linux/tools/perf/util/parse-regs-options.c

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perf record: Add ability to name registers to record This patch modifies the -I/--int-regs option to enablepassing the name of the registers to sample on interrupt. Registers can be specified by their symbolic names. For instance on x86, --intr-regs=ax,si. The motivation is to reduce the size of the perf.data file and the overhead of sampling by only collecting the registers useful to a specific analysis. For instance, for value profiling, sampling only the registers used to passed arguements to functions. With no parameter, the --intr-regs still records all possible registers based on the architecture. To name registers, it is necessary to use the long form of the option, i.e., --intr-regs: $ perf record --intr-regs=si,di,r8,r9 ..... To record any possible registers: $ perf record -I ..... $ perf report --intr-regs ... To display the register, one can use perf report -D To list the available registers: $ perf record --intr-regs=\? available registers: AX BX CX DX SI DI BP SP IP FLAGS CS SS R8 R9 R10 R11 R12 R13 R14 R15 Signed-off-by: Stephane Eranian <eranian@google.com> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: David Ahern <dsahern@gmail.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Kan Liang <kan.liang@intel.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/1441039273-16260-4-git-send-email-eranian@google.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-08-31 16:41:12 +00:00
#include "perf.h"
#include "util/util.h"
#include "util/debug.h"
#include "util/parse-options.h"
#include "util/parse-regs-options.h"
int
parse_regs(const struct option *opt, const char *str, int unset)
{
uint64_t *mode = (uint64_t *)opt->value;
const struct sample_reg *r;
char *s, *os = NULL, *p;
int ret = -1;
if (unset)
return 0;
/*
* cannot set it twice
*/
if (*mode)
return -1;
/* str may be NULL in case no arg is passed to -I */
if (str) {
/* because str is read-only */
s = os = strdup(str);
if (!s)
return -1;
for (;;) {
p = strchr(s, ',');
if (p)
*p = '\0';
if (!strcmp(s, "?")) {
fprintf(stderr, "available registers: ");
for (r = sample_reg_masks; r->name; r++) {
fprintf(stderr, "%s ", r->name);
}
fputc('\n', stderr);
/* just printing available regs */
return -1;
}
for (r = sample_reg_masks; r->name; r++) {
if (!strcasecmp(s, r->name))
break;
}
if (!r->name) {
ui__warning("unknown register %s,"
" check man page\n", s);
goto error;
}
*mode |= r->mask;
if (!p)
break;
s = p + 1;
}
}
ret = 0;
/* default to all possible regs */
if (*mode == 0)
*mode = PERF_REGS_MASK;
error:
free(os);
return ret;
}