From bcc84ec65ad1bd9f777a1fade6f8e5e0c5808fa5 Mon Sep 17 00:00:00 2001 From: Stephane Eranian Date: Mon, 31 Aug 2015 18:41:12 +0200 Subject: [PATCH] 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 Tested-by: Arnaldo Carvalho de Melo Cc: Adrian Hunter Cc: Andi Kleen Cc: David Ahern Cc: Jiri Olsa Cc: Kan Liang Cc: Namhyung Kim Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/1441039273-16260-4-git-send-email-eranian@google.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/Documentation/perf-record.txt | 6 +- tools/perf/builtin-record.c | 7 ++- tools/perf/perf.h | 2 +- tools/perf/util/Build | 1 + tools/perf/util/evsel.c | 2 +- tools/perf/util/parse-regs-options.c | 71 ++++++++++++++++++++++++ tools/perf/util/parse-regs-options.h | 5 ++ 7 files changed, 89 insertions(+), 5 deletions(-) create mode 100644 tools/perf/util/parse-regs-options.c create mode 100644 tools/perf/util/parse-regs-options.h diff --git a/tools/perf/Documentation/perf-record.txt b/tools/perf/Documentation/perf-record.txt index 347a27322ed8..2e9ce77b5e14 100644 --- a/tools/perf/Documentation/perf-record.txt +++ b/tools/perf/Documentation/perf-record.txt @@ -276,7 +276,11 @@ filter out the startup phase of the program, which is often very different. --intr-regs:: Capture machine state (registers) at interrupt, i.e., on counter overflows for each sample. List of captured registers depends on the architecture. This option -is off by default. +is off by default. It is possible to select the registers to sample using their +symbolic names, e.g. on x86, ax, si. To list the available registers use +--intr-regs=\?. To name registers, pass a comma separated list such as +--intr-regs=ax,bx. The list of register is architecture dependent. + --running-time:: Record running and enabled time for read events (:S) diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c index 1d14f382f614..142eeb341b29 100644 --- a/tools/perf/builtin-record.c +++ b/tools/perf/builtin-record.c @@ -27,8 +27,10 @@ #include "util/cpumap.h" #include "util/thread_map.h" #include "util/data.h" +#include "util/perf_regs.h" #include "util/auxtrace.h" #include "util/parse-branch-options.h" +#include "util/parse-regs-options.h" #include #include @@ -1080,8 +1082,9 @@ struct option __record_options[] = { "sample transaction flags (special events only)"), OPT_BOOLEAN(0, "per-thread", &record.opts.target.per_thread, "use per-thread mmaps"), - OPT_BOOLEAN('I', "intr-regs", &record.opts.sample_intr_regs, - "Sample machine registers on interrupt"), + OPT_CALLBACK_OPTARG('I', "intr-regs", &record.opts.sample_intr_regs, NULL, "any register", + "sample selected machine registers on interrupt," + " use -I ? to list register names", parse_regs), OPT_BOOLEAN(0, "running-time", &record.opts.running_time, "Record running/enabled time of read (:S) events"), OPT_CALLBACK('k', "clockid", &record.opts, diff --git a/tools/perf/perf.h b/tools/perf/perf.h index cccb4cf575d3..90129accffbe 100644 --- a/tools/perf/perf.h +++ b/tools/perf/perf.h @@ -54,7 +54,6 @@ struct record_opts { bool sample_time_set; bool callgraph_set; bool period; - bool sample_intr_regs; bool running_time; bool full_auxtrace; bool auxtrace_snapshot_mode; @@ -64,6 +63,7 @@ struct record_opts { unsigned int auxtrace_mmap_pages; unsigned int user_freq; u64 branch_stack; + u64 sample_intr_regs; u64 default_interval; u64 user_interval; size_t auxtrace_snapshot_size; diff --git a/tools/perf/util/Build b/tools/perf/util/Build index e79e4522368a..349bc96ca1fe 100644 --- a/tools/perf/util/Build +++ b/tools/perf/util/Build @@ -83,6 +83,7 @@ libperf-$(CONFIG_AUXTRACE) += intel-pt-decoder/ libperf-$(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 bac25f41a751..c53f79123b37 100644 --- a/tools/perf/util/evsel.c +++ b/tools/perf/util/evsel.c @@ -787,7 +787,7 @@ void perf_evsel__config(struct perf_evsel *evsel, struct record_opts *opts) 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 000000000000..4f2c1c255d81 --- /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 000000000000..7d762b188007 --- /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 */