Re: [PATCH v5 4/4] perf tools: Support "branch-misses:pp" on arm64

Mark Rutland
2020-02-28T16:03:38Z

Hi James,

Sorry, I missed this v5 when replying to v4 just now, but my comments
there equally apply here: I don't think that we should be silently
overriding the event requested by the user, and I think that we can make
that request explicit without being too painful for the user.

Thanks,
Mark.

On Tue, Feb 25, 2020 at 11:57:39AM +0000, James Clark wrote:
> From: Tan Xiaojun <tanxiaojun@huawei.com>
>
> At the suggestion of James Clark, use spe to support the precise
> ip of some events. Currently its support event is:
> branch-misses.
>
> Example usage:
>
> $ ./perf record -e branch-misses:pp dd if=/dev/zero of=/dev/null count=10000
> (:p/pp/ppp is same for this case.)
>
> $ ./perf report --stdio
> ("--stdio is not necessary")
>
> --------------------------------------------------------------------
> ...
> # Samples: 14 of event 'branch-misses:pp'
> # Event count (approx.): 14
> #
> # Children Self Command Shared Object Symbol
> # ........ ........ ....... ................. ..........................
> #
> 14.29% 14.29% dd [kernel.kallsyms] [k] __arch_copy_from_user
> 14.29% 14.29% dd libc-2.28.so [.] _dl_addr
> 7.14% 7.14% dd [kernel.kallsyms] [k] __free_pages
> 7.14% 7.14% dd [kernel.kallsyms] [k] __pi_memcpy
> 7.14% 7.14% dd [kernel.kallsyms] [k] pagecache_get_page
> 7.14% 7.14% dd [kernel.kallsyms] [k] unmap_single_vma
> 7.14% 7.14% dd dd [.] 0x00000000000025ec
> 7.14% 7.14% dd ld-2.28.so [.] _dl_lookup_symbol_x
> 7.14% 7.14% dd ld-2.28.so [.] check_match
> 7.14% 7.14% dd libc-2.28.so [.] __mpn_rshift
> 7.14% 7.14% dd libc-2.28.so [.] _nl_intern_locale_data
> 7.14% 7.14% dd libc-2.28.so [.] read_alias_file
> ...
> --------------------------------------------------------------------
>
> Signed-off-by: Tan Xiaojun <tanxiaojun@huawei.com>
> Suggested-by: James Clark <James.Clark@arm.com>
> Tested-by: Qi Liu <liuqi115@hisilicon.com>
> Signed-off-by: James Clark <james.clark@arm.com>
> Cc: Will Deacon <will@kernel.org>
> Cc: Mark Rutland <mark.rutland@arm.com>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Ingo Molnar <mingo@redhat.com>
> Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
> Cc: Jiri Olsa <jolsa@redhat.com>
> Cc: Tan Xiaojun <tanxiaojun@huawei.com>
> Cc: Al Grant <al.grant@arm.com>
> Cc: Namhyung Kim <namhyung@kernel.org>
> ---
> tools/perf/arch/arm/util/auxtrace.c | 39 +++++++++++++++++++++++++++++
> tools/perf/builtin-record.c | 5 ++++
> tools/perf/util/arm-spe.c | 9 +++++++
> tools/perf/util/arm-spe.h | 3 +++
> tools/perf/util/auxtrace.h | 6 +++++
> 5 files changed, 62 insertions(+)
>
> diff --git a/tools/perf/arch/arm/util/auxtrace.c b/tools/perf/arch/arm/util/auxtrace.c
> index 0a6e75b8777a..7f412b7894ab 100644
> --- a/tools/perf/arch/arm/util/auxtrace.c
> +++ b/tools/perf/arch/arm/util/auxtrace.c
> @@ -10,11 +10,25 @@
>
> #include "../../util/auxtrace.h"
> #include "../../util/debug.h"
> +#include "../../util/env.h"
> #include "../../util/evlist.h"
> #include "../../util/pmu.h"
> #include "cs-etm.h"
> #include "arm-spe.h"
>
> +#define SPE_ATTR_TS_ENABLE BIT(0)
> +#define SPE_ATTR_PA_ENABLE BIT(1)
> +#define SPE_ATTR_PCT_ENABLE BIT(2)
> +#define SPE_ATTR_JITTER BIT(16)
> +#define SPE_ATTR_BRANCH_FILTER BIT(32)
> +#define SPE_ATTR_LOAD_FILTER BIT(33)
> +#define SPE_ATTR_STORE_FILTER BIT(34)
> +
> +#define SPE_ATTR_EV_RETIRED BIT(1)
> +#define SPE_ATTR_EV_CACHE BIT(3)
> +#define SPE_ATTR_EV_TLB BIT(5)
> +#define SPE_ATTR_EV_BRANCH BIT(7)
> +
> static struct perf_pmu **find_all_arm_spe_pmus(int *nr_spes, int *err)
> {
> struct perf_pmu **arm_spe_pmus = NULL;
> @@ -108,3 +122,28 @@ struct auxtrace_record
