Re: [PATCH 05/57] perf tools: Add cpu_map event

[Jiri Olsa <jolsa@redhat.com>]

On Mon, Oct 19, 2015 at 05:45:02PM -0300, Arnaldo Carvalho de Melo wrote:
> Em Fri, Oct 16, 2015 at 12:40:40PM +0200, Jiri Olsa escreveu:
> > Adding cpu_map event to pass/store cpu maps
> > as data in pipe/perf.data.
> > 
> > We store maps in 2 formats:
> >   - list of cpus
> >   - mask of cpus
> > 
> > The format that takes less space is selected
> > transparently in following patch.
> > 
> > The interface is made generic, so we could add
> > cpumap event data into another event in following
> > patches.
> 
> Hey, perf_event_header.size is u16, so max is 65535, which with each cpu
> taking 8 bytes... We this we can't support > ~8190 CPUs with
> PERF_CPU_MAP__CPUS.
> 
> Do we really need to use u64 for each CPU entry?

64 bits for cpu number should be ok for future ;-)

as I stated above there are 2 ways to save cpu map
  - list od cpus
  - mask of cpus

and the one taking less bytes is chosen.. but I agree
8 bytes for cpu number is little too much.. will change

jirka

> 
> - Arnaldo
>  
> > Link: http://lkml.kernel.org/n/tip-tomgwwohnuxvvalwu4znaa2o@git.kernel.org
> > Signed-off-by: Jiri Olsa <jolsa@kernel.org>
> > ---
> >  tools/perf/util/event.c   |  1 +
> >  tools/perf/util/event.h   | 28 ++++++++++++++++++++++++++
> >  tools/perf/util/session.c | 50 +++++++++++++++++++++++++++++++++++++++++++++++
> >  tools/perf/util/tool.h    |  3 ++-
> >  4 files changed, 81 insertions(+), 1 deletion(-)
> > 
> > diff --git a/tools/perf/util/event.c b/tools/perf/util/event.c
> > index ec2965b139a4..c05f4b036069 100644
> > --- a/tools/perf/util/event.c
> > +++ b/tools/perf/util/event.c
> > @@ -38,6 +38,7 @@ static const char *perf_event__names[] = {
> >  	[PERF_RECORD_AUXTRACE]			= "AUXTRACE",
> >  	[PERF_RECORD_AUXTRACE_ERROR]		= "AUXTRACE_ERROR",
> >  	[PERF_RECORD_THREAD_MAP]		= "THREAD_MAP",
> > +	[PERF_RECORD_CPU_MAP]			= "CPU_MAP",
> >  };
> >  
> >  const char *perf_event__name(unsigned int id)
> > diff --git a/tools/perf/util/event.h b/tools/perf/util/event.h
> > index 75157f3b16fb..7dcbd7f5b68c 100644
> > --- a/tools/perf/util/event.h
> > +++ b/tools/perf/util/event.h
> > @@ -227,6 +227,7 @@ enum perf_user_event_type { /* above any possible kernel type */
> >  	PERF_RECORD_AUXTRACE			= 71,
> >  	PERF_RECORD_AUXTRACE_ERROR		= 72,
> >  	PERF_RECORD_THREAD_MAP			= 73,
> > +	PERF_RECORD_CPU_MAP			= 74,
> >  	PERF_RECORD_HEADER_MAX
> >  };
> >  
> > @@ -271,6 +272,32 @@ struct events_stats {
> >  	u32 nr_proc_map_timeout;
> >  };
> >  
> > +enum {
> > +	PERF_CPU_MAP__CPUS = 0,
> > +	PERF_CPU_MAP__MASK = 1,
> > +};
> > +
> > +struct cpu_map_data_cpus {
> > +	u64	nr;
> > +	u64	cpu[];
> > +};
> > +
> > +struct cpu_map_data_mask {
> > +	u64	nr;
> > +	u64	long_size;
> > +	unsigned long mask[];
> > +};
> > +
> > +struct cpu_map_data {
> > +	u64	type;
> > +	char	data[];
> > +};
> > +
> > +struct cpu_map_event {
> > +	struct perf_event_header	header;
> > +	struct cpu_map_data		data;
> > +};
> > +
> >  struct attr_event {
> >  	struct perf_event_header header;
> >  	struct perf_event_attr attr;
> > @@ -391,6 +418,7 @@ union perf_event {
> >  	struct itrace_start_event	itrace_start;
> >  	struct context_switch_event	context_switch;
> >  	struct thread_map_event		thread_map;
> > +	struct cpu_map_event		cpu_map;
> >  };
> >  
> >  void perf_event__print_totals(void);
> > diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
> > index ec1ecd31003b..f4554bc43cce 100644
> > --- a/tools/perf/util/session.c
