From bdfebd848f2a14e639031a0b0e61d7c7ee5e5fd2 Mon Sep 17 00:00:00 2001 From: Roberto Agostino Vitillo Date: Thu, 9 Feb 2012 23:21:02 +0100 Subject: [PATCH] perf record: Add support for sampling taken branch This patch adds a new option to enable taken branch stack sampling, i.e., leverage the PERF_SAMPLE_BRANCH_STACK feature of perf_events. There is a new option to active this mode: -b. It is possible to pass a set of filters to select the type of branches to sample. The following filters are available: - any : any type of branches - any_call : any function call or system call - any_ret : any function return or system call return - any_ind : any indirect branch - u: only when the branch target is at the user level - k: only when the branch target is in the kernel - hv: only when the branch target is in the hypervisor Filters can be combined by passing a comma separated list to the option: $ perf record -b any_call,u -e cycles:u branchy Signed-off-by: Roberto Agostino Vitillo Signed-off-by: Stephane Eranian Cc: peterz@infradead.org Cc: acme@redhat.com Cc: robert.richter@amd.com Cc: ming.m.lin@intel.com Cc: andi@firstfloor.org Cc: asharma@fb.com Cc: vweaver1@eecs.utk.edu Cc: khandual@linux.vnet.ibm.com Cc: dsahern@gmail.com Link: http://lkml.kernel.org/r/1328826068-11713-13-git-send-email-eranian@google.com Signed-off-by: Ingo Molnar --- tools/perf/Documentation/perf-record.txt | 25 ++++++++ tools/perf/builtin-record.c | 74 ++++++++++++++++++++++++ tools/perf/perf.h | 1 + tools/perf/util/evsel.c | 4 ++ 4 files changed, 104 insertions(+) diff --git a/tools/perf/Documentation/perf-record.txt b/tools/perf/Documentation/perf-record.txt index a5766b4b0125..60bddaf0e5bd 100644 --- a/tools/perf/Documentation/perf-record.txt +++ b/tools/perf/Documentation/perf-record.txt @@ -152,6 +152,31 @@ an empty cgroup (monitor all the time) using, e.g., -G foo,,bar. Cgroups must ha corresponding events, i.e., they always refer to events defined earlier on the command line. +-b:: +--branch-stack:: +Enable taken branch stack sampling. Each sample captures a series of consecutive +taken branches. The number of branches captured with each sample depends on the +underlying hardware, the type of branches of interest, and the executed code. +It is possible to select the types of branches captured by enabling filters. The +following filters are defined: + + - any : any type of branches + - any_call: any function call or system call + - any_ret: any function return or system call return + - any_ind: any indirect branch + - u: only when the branch target is at the user level + - k: only when the branch target is in the kernel + - hv: only when the target is at the hypervisor level + ++ +At least one of any, any_call, any_ret, any_ind must be provided. The privilege levels may +be ommitted, in which case, the privilege levels of the associated event are applied to the +branch filter. Both kernel (k) and hypervisor (hv) privilege levels are subject to +permissions. When sampling on multiple events, branch stack sampling is enabled for all +the sampling events. The sampled branch type is the same for all events. +Note that taken branch sampling may not be available on all processors. +The various filters must be specified as a comma separated list: -b any_ret,u,k + SEE ALSO -------- linkperf:perf-stat[1], linkperf:perf-list[1] diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c index 75d230fef202..1c49d4e8767c 100644 --- a/tools/perf/builtin-record.c +++ b/tools/perf/builtin-record.c @@ -638,6 +638,77 @@ out_delete_session: return err; } +#define BRANCH_OPT(n, m) \ + { .name = n, .mode = (m) } + +#define BRANCH_END { .name = NULL } + +struct branch_mode { + const char *name; + int mode; +}; + +static const struct branch_mode branch_modes[] = { + BRANCH_OPT("u", PERF_SAMPLE_BRANCH_USER), + BRANCH_OPT("k", PERF_SAMPLE_BRANCH_KERNEL), + BRANCH_OPT("hv", PERF_SAMPLE_BRANCH_HV), + BRANCH_OPT("any", PERF_SAMPLE_BRANCH_ANY), + BRANCH_OPT("any_call", PERF_SAMPLE_BRANCH_ANY_CALL), + BRANCH_OPT("any_ret", PERF_SAMPLE_BRANCH_ANY_RETURN), + BRANCH_OPT("ind_call", PERF_SAMPLE_BRANCH_IND_CALL), + BRANCH_END +}; + +static int +parse_branch_stack(const struct option *opt, const char *str, int unset __used) +{ +#define ONLY_PLM \ + (PERF_SAMPLE_BRANCH_USER |\ + PERF_SAMPLE_BRANCH_KERNEL |\ + PERF_SAMPLE_BRANCH_HV) + + uint64_t *mode = (uint64_t *)opt->value; + const struct branch_mode *br; + char *s, *os, *p; + int ret = -1; + + *mode = 0; + + /* because str is read-only */ + s = os = strdup(str); + if (!s) + return -1; + + for (;;) { + p = strchr(s, ','); + if (p) + *p = '\0'; + + for (br = branch_modes; br->name; br++) { + if (!strcasecmp(s, br->name)) + break; + } + if (!br->name) + goto error; + + *mode |= br->mode; + + if (!p) + break; + + s = p + 1; + } + ret = 0; + + if ((*mode & ~ONLY_PLM) == 0) { + error("need at least one branch type with -b\n"); + ret = -1; + } +error: + free(os); + return ret; +} + static const char * const record_usage[] = { "perf record [] []", "perf record [] -- []", @@ -727,6 +798,9 @@ const struct option record_options[] = { "monitor event in cgroup name only", parse_cgroups), OPT_STRING('u', "uid", &record.uid_str, "user", "user to profile"), + OPT_CALLBACK('b', "branch-stack", &record.opts.branch_stack, + "branch mode mask", "branch stack sampling modes", + parse_branch_stack), OPT_END() }; diff --git a/tools/perf/perf.h b/tools/perf/perf.h index 358f40135c4d..eec392e48067 100644 --- a/tools/perf/perf.h +++ b/tools/perf/perf.h @@ -222,6 +222,7 @@ struct perf_record_opts { unsigned int freq; unsigned int mmap_pages; unsigned int user_freq; + int branch_stack; u64 default_interval; u64 user_interval; const char *cpu_list; diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c index a1fd1cd2a5af..f421f7cbc0d3 100644 --- a/tools/perf/util/evsel.c +++ b/tools/perf/util/evsel.c @@ -126,6 +126,10 @@ void perf_evsel__config(struct perf_evsel *evsel, struct perf_record_opts *opts) attr->watermark = 0; attr->wakeup_events = 1; } + if (opts->branch_stack) { + attr->sample_type |= PERF_SAMPLE_BRANCH_STACK; + attr->branch_sample_type = opts->branch_stack; + } attr->mmap = track; attr->comm = track; -- 2.20.1