Re: [PATCH 09/44] perf session: Add instruction tracing options

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

Em Wed, Apr 22, 2015 at 09:23:09AM +0300, Adrian Hunter escreveu:
> On 21/04/15 17:50, Arnaldo Carvalho de Melo wrote:
> > Em Thu, Apr 09, 2015 at 06:53:49PM +0300, Adrian Hunter escreveu:
> > 
> >> It is assumed that AUX area decoding will synthesize events for
> >> consumption by other tools.  At this time, the main use of AUX area
> >> tracing will be to capture instruction trace (aka processor trace)
> >> data.  The nature of instruction tracing suggests the initial
> >> inclusion of options for "instructions" and "branches" events, but
> >> more could be added as needed.
> >  
> >> +++ b/tools/perf/util/auxtrace.c
> >> @@ -37,6 +37,7 @@
> >>  
> >>  #include "event.h"
> >>  #include "debug.h"
> >> +#include "parse-options.h"
> >>  
> >>  int auxtrace_mmap__mmap(struct auxtrace_mmap *mm,
> >>  			struct auxtrace_mmap_params *mp,
> >> @@ -200,6 +201,136 @@ out_free:
> >>  	return err;
> >>  }
> >>  
> >> +#define PERF_ITRACE_DEFAULT_PERIOD_TYPE		PERF_ITRACE_PERIOD_NANOSECS
> >> +#define PERF_ITRACE_DEFAULT_PERIOD		100000
> >> +#define PERF_ITRACE_DEFAULT_CALLCHAIN_SZ	16
> >> +#define PERF_ITRACE_MAX_CALLCHAIN_SZ		1024
> >> +
> >> +void itrace_synth_opts__set_default(struct itrace_synth_opts *synth_opts)
> >> +{
> >> +	synth_opts->instructions = true;
> >> +	synth_opts->branches = true;
> >> +	synth_opts->errors = true;
> >> +	synth_opts->period_type = PERF_ITRACE_DEFAULT_PERIOD_TYPE;
> >> +	synth_opts->period = PERF_ITRACE_DEFAULT_PERIOD;
> >> +	synth_opts->callchain_sz = PERF_ITRACE_DEFAULT_CALLCHAIN_SZ;
> >> +}
> >> +
> >> +int itrace_parse_synth_opts(const struct option *opt, const char *str,
> >> +			    int unset)
> >> +{
> >> +	struct itrace_synth_opts *synth_opts = opt->value;
> >> +	const char *p;
> >> +	char *endptr;
> >> +
> >> +	synth_opts->set = true;
> >> +
> >> +	if (unset) {
> >> +		synth_opts->dont_decode = true;
> >> +		return 0;
> >> +	}
> >> +
> >> +	if (!str) {
> >> +		itrace_synth_opts__set_default(synth_opts);
> >> +		return 0;
> >> +	}
> >> +
> >> +	for (p = str; *p;) {
> >> +		switch (*p++) {
> >> +		case 'i':
> >> +			synth_opts->instructions = true;
> > 
> > Is this documented anywhere? I.e. examples for setting up this synth
> > ops?
> 
> They are documented for each tool that uses them:
> 	Documentation/perf-script.txt
> 	Documentation/perf-record.txt
> and also in:
> 	Documentation/intel-pt.txt

That comes later in the patchkit, right? I am ammending this patch to
put a reference to these files, which ammeliorates the current
situation, but people doing bisects will scratch their heads...

- Arnaldo