> > +++ b/tools/perf/util/session.c
> > @@ -306,6 +306,15 @@ int process_event_thread_map_stub(struct perf_tool *tool __maybe_unused,
> >  	return 0;
> >  }
> >  
> > +static
> > +int process_event_cpu_map_stub(struct perf_tool *tool __maybe_unused,
> > +			       union perf_event *event __maybe_unused,
> > +			       struct perf_session *session __maybe_unused)
> > +{
> > +	dump_printf(": unhandled!\n");
> > +	return 0;
> > +}
> > +
> >  void perf_tool__fill_defaults(struct perf_tool *tool)
> >  {
> >  	if (tool->sample == NULL)
> > @@ -358,6 +367,8 @@ void perf_tool__fill_defaults(struct perf_tool *tool)
> >  		tool->auxtrace_error = process_event_auxtrace_error_stub;
> >  	if (tool->thread_map == NULL)
> >  		tool->thread_map = process_event_thread_map_stub;
> > +	if (tool->cpu_map == NULL)
> > +		tool->cpu_map = process_event_cpu_map_stub;
> >  }
> >  
> >  static void swap_sample_id_all(union perf_event *event, void *data)
> > @@ -639,6 +650,42 @@ static void perf_event__thread_map_swap(union perf_event *event,
> >  		event->thread_map.data[i].pid = bswap_64(event->thread_map.data[i].pid);
> >  }
> >  
> > +static void perf_event__cpu_map_swap(union perf_event *event,
> > +				     bool sample_id_all __maybe_unused)
> > +{
> > +	struct cpu_map_data *data = &event->cpu_map.data;
> > +	struct cpu_map_data_cpus *cpus;
> > +	struct cpu_map_data_mask *mask;
> > +	unsigned i;
> > +
> > +	data->type = bswap_64(data->type);
> > +
> > +	switch (data->type) {
> > +	case PERF_CPU_MAP__CPUS:
> > +		cpus = (struct cpu_map_data_cpus*) data->data;
> > +
> > +		cpus->nr = bswap_64(cpus->nr);
> > +
> > +		for (i = 0; i < cpus->nr; i++)
> > +			cpus->cpu[i] = bswap_64(cpus->cpu[i]);
> > +		break;
> > +	case PERF_CPU_MAP__MASK:
> > +		mask = (struct cpu_map_data_mask*) data->data;
> > +
> > +		mask->nr = bswap_64(mask->nr);
> > +		mask->long_size = bswap_64(mask->long_size);
> > +
> > +		switch (mask->long_size) {
> > +		case 4: mem_bswap_32(&mask->mask, mask->nr); break;
> > +		case 8: mem_bswap_64(&mask->mask, mask->nr); break;
> > +		default:
> > +			pr_err("cpu_map swap: unsupported long size\n");
> > +		}
> > +	default:
> > +		break;
> > +	}
> > +}
> > +
> >  typedef void (*perf_event__swap_op)(union perf_event *event,
> >  				    bool sample_id_all);
> >  
> > @@ -667,6 +714,7 @@ static perf_event__swap_op perf_event__swap_ops[] = {
> >  	[PERF_RECORD_AUXTRACE]		  = perf_event__auxtrace_swap,
> >  	[PERF_RECORD_AUXTRACE_ERROR]	  = perf_event__auxtrace_error_swap,
> >  	[PERF_RECORD_THREAD_MAP]	  = perf_event__thread_map_swap,
> > +	[PERF_RECORD_CPU_MAP]		  = perf_event__cpu_map_swap,
> >  	[PERF_RECORD_HEADER_MAX]	  = NULL,
> >  };
> >  
> > @@ -1205,6 +1253,8 @@ static s64 perf_session__process_user_event(struct perf_session *session,
> >  		return tool->auxtrace_error(tool, event, session);
> >  	case PERF_RECORD_THREAD_MAP:
> >  		return tool->thread_map(tool, event, session);
> > +	case PERF_RECORD_CPU_MAP:
> > +		return tool->cpu_map(tool, event, session);
> >  	default:
> >  		return -EINVAL;
> >  	}
> > diff --git a/tools/perf/util/tool.h b/tools/perf/util/tool.h
> > index 1af4774960c3..9e5925c78519 100644
> > --- a/tools/perf/util/tool.h
> > +++ b/tools/perf/util/tool.h
> > @@ -56,7 +56,8 @@ struct perf_tool {
> >  			id_index,
> >  			auxtrace_info,
> >  			auxtrace_error,
> > -			thread_map;
> > +			thread_map,
> > +			cpu_map;
> >  	event_op3	auxtrace;
> >  	bool		ordered_events;
> >  	bool		ordering_requires_timestamps;
> > -- 
> > 2.4.3