Re: [PATCH perf/core v11 07/20] perf probe: Add --cache option to cache the probe definitions

Arnaldo Carvalho de Melo
2016-06-15T17:39:17Z

Em Wed, Jun 15, 2016 at 12:28:40PM +0900, Masami Hiramatsu escreveu:
> From: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
>
> Add --cache option to cache the probe definitions. This
> just saves the result of the dwarf analysis to probe cache.

So, I applied up to this patch and will test build and send to Ingo
today, but from this point on I think you should provide usage examples,
i.e. use the options introduced, showing what effects it has on
the cache, etc.

- Arnaldo

> Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
> Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
> ---
> Changes in v11:
> - Check failure of probe_cache operations and warn it.
> Changes in v10:
> - Split into 5 subpatches.
> Changes in v6:
> - Remove unneeded O_APPEND from open(). (Thanks Namhyung!)
> - Fix to check the return value of probe_cache_entry__new and strdup.(ditto)
> Changes in v5:
> - Move probe_cache* definitions. (code cleanup)
>
> Changes in v4:
> - Remove cache saving failure message.
> ---
> tools/perf/Documentation/perf-probe.txt | 4 ++++
> tools/perf/builtin-probe.c | 1 +
> tools/perf/util/probe-event.c | 9 +++++++++
> tools/perf/util/probe-event.h | 1 +
> 4 files changed, 15 insertions(+)
>
> diff --git a/tools/perf/Documentation/perf-probe.txt b/tools/perf/Documentation/perf-probe.txt
> index 3a8a9ba..947db6f 100644
> --- a/tools/perf/Documentation/perf-probe.txt
> +++ b/tools/perf/Documentation/perf-probe.txt
> @@ -109,6 +109,10 @@ OPTIONS
> Dry run. With this option, --add and --del doesn't execute actual
> adding and removal operations.
>
> +--cache::
> + Cache the probes (with --add option). Any events which successfully added
> + are also stored in the cache file.
> +
> --max-probes=NUM::
> Set the maximum number of probe points for an event. Default is 128.
>
> diff --git a/tools/perf/builtin-probe.c b/tools/perf/builtin-probe.c
> index 9af859b..6d7ab431 100644
> --- a/tools/perf/builtin-probe.c
> +++ b/tools/perf/builtin-probe.c
> @@ -512,6 +512,7 @@ __cmd_probe(int argc, const char **argv, const char *prefix __maybe_unused)
> "Enable symbol demangling"),
> OPT_BOOLEAN(0, "demangle-kernel", &symbol_conf.demangle_kernel,
> "Enable kernel symbol demangling"),
> + OPT_BOOLEAN(0, "cache", &probe_conf.cache, "Manipulate probe cache"),
> OPT_END()
> };
> int ret;
> diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
> index cbc8a8b..084756c 100644
> --- a/tools/perf/util/probe-event.c
> +++ b/tools/perf/util/probe-event.c
> @@ -2514,6 +2514,7 @@ static int __add_probe_trace_events(struct perf_probe_event *pev,
> {
> int i, fd, ret;
> struct probe_trace_event *tev = NULL;
> + struct probe_cache *cache = NULL;
> struct strlist *namelist;
>
> fd = probe_file__open(PF_FL_RW | (pev->uprobes ? PF_FL_UPROBE : 0));
> @@ -2555,6 +2556,14 @@ static int __add_probe_trace_events(struct perf_probe_event *pev,
> }
> if (ret == -EINVAL && pev->uprobes)
> warn_uprobe_event_compat(tev);
> + if (ret == 0 && probe_conf.cache) {
> + cache = probe_cache__new(pev->target);
> + if (!cache ||
> + probe_cache__add_entry(cache, pev, tevs, ntevs) < 0 ||
> + probe_cache__commit(cache) < 0)
> + pr_warning("Failed to add event to probe cache\n");
> + probe_cache__delete(cache);
> + }
>
> strlist__delete(namelist);
> close_out:
> diff --git a/tools/perf/util/probe-event.h b/tools/perf/util/probe-event.h
> index 0b024ba..432b690 100644
> --- a/tools/perf/util/probe-event.h
> +++ b/tools/perf/util/probe-event.h
> @@ -12,6 +12,7 @@ struct probe_conf {
> bool show_location_range;
> bool force_add;
> bool no_inlines;
> + bool cache;
> int max_probes;
> };
> extern struct probe_conf probe_conf;