c                     | 13 --------
>  tools/perf/util/thread-stack.h                     | 14 ++++++++-
>  3 files changed, 46 insertions(+), 16 deletions(-)
> 
> diff --git a/tools/perf/util/scripting-engines/trace-event-python.c b/tools/perf/util/scripting-engines/trace-event-python.c
> index 7bb8592..091bce6 100644
> --- a/tools/perf/util/scripting-engines/trace-event-python.c
> +++ b/tools/perf/util/scripting-engines/trace-event-python.c
> @@ -682,7 +682,7 @@ static int python_export_sample(struct db_export *dbe,
>  	struct tables *tables = container_of(dbe, struct tables, dbe);
>  	PyObject *t;
>  
> -	t = tuple_new(21);
> +	t = tuple_new(22);
>  
>  	tuple_set_u64(t, 0, es->db_id);
>  	tuple_set_u64(t, 1, es->evsel->db_id);
> @@ -705,6 +705,7 @@ static int python_export_sample(struct db_export *dbe,
>  	tuple_set_u64(t, 18, es->sample->data_src);
>  	tuple_set_s32(t, 19, es->sample->flags & PERF_BRANCH_MASK);
>  	tuple_set_s32(t, 20, !!(es->sample->flags & PERF_IP_FLAG_IN_TX));
> +	tuple_set_u64(t, 21, es->call_path_id);
>  
>  	call_object(tables->sample_handler, t, "sample_table");
>  
> @@ -999,8 +1000,10 @@ static void set_table_handlers(struct tables *tables)
>  {
>  	const char *perf_db_export_mode = "perf_db_export_mode";
>  	const char *perf_db_export_calls = "perf_db_export_calls";
> -	PyObject *db_export_mode, *db_export_calls;
> +	const char *perf_db_export_callchains = "perf_db_export_callchains";
> +	PyObject *db_export_mode, *db_export_calls, *db_export_callchains;
>  	bool export_calls = false;
> +	bool export_callchains = false;
>  	int ret;
>  
>  	memset(tables, 0, sizeof(struct tables));
> @@ -1017,6 +1020,7 @@ static void set_table_handlers(struct tables *tables)
>  	if (!ret)
>  		return;
>  
> +	/* handle export calls */
>  	tables->dbe.crp = NULL;
>  	db_export_calls = PyDict_GetItemString(main_dict, perf_db_export_calls);
>  	if (db_export_calls) {
> @@ -1034,6 +1038,33 @@ static void set_table_handlers(struct tables *tables)
>  			Py_FatalError("failed to create calls processor");
>  	}
>  
> +	/* handle export callchains */
> +	tables->dbe.cpr = NULL;
> +	db_export_callchains = PyDict_GetItemString(main_dict,
> +						    perf_db_export_callchains);
> +	if (db_export_callchains) {
> +		ret = PyObject_IsTrue(db_export_callchains);
> +		if (ret == -1)
> +			handler_call_die(perf_db_export_callchains);
> +		export_callchains = !!ret;
> +	}
> +
> +	if (export_callchains) {
> +		/*
> +		 * Attempt to use the call path root from the call return
> +		 * processor, if the call return processor is in use. Otherwise,
> +		 * we allocate a new call path root. This prevents exporting
> +		 * duplicate call path ids when both are in use simultaniously.
> +		 */
> +		if (tables->dbe.crp)
> +			tables->dbe.cpr = tables->dbe.crp->cpr;
> +		else
> +			tables->dbe.cpr = call_path_root__new();
> +
> +		if (!tables->dbe.cpr)
> +			Py_FatalError("failed to create calls processor");
> +	}
> +
>  	tables->db_export_mode = true;
>  	/*
>  	 * Reserve per symbol space for symbol->db_id via symbol__priv()
> diff --git a/tools/perf/util/thread-stack.c b/tools/perf/util/thread-stack.c
> index fc419a5..825086a 100644
> --- a/tools/perf/util/thread-stack.c
> +++ b/tools/perf/util/thread-stack.c
> @@ -25,19 +25,6 @@
>  #include "call-path.h"
>  #include "thread-stack.h"
>  
> -/**
> - * struct call_return_processor - provides a call-back to consume call-return
> - *                                information.
> - * @cpr: call path root
> - * @process: call-back that accepts call/return information
> - * @data: anonymous data for call-back
> - */
> -struct call_return_processor {
> -	struct call_path_root *cpr;
> -	int (*process)(struct call_return *cr, void *data);
> -	void *data;
> -};
> -
>  #define STACK_GROWTH 2048
>  
>  /**
> diff --git a/tools/perf/util/thread-stack.h b/tools/perf/util/thread-stack.h
> index ec9bedd..ad44c79 100644
> --- a/tools/perf/util/thread-stack.h
> +++ b/tools/perf/util/thread-stack.h
> @@ -25,7 +25,6 @@ struct comm;
>  struct ip_callchain;
>  struct symbol;
>  struct dso;
> -struct call_return_processor;
>  struct comm;
>  struct perf_sample;
>  struct addr_location;
> @@ -68,6 +67,19 @@ struct call_return {
>  	u32 flags;
>  };
>  
> +/**
> + * struct call_return_processor - provides a call-back to consume call-return
> + *                                information.
> + * @cpr: call path root
> + * @process: call-back that accepts call/return information
> + * @data: anonymous data for call-back
> + */
> +struct call_return_processor {
> +	struct call_path_root *cpr;
> +	int (*process)(struct call_return *cr, void *data);
> +	void *data;
> +};
> +
>  int thread_stack__event(struct thread *thread, u32 flags, u64 from_ip,
>  			u64 to_ip, u16 insn_len, u64 trace_nr);
>  void thread_stack__set_trace_nr(struct thread *thread, u64 trace_nr);
>