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>
diff --git a/tools/perf/util/Build b/tools/perf/util/Build
index e79e452..349bc96 100644
--- a/tools/perf/util/Build
+++ b/tools/perf/util/Build
@@ -83,6 +83,7 @@
libperf-$(CONFIG_AUXTRACE) += intel-pt.o
libperf-$(CONFIG_AUXTRACE) += intel-bts.o
libperf-y += parse-branch-options.o
+libperf-y += parse-regs-options.o
libperf-$(CONFIG_LIBELF) += symbol-elf.o
libperf-$(CONFIG_LIBELF) += probe-file.o
diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index bac25f4..c53f791 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -787,7 +787,7 @@
perf_evsel__config_callgraph(evsel, opts, &callchain_param);
if (opts->sample_intr_regs) {
- attr->sample_regs_intr = PERF_REGS_MASK;
+ attr->sample_regs_intr = opts->sample_intr_regs;
perf_evsel__set_sample_bit(evsel, REGS_INTR);
}
diff --git a/tools/perf/util/parse-regs-options.c b/tools/perf/util/parse-regs-options.c
new file mode 100644
index 0000000..4f2c1c2
--- /dev/null
+++ b/tools/perf/util/parse-regs-options.c
@@ -0,0 +1,71 @@
+#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;
+}
diff --git a/tools/perf/util/parse-regs-options.h b/tools/perf/util/parse-regs-options.h
new file mode 100644
index 0000000..7d762b1
--- /dev/null
+++ b/tools/perf/util/parse-regs-options.h
@@ -0,0 +1,5 @@
+#ifndef _PERF_PARSE_REGS_OPTIONS_H
+#define _PERF_PARSE_REGS_OPTIONS_H 1
+struct option;
+int parse_regs(const struct option *opt, const char *str, int unset);
+#endif /* _PERF_PARSE_REGS_OPTIONS_H */