perf bpf filter: Add logical OR operator
authorNamhyung Kim <namhyung@kernel.org>
Tue, 14 Mar 2023 23:42:35 +0000 (16:42 -0700)
committerArnaldo Carvalho de Melo <acme@redhat.com>
Wed, 15 Mar 2023 14:08:36 +0000 (11:08 -0300)
It supports two or more expressions connected as a group and the group
result is considered true when one of them returns true.  The new group
operators (GROUP_BEGIN and GROUP_END) are added to setup and check the
condition.  As it doesn't allow nested groups, the condition is saved
in local variables.

For example, the following is to get samples only if the data source
memory level is L2 cache or the weight value is greater than 30.

  $ sudo ./perf record -adW -e cpu/mem-loads/pp \
  > --filter 'mem_lvl == l2 || weight > 30' -- sleep 1

  $ sudo ./perf script -F data_src,weight
     10668100842 |OP LOAD|LVL L3 or L3 hit|SNP None|TLB L1 or L2 hit|LCK No|BLK  N/A     47
     11868100242 |OP LOAD|LVL LFB/MAB or LFB/MAB hit|SNP None|TLB L1 or L2 hit|LCK No|BLK  N/A      57
     10668100842 |OP LOAD|LVL L3 or L3 hit|SNP None|TLB L1 or L2 hit|LCK No|BLK  N/A                56
     10650100842 |OP LOAD|LVL L3 or L3 hit|SNP None|TLB L2 miss|LCK No|BLK  N/A                    144
     10468100442 |OP LOAD|LVL L2 or L2 hit|SNP None|TLB L1 or L2 hit|LCK No|BLK  N/A                16
     10468100442 |OP LOAD|LVL L2 or L2 hit|SNP None|TLB L1 or L2 hit|LCK No|BLK  N/A                20
     11868100242 |OP LOAD|LVL LFB/MAB or LFB/MAB hit|SNP None|TLB L1 or L2 hit|LCK No|BLK  N/A     189
     1026a100142 |OP LOAD|LVL L1 or L1 hit|SNP None|TLB L1 or L2 hit|LCK Yes|BLK  N/A              193
     10468100442 |OP LOAD|LVL L2 or L2 hit|SNP None|TLB L1 or L2 hit|LCK No|BLK  N/A                18
     ...

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Hao Luo <haoluo@google.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: James Clark <james.clark@arm.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ravi Bangoria <ravi.bangoria@amd.com>
Cc: Song Liu <song@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: bpf@vger.kernel.org
Link: https://lore.kernel.org/r/20230314234237.3008956-2-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
tools/perf/util/bpf-filter.c
tools/perf/util/bpf-filter.h
tools/perf/util/bpf-filter.l
tools/perf/util/bpf-filter.y
tools/perf/util/bpf_skel/sample-filter.h
tools/perf/util/bpf_skel/sample_filter.bpf.c

index 743c69fd6cd481ec9ed5184c683b65b436c318cb..bd638737e12f6a5acd454d0e9107d851ad260b20 100644 (file)
@@ -42,8 +42,32 @@ int perf_bpf_filter__prepare(struct evsel *evsel)
                };
                bpf_map_update_elem(fd, &i, &entry, BPF_ANY);
                i++;
+
+               if (expr->op == PBF_OP_GROUP_BEGIN) {
+                       struct perf_bpf_filter_expr *group;
+
+                       list_for_each_entry(group, &expr->groups, list) {
+                               struct perf_bpf_filter_entry group_entry = {
+                                       .op = group->op,
+                                       .part = group->part,
+                                       .flags = group->sample_flags,
+                                       .value = group->val,
+                               };
+                               bpf_map_update_elem(fd, &i, &group_entry, BPF_ANY);
+                               i++;
+                       }
+
+                       memset(&entry, 0, sizeof(entry));
+                       entry.op = PBF_OP_GROUP_END;
+                       bpf_map_update_elem(fd, &i, &entry, BPF_ANY);
+                       i++;
+               }
        }
 
