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linux-next/tools/perf/util/parse-regs-options.c
Stephane Eranian bcc84ec65a 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 18:01:33 -03:00

72 lines
1.2 KiB
C

#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;
}