[PATCH v4 09/16] perf tools: Enable indices setting syntax for BPF maps

Wang Nan
2015-12-08T02:27:19Z

This patch introduce a new syntax to perf event parser:

# perf record -e bpf_file.c/maps.mymap.value[0,3...5,7]=1234/ ...

By utilizing the basic facilities in bpf-loader.c which allow setting
different slots in a BPF map separately, the newly introduced syntax
allows perf to control specific elements in a BPF map.

Test result:

# cat ./test_bpf_map_3.c
/************************ BEGIN **************************/
#define SEC(NAME) __attribute__((section(NAME), used))
enum bpf_map_type {
BPF_MAP_TYPE_ARRAY = 2,
};
struct bpf_map_def {
unsigned int type;
unsigned int key_size;
unsigned int value_size;
unsigned int max_entries;
};
static void *(*map_lookup_elem)(struct bpf_map_def *, void *) =
(void *)1;
static int (*bpf_trace_printk)(const char *fmt, int fmt_size, ...) =
(void *)6;
struct bpf_map_def SEC("maps") channel = {
.type = BPF_MAP_TYPE_ARRAY,
.key_size = sizeof(int),
.value_size = sizeof(unsigned char),
.max_entries = 100,
};
SEC("func=hrtimer_nanosleep rqtp->tv_nsec")
int func(void *ctx, int err, long nsec)
{
char fmt[] = "%ld\n";
long usec = nsec * 0x10624dd3 >> 38; // nsec / 1000
int key = (int)usec;
unsigned char *pval = map_lookup_elem(&channel, &key);

if (!pval)
return 0;
bpf_trace_printk(fmt, sizeof(fmt), (unsigned char)*pval);
return 0;
}
char _license[] SEC("license") = "GPL";
int _version SEC("version") = LINUX_VERSION_CODE;
/************************* END ***************************/

Normal case:
# echo "" > /sys/kernel/debug/tracing/trace
# ./perf record -e './test_bpf_map_3.c/maps:channel.value[0,1,2,3...5]=101/' usleep 2
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.012 MB perf.data ]
# cat /sys/kernel/debug/tracing/trace | grep usleep
usleep-405 [004] d... 2745423.547822: : 101
# ./perf record -e './test_bpf_map_3.c/maps:channel.value[0...9,20...29]=102,maps:channel.value[10...19]=103/' usleep 3
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.012 MB perf.data ]
# ./perf record -e './test_bpf_map_3.c/maps:channel.value[0...9,20...29]=102,maps:channel.value[10...19]=103/' usleep 15
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.012 MB perf.data ]
# cat /sys/kernel/debug/tracing/trace | grep usleep
usleep-405 [004] d... 2745423.547822: : 101
usleep-655 [006] d... 2745434.122814: : 102
usleep-904 [006] d... 2745439.916264: : 103
# ./perf record -e './test_bpf_map_3.c/maps:channel.value[all]=104/' usleep 99
# cat /sys/kernel/debug/tracing/trace | grep usleep
usleep-405 [004] d... 2745423.547822: : 101
usleep-655 [006] d... 2745434.122814: : 102
usleep-904 [006] d... 2745439.916264: : 103
usleep-1537 [003] d... 2745538.053737: : 104

Error case:
# ./perf record -e './test_bpf_map_3.c/maps:channel.value[10...1000]=104/' usleep 99
event syntax error: '..annel.value[10...1000]=104/'
\___ Index too large
Hint: Valid config terms:
maps:[<arraymap>].value<indices>=[value]
maps:[<eventmap>].event<indices>=[event]

where <indices> is something like [0,3...5] or [all]
(add -v to see detail)
Run 'perf list' for a list of valid events

Usage: perf record [<options>] [<command>]
or: perf record [<options>] -- <command> [<options>]

-e, --event <event> event selector. use 'perf list' to list available events

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
---
tools/perf/util/parse-events.c | 5 ++-
tools/perf/util/parse-events.l | 13 ++++++-
tools/perf/util/parse-events.y | 85 ++++++++++++++++++++++++++++++++++++++++++
3 files changed, 100 insertions(+), 3 deletions(-)

diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
index af3d657..abdf551 100644
--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -660,9 +660,10 @@ parse_events_config_bpf(struct parse_events_evlist *data,
sizeof(errbuf));
data->error->help = strdup(
"Hint:\tValid config terms:\n"
-" \tmaps:[<arraymap>].value=[value]\n"
-" \tmaps:[<eventmap>].event=[event]\n"
+" \tmaps:[<arraymap>].value<indices>=[value]\n"
+" \tmaps:[<eventmap>].event<indices>=[event]\n"
"\n"
+" \twhere <indices> is something like [0,3...5] or [all]\n"
" \t(add -v to see detail)");
data->error->str = strdup(errbuf);
if (err == -BPF_LOADER_ERRNO__OBJCONF_MAP_VALUE)
diff --git a/tools/perf/util/parse-events.l b/tools/perf/util/parse-events.l
index 4387728..8bb3437 100644
--- a/tools/perf/util/parse-events.l
+++ b/tools/perf/util/parse-events.l
@@ -9,8 +9,8 @@
%{
#include <errno.h>
#include "../perf.h"
-#include "parse-events-bison.h"
#include "parse-events.h"
+#include "parse-events-bison.h"

char *parse_events_get_text(yyscan_t yyscanner);
YYSTYPE *parse_events_get_lval(yyscan_t yyscanner);
@@ -111,6 +111,7 @@ do { \
%x mem
%s config
%x event
+%x array

group [^,{}/]*[{][^}]*[}][^,{}/]*
event_pmu [^,{}/]+[/][^/]*[/][^,{}/]*
@@ -176,6 +177,14 @@ modifier_bp [rwx]{1,3}