> *err = 0;
> return NULL;
> }
> +
> +void auxtrace__preprocess_evlist(struct evlist *evlist)
> +{
> + struct evsel *evsel;
> + struct perf_pmu *pmu;
> +
> + evlist__for_each_entry(evlist, evsel) {
> + /* Currently only supports precise_ip for branch-misses on arm64 */
> + if (!strcmp(perf_env__arch(evlist->env), "arm64")
> + && evsel->core.attr.config == PERF_COUNT_HW_BRANCH_MISSES
> + && evsel->core.attr.type == PERF_TYPE_HARDWARE
> + && evsel->core.attr.precise_ip)
> + {
> + pmu = perf_pmu__find("arm_spe_0");
> + if (pmu) {
> + evsel->pmu_name = pmu->name;
> + evsel->core.attr.type = pmu->type;
> + evsel->core.attr.config = SPE_ATTR_TS_ENABLE
> + | SPE_ATTR_BRANCH_FILTER;
> + evsel->core.attr.config1 = SPE_ATTR_EV_BRANCH;
> + evsel->core.attr.precise_ip = 0;
> + }
> + }
> + }
> +}
> \ No newline at end of file
> diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
> index 4c301466101b..3bc61f03d572 100644
> --- a/tools/perf/builtin-record.c
> +++ b/tools/perf/builtin-record.c
> @@ -2451,6 +2451,11 @@ int cmd_record(int argc, const char **argv)
>
> argc = parse_options(argc, argv, record_options, record_usage,
> PARSE_OPT_STOP_AT_NON_OPTION);
> +
> + if (auxtrace__preprocess_evlist) {
> + auxtrace__preprocess_evlist(rec->evlist);
> + }
> +
> if (quiet)
> perf_quiet_option();
>
> diff --git a/tools/perf/util/arm-spe.c b/tools/perf/util/arm-spe.c
> index 4ef22a0775a9..b21806c97dd8 100644
> --- a/tools/perf/util/arm-spe.c
> +++ b/tools/perf/util/arm-spe.c
> @@ -778,6 +778,15 @@ arm_spe_synth_events(struct arm_spe *spe, struct perf_session *session)
> attr.sample_id_all = evsel->core.attr.sample_id_all;
> attr.read_format = evsel->core.attr.read_format;
>
> + /* If it is in the precise ip mode, there is no need to
> + * synthesize new events. */
> + if (!strncmp(evsel->name, "branch-misses", 13)) {
> + spe->sample_branch_miss = true;
> + spe->branch_miss_id = evsel->core.id[0];
> +
> + return 0;
> + }
> +
> /* create new id val to be a fixed offset from evsel id */
> id = evsel->core.id[0] + 1000000000;
>
> diff --git a/tools/perf/util/arm-spe.h b/tools/perf/util/arm-spe.h
> index 98d3235781c3..8b1fb191d03a 100644
> --- a/tools/perf/util/arm-spe.h
> +++ b/tools/perf/util/arm-spe.h
> @@ -20,6 +20,8 @@ enum {
> union perf_event;
> struct perf_session;
> struct perf_pmu;
> +struct evlist;
> +struct evsel;
>
> struct auxtrace_record *arm_spe_recording_init(int *err,
> struct perf_pmu *arm_spe_pmu);
> @@ -28,4 +30,5 @@ int arm_spe_process_auxtrace_info(union perf_event *event,
> struct perf_session *session);
>
> struct perf_event_attr *arm_spe_pmu_default_config(struct perf_pmu *arm_spe_pmu);
> +void arm_spe_precise_ip_support(struct evlist *evlist, struct evsel *evsel);
> #endif
> diff --git a/tools/perf/util/auxtrace.h b/tools/perf/util/auxtrace.h
> index 52e148eea7f8..4be56bca54dc 100644
> --- a/tools/perf/util/auxtrace.h
> +++ b/tools/perf/util/auxtrace.h
> @@ -584,6 +584,7 @@ void auxtrace__dump_auxtrace_sample(struct perf_session *session,
> int auxtrace__flush_events(struct perf_session *session, struct perf_tool *tool);
> void auxtrace__free_events(struct perf_session *session);
> void auxtrace__free(struct perf_session *session);
> +void auxtrace__preprocess_evlist(struct evlist *evlist) __attribute__((weak));
>
> #define ITRACE_HELP \
> " i: synthesize instructions events\n" \
> @@ -731,6 +732,11 @@ void auxtrace__free(struct perf_session *session __maybe_unused)
> {
> }
>
> +static inline
> +void auxtrace__preprocess_evlist(struct evlist *evlist __maybe_unused)
> +{
> +}
> +
> static inline
> int auxtrace_index__write(int fd __maybe_unused,
> struct list_head *head __maybe_unused)
> --
> 2.17.1
>