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

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

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?

- 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