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>
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@ -276,7 +276,11 @@ filter out the startup phase of the program, which is often very different.
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--intr-regs::
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Capture machine state (registers) at interrupt, i.e., on counter overflows for
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each sample. List of captured registers depends on the architecture. This option
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is off by default.
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is off by default. It is possible to select the registers to sample using their
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symbolic names, e.g. on x86, ax, si. To list the available registers use
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--intr-regs=\?. To name registers, pass a comma separated list such as
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--intr-regs=ax,bx. The list of register is architecture dependent.
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--running-time::
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Record running and enabled time for read events (:S)
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@ -27,8 +27,10 @@
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#include "util/cpumap.h"
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#include "util/thread_map.h"
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#include "util/data.h"
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#include "util/perf_regs.h"
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#include "util/auxtrace.h"
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#include "util/parse-branch-options.h"
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#include "util/parse-regs-options.h"
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#include <unistd.h>
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#include <sched.h>
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@ -1080,8 +1082,9 @@ struct option __record_options[] = {
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"sample transaction flags (special events only)"),
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OPT_BOOLEAN(0, "per-thread", &record.opts.target.per_thread,
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"use per-thread mmaps"),
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OPT_BOOLEAN('I', "intr-regs", &record.opts.sample_intr_regs,
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"Sample machine registers on interrupt"),
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OPT_CALLBACK_OPTARG('I', "intr-regs", &record.opts.sample_intr_regs, NULL, "any register",
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"sample selected machine registers on interrupt,"
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" use -I ? to list register names", parse_regs),
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OPT_BOOLEAN(0, "running-time", &record.opts.running_time,
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"Record running/enabled time of read (:S) events"),
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OPT_CALLBACK('k', "clockid", &record.opts,
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@ -54,7 +54,6 @@ struct record_opts {
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bool sample_time_set;
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bool callgraph_set;
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bool period;
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bool sample_intr_regs;
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bool running_time;
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bool full_auxtrace;
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bool auxtrace_snapshot_mode;
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@ -64,6 +63,7 @@ struct record_opts {
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unsigned int auxtrace_mmap_pages;
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unsigned int user_freq;
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u64 branch_stack;
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u64 sample_intr_regs;
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u64 default_interval;
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u64 user_interval;
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size_t auxtrace_snapshot_size;
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@ -83,6 +83,7 @@ libperf-$(CONFIG_AUXTRACE) += intel-pt-decoder/
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libperf-$(CONFIG_AUXTRACE) += intel-pt.o
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libperf-$(CONFIG_AUXTRACE) += intel-bts.o
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libperf-y += parse-branch-options.o
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libperf-y += parse-regs-options.o
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libperf-$(CONFIG_LIBELF) += symbol-elf.o
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libperf-$(CONFIG_LIBELF) += probe-file.o
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@ -787,7 +787,7 @@ void perf_evsel__config(struct perf_evsel *evsel, struct record_opts *opts)
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perf_evsel__config_callgraph(evsel, opts, &callchain_param);
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if (opts->sample_intr_regs) {
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attr->sample_regs_intr = PERF_REGS_MASK;
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attr->sample_regs_intr = opts->sample_intr_regs;
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perf_evsel__set_sample_bit(evsel, REGS_INTR);
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}
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71
tools/perf/util/parse-regs-options.c
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71
tools/perf/util/parse-regs-options.c
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@ -0,0 +1,71 @@
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#include "perf.h"
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#include "util/util.h"
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#include "util/debug.h"
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#include "util/parse-options.h"
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#include "util/parse-regs-options.h"
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int
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parse_regs(const struct option *opt, const char *str, int unset)
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{
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uint64_t *mode = (uint64_t *)opt->value;
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const struct sample_reg *r;
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char *s, *os = NULL, *p;
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int ret = -1;
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if (unset)
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return 0;
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/*
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* cannot set it twice
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*/
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if (*mode)
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return -1;
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/* str may be NULL in case no arg is passed to -I */
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if (str) {
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/* because str is read-only */
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s = os = strdup(str);
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if (!s)
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return -1;
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for (;;) {
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p = strchr(s, ',');
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if (p)
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*p = '\0';
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if (!strcmp(s, "?")) {
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fprintf(stderr, "available registers: ");
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for (r = sample_reg_masks; r->name; r++) {
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fprintf(stderr, "%s ", r->name);
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}
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fputc('\n', stderr);
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/* just printing available regs */
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return -1;
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}
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for (r = sample_reg_masks; r->name; r++) {
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if (!strcasecmp(s, r->name))
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break;
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}
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if (!r->name) {
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ui__warning("unknown register %s,"
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" check man page\n", s);
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goto error;
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}
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*mode |= r->mask;
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if (!p)
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break;
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s = p + 1;
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}
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}
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ret = 0;
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/* default to all possible regs */
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if (*mode == 0)
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*mode = PERF_REGS_MASK;
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error:
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free(os);
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return ret;
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}
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5
tools/perf/util/parse-regs-options.h
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5
tools/perf/util/parse-regs-options.h
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@ -0,0 +1,5 @@
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#ifndef _PERF_PARSE_REGS_OPTIONS_H
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#define _PERF_PARSE_REGS_OPTIONS_H 1
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struct option;
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int parse_regs(const struct option *opt, const char *str, int unset);
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#endif /* _PERF_PARSE_REGS_OPTIONS_H */
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