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Date: Fri, 24 Feb 2012 08:24:29 -0700 From: David Ahern <dsahern@...il.com> To: Stephane Eranian <eranian@...gle.com> CC: linux-kernel@...r.kernel.org, acme@...hat.com, peterz@...radead.org, mingo@...e.hu, ravitillo@....gov, khandual@...ux.vnet.ibm.com, asharma@...com, robert.richter@....com, ming.m.lin@...el.com, vweaver1@...s.utk.edu, andi@...stfloor.org Subject: Re: [PATCH] perf report: auto-detect branch stack sampling mode On 2/24/12 2:40 AM, Stephane Eranian wrote: > > This patch adds auto-detection of samples with taken branch stacks. > The auto-detection avoids having to specify the -b or --branch-stack > option on the cmdline. > > The patch adds a new feature bit HEADER_BRANCH_STACK to mark the > presence of branch stacks in samples. > > You can now do: > $ perf record -b any noploop 2 > $ perf report > # Events: 8K cycles > # > # Overhead Command Source Shared Object Source Symbol Target Shared Object Target Symbol > # ........ ....... .................... ................... .................... .................. > # > 91.56% noploop noploop [.] noploop noploop [.] noploop > 0.42% noploop [kernel.kallsyms] [k] __lock_acquire [kernel.kallsyms] [k] __lock_acquire > > > To force regular reporting based on the instruction address: > $ perf report --no-branch-stack > # > # Events: 2K cycles > # > # Overhead Command Shared Object Symbol > # ........ ....... ................. ............................... > # > 92.03% noploop noploop [.] noploop > 1.00% noploop [kernel.kallsyms] [k] lock_acquire > > > Signed-off-by: Stephane Eranian<eranian@...gle.com> > --- > > diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c > index 1c49d4e..5e833a2 100644 > --- a/tools/perf/builtin-record.c > +++ b/tools/perf/builtin-record.c > @@ -473,6 +473,9 @@ static int __cmd_record(struct perf_record *rec, int argc, const char **argv) > if (!have_tracepoints(&evsel_list->entries)) > perf_header__clear_feat(&session->header, HEADER_TRACE_INFO); > > + if (!rec->opts.branch_stack) > + perf_header__clear_feat(&session->header, HEADER_BRANCH_STACK); branch tracing is user requested on, so shouldn't feature default off and only be enabled when requested? David > + > if (!rec->file_new) { > err = perf_session__read_header(session, output); > if (err< 0) > diff --git a/tools/perf/builtin-report.c b/tools/perf/builtin-report.c > index 528789f..edd4289 100644 > --- a/tools/perf/builtin-report.c > +++ b/tools/perf/builtin-report.c > @@ -306,21 +306,14 @@ static int __cmd_report(struct perf_report *rep) > { > int ret = -EINVAL; > u64 nr_samples; > - struct perf_session *session; > struct perf_evsel *pos; > + struct perf_session *session = rep->session; > struct map *kernel_map; > struct kmap *kernel_kmap; > const char *help = "For a higher level overview, try: perf report --sort comm,dso"; > > signal(SIGINT, sig_handler); > > - session = perf_session__new(rep->input_name, O_RDONLY, > - rep->force, false,&rep->tool); > - if (session == NULL) > - return -ENOMEM; > - > - rep->session = session; > - > if (rep->cpu_list) { > ret = perf_session__cpu_bitmap(session, rep->cpu_list, > rep->cpu_bitmap); > @@ -489,7 +482,10 @@ parse_callchain_opt(const struct option *opt, const char *arg, int unset) > > int cmd_report(int argc, const char **argv, const char *prefix __used) > { > + struct perf_session *session; > struct stat st; > + bool has_br_stack; > + int ret = -1; > char callchain_default_opt[] = "fractal,0.5,callee"; > const char * const report_usage[] = { > "perf report [<options>]", > @@ -600,7 +596,23 @@ int cmd_report(int argc, const char **argv, const char *prefix __used) > report.input_name = "perf.data"; > } > > - if (sort__branch_mode) { > + session = perf_session__new(report.input_name, O_RDONLY, > + report.force, false,&report.tool); > + if (session == NULL) > + return -ENOMEM; > + > + report.session = session; > + > + has_br_stack = perf_header__has_feat(&session->header, > + HEADER_BRANCH_STACK); > + > + /* > + * if branch mode set by user via -b or --branch-stack > + * or not forced off by user (-no-branch-stack) user and present > + * in the file then we set branch mode > + */ > + if (sort__branch_mode || (sort__branch_mode == -1&& has_br_stack)) { > + sort__branch_mode = true; > if (use_browser) > fprintf(stderr, "Warning: TUI interface not supported" > " in branch mode\n"); > @@ -657,13 +669,13 @@ int cmd_report(int argc, const char **argv, const char *prefix __used) > } > > if (symbol__init()< 0) > - return -1; > + goto error; > > setup_sorting(report_usage, options); > > if (parent_pattern != default_parent_pattern) { > if (sort_dimension__add("parent")< 0) > - return -1; > + goto error; > > /* > * Only show the parent fields if we explicitly > @@ -685,5 +697,8 @@ int cmd_report(int argc, const char **argv, const char *prefix __used) > sort_entry__setup_elide(&sort_comm, symbol_conf.comm_list, "comm", stdout); > sort_entry__setup_elide(&sort_sym, symbol_conf.sym_list, "symbol", stdout); > > - return __cmd_report(&report); > + ret = __cmd_report(&report); > +error: > + perf_session__delete(session); > + return ret; > } > diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c > index c851495..c22491e 100644 > --- a/tools/perf/util/header.c > +++ b/tools/perf/util/header.c > @@ -1023,6 +1023,12 @@ static int write_cpuid(int fd, struct perf_header *h __used, > return do_write_string(fd, buffer); > } > > +static int write_branch_stack(int fd __used, struct perf_header *h __used, > + struct perf_evlist *evlist __used) > +{ > + return 0; > +} > + > static void print_hostname(struct perf_header *ph, int fd, FILE *fp) > { > char *str = do_read_string(fd, ph); > @@ -1315,6 +1321,12 @@ static void print_cpuid(struct perf_header *ph, int fd, FILE *fp) > free(str); > } > > +static void print_branch_stack(struct perf_header *ph __used, int fd __used, > + FILE *fp) > +{ > + fprintf(fp, "# contains samples with branch stacks\n"); > +} > + > static int __event_process_build_id(struct build_id_event *bev, > char *filename, > struct perf_session *session) > @@ -1519,6 +1531,7 @@ static const struct feature_ops feat_ops[HEADER_LAST_FEATURE] = { > FEAT_OPA(HEADER_CMDLINE, cmdline), > FEAT_OPF(HEADER_CPU_TOPOLOGY, cpu_topology), > FEAT_OPF(HEADER_NUMA_TOPOLOGY, numa_topology), > + FEAT_OPA(HEADER_BRANCH_STACK, branch_stack), > }; > > struct header_print_data { > diff --git a/tools/perf/util/header.h b/tools/perf/util/header.h > index e68f617..21a6be0 100644 > --- a/tools/perf/util/header.h > +++ b/tools/perf/util/header.h > @@ -27,7 +27,7 @@ enum { > HEADER_EVENT_DESC, > HEADER_CPU_TOPOLOGY, > HEADER_NUMA_TOPOLOGY, > - > + HEADER_BRANCH_STACK, > HEADER_LAST_FEATURE, > HEADER_FEAT_BITS = 256, > }; > diff --git a/tools/perf/util/sort.c b/tools/perf/util/sort.c > index 2739ed1..69d50c0 100644 > --- a/tools/perf/util/sort.c > +++ b/tools/perf/util/sort.c > @@ -8,7 +8,7 @@ const char default_sort_order[] = "comm,dso,symbol"; > const char *sort_order = default_sort_order; > int sort__need_collapse = 0; > int sort__has_parent = 0; > -bool sort__branch_mode; > +bool sort__branch_mode = -1; /* -1 = means not set */ > > enum sort_type sort__first_dimension; > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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