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Message-ID: <20151022075603.GA29953@krava.redhat.com>
Date: Thu, 22 Oct 2015 09:56:03 +0200
From: Jiri Olsa <jolsa@...hat.com>
To: Arnaldo Carvalho de Melo <acme@...nel.org>
Cc: Jiri Olsa <jolsa@...nel.org>, lkml <linux-kernel@...r.kernel.org>,
David Ahern <dsahern@...il.com>,
Ingo Molnar <mingo@...nel.org>,
Namhyung Kim <namhyung@...nel.org>,
Peter Zijlstra <a.p.zijlstra@...llo.nl>,
"Liang, Kan" <kan.liang@...el.com>
Subject: Re: [PATCH 05/57] perf tools: Add cpu_map event
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@...nel.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
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