}

+<array>{
+"]" { BEGIN(config); return ']'; }
+{num_dec} { return value(yyscanner, 10); }
+{num_hex} { return value(yyscanner, 16); }
+, { return ','; }
+"\.\.\." { return PE_ARRAY_RANGE; }
+}
+
<config>{
/*
* Please update parse_events_formats_error_string any time
@@ -196,6 +205,8 @@ no-inherit { return term(yyscanner, PARSE_EVENTS__TERM_TYPE_NOINHERIT); }
, { return ','; }
"/" { BEGIN(INITIAL); return '/'; }
{name_minus} { return str(yyscanner, PE_NAME); }
+\[all\] { return PE_ARRAY_ALL; }
+"[" { BEGIN(array); return '['; }
}

<mem>{
diff --git a/tools/perf/util/parse-events.y b/tools/perf/util/parse-events.y
index c3cbd7a..7e93b9f 100644
--- a/tools/perf/util/parse-events.y
+++ b/tools/perf/util/parse-events.y
@@ -48,6 +48,7 @@ static inc_group_count(struct list_head *list,
%token PE_PREFIX_MEM PE_PREFIX_RAW PE_PREFIX_GROUP
%token PE_ERROR
%token PE_PMU_EVENT_PRE PE_PMU_EVENT_SUF PE_KERNEL_PMU_EVENT
+%token PE_ARRAY_ALL PE_ARRAY_RANGE
%type <num> PE_VALUE
%type <num> PE_VALUE_SYM_HW
%type <num> PE_VALUE_SYM_SW
@@ -84,6 +85,9 @@ static inc_group_count(struct list_head *list,
%type group_def
%type group
%type groups
+%type <array> array
+%type <array> array_term
+%type <array> array_terms

%union
{
@@ -95,6 +99,7 @@ static inc_group_count(struct list_head *list,
char *sys;
char *event;
} tracepoint_name;
+ struct parse_events_array array;
}
%%

@@ -601,6 +606,86 @@ PE_TERM
ABORT_ON(parse_events_term__num(&term, (int)$1, NULL, 1, &@1, NULL));
$$ = term;
}
+|
+PE_NAME array '=' PE_NAME
+{
+ struct parse_events_term *term;
+ int i;
+
+ ABORT_ON(parse_events_term__str(&term, PARSE_EVENTS__TERM_TYPE_USER,
+ $1, $4, &@1, &@4));
+
+ term->array = $2;
+ $$ = term;
+}
+|
+PE_NAME array '=' PE_VALUE
+{
+ struct parse_events_term *term;
+
+ ABORT_ON(parse_events_term__num(&term, PARSE_EVENTS__TERM_TYPE_USER,
+ $1, $4, &@1, &@4));
+ term->array = $2;
+ $$ = term;
+}
+
+array:
+'[' array_terms ']'
+{
+ $$ = $2;
+}
+|
+PE_ARRAY_ALL
+{
+ $$.nr_ranges = 0;
+ $$.ranges = NULL;
+}
+
+array_terms:
+array_terms ',' array_term
+{
+ struct parse_events_array new_array;
+
+ new_array.nr_ranges = $1.nr_ranges + $3.nr_ranges;
+ new_array.ranges = malloc(sizeof(new_array.ranges[0]) *
+ new_array.nr_ranges);
+ ABORT_ON(!new_array.ranges);
+ memcpy(&new_array.ranges[0], $1.ranges,
+ $1.nr_ranges * sizeof(new_array.ranges[0]));
+ memcpy(&new_array.ranges[$1.nr_ranges], $3.ranges,
+ $3.nr_ranges * sizeof(new_array.ranges[0]));
+ free($1.ranges);
+ free($3.ranges);
+ $$ = new_array;
+}
+|
+array_term
+
+array_term:
+PE_VALUE
+{
+ struct parse_events_array array;
+
+ array.nr_ranges = 1;
+ array.ranges = malloc(sizeof(array.ranges[0]));
+ ABORT_ON(!array.ranges);
+ array.ranges[0].start = $1;
+ array.ranges[0].length = 1;
+ $$ = array;
+}
+|
+PE_VALUE PE_ARRAY_RANGE PE_VALUE
+{
+ struct parse_events_array array;
+
+ ABORT_ON($3 < $1);
+ array.nr_ranges = 1;
+ array.ranges = malloc(sizeof(array.ranges[0]));
+ ABORT_ON(!array.ranges);
+ array.ranges[0].start = $1;
+ array.ranges[0].length = $3 - $1 + 1;
+ $$ = array;
+}

sep_dc: ':' |

--
1.8.3.4