+       if (i > MAX_FILTERS) {
+               pr_err("Too many filters: %d (max = %d)\n", i, MAX_FILTERS);
+               return -1;
+       }
        prog = skel->progs.perf_sample_filter;
        for (x = 0; x < xyarray__max_x(evsel->core.fd); x++) {
                for (y = 0; y < xyarray__max_y(evsel->core.fd); y++) {
@@ -89,6 +113,7 @@ struct perf_bpf_filter_expr *perf_bpf_filter_expr__new(unsigned long sample_flag
                expr->part = part;
                expr->op = op;
                expr->val = val;
+               INIT_LIST_HEAD(&expr->groups);
        }
        return expr;
 }
index 3f8827bd965fdb494cdb3aebf077d7a446e56b5c..7afd159411b8b8e74ae56a5f1456c7102ccc98f6 100644 (file)
@@ -8,6 +8,7 @@
 
 struct perf_bpf_filter_expr {
        struct list_head list;
+       struct list_head groups;
        enum perf_bpf_filter_op op;
        int part;
        unsigned long sample_flags;
index 3e66b7a0215e97c47adc0dbf6d96a83a4eb4e4ee..d4ff0f1345cddc738bb6d87269c1ddeb9fa79523 100644 (file)
@@ -151,6 +151,7 @@ hops2               { return constant(PERF_MEM_HOPS_2); }
 hops3          { return constant(PERF_MEM_HOPS_3); }
 
 ","            { return ','; }
+"||"           { return BFT_LOGICAL_OR; }
 
 {ident}                { return error("ident"); }
 .              { return error("input"); }
index 0ca6532afd8dc0dd96015469481d4a52e2785cf1..07d6c7926c13aaf047367e5d15352e373896ba90 100644 (file)
@@ -28,8 +28,8 @@ static void perf_bpf_filter_error(struct list_head *expr __maybe_unused,
        struct perf_bpf_filter_expr *expr;
 }
 
-%token BFT_SAMPLE BFT_OP BFT_ERROR BFT_NUM
-%type <expr> filter_term
+%token BFT_SAMPLE BFT_OP BFT_ERROR BFT_NUM BFT_LOGICAL_OR
+%type <expr> filter_term filter_expr
 %destructor { free ($$); } <expr>
 %type <sample> BFT_SAMPLE
 %type <op> BFT_OP
@@ -49,6 +49,27 @@ filter_term
 }
 
 filter_term:
+filter_term BFT_LOGICAL_OR filter_expr
+{
+       struct perf_bpf_filter_expr *expr;
+
+       if ($1->op == PBF_OP_GROUP_BEGIN) {
+               expr = $1;
+       } else {
+               expr = perf_bpf_filter_expr__new(0, 0, PBF_OP_GROUP_BEGIN, 1);
+               list_add_tail(&$1->list, &expr->groups);
+       }
+       expr->val++;
+       list_add_tail(&$3->list, &expr->groups);
+       $$ = expr;
+}
+|
+filter_expr
+{
+       $$ = $1;
+}
+
+filter_expr:
 BFT_SAMPLE BFT_OP BFT_NUM
 {
        $$ = perf_bpf_filter_expr__new($1.type, $1.part, $2, $3);
index 6b9fd554ad7b91b48e0ca1a2376472004a94e6b9..2e96e1ab084ae9af421467cb14a88eafd4c9d90d 100644 (file)
@@ -1,7 +1,7 @@
 #ifndef PERF_UTIL_BPF_SKEL_SAMPLE_FILTER_H
 #define PERF_UTIL_BPF_SKEL_SAMPLE_FILTER_H
 
-#define MAX_FILTERS  32
+#define MAX_FILTERS  64
 
 /* supported filter operations */
 enum perf_bpf_filter_op {
@@ -11,7 +11,9 @@ enum perf_bpf_filter_op {
        PBF_OP_GE,
        PBF_OP_LT,
        PBF_OP_LE,
-       PBF_OP_AND
+       PBF_OP_AND,
+       PBF_OP_GROUP_BEGIN,
+       PBF_OP_GROUP_END,
 };
 
 /* BPF map entry for filtering */
index 88dbc788d257ab0b2affc3d889a9c2880a9ceaf8..57e3c67d6d37c40612f2a865d0c07dc8688323f3 100644 (file)
@@ -99,6 +99,14 @@ static inline __u64 perf_get_sample(struct bpf_perf_event_data_kern *kctx,
        return 0;
 }
 
+#define CHECK_RESULT(data, op, val)                    \
+       if (!(data op val)) {                           \
+               if (!in_group)                          \
+                       goto drop;                      \
+       } else if (in_group) {                          \
+               group_result = 1;                       \
+       }
+
 /* BPF program to be called from perf event overflow handler */
 SEC("perf_event")
 int perf_sample_filter(void *ctx)
@@ -106,6 +114,8 @@ int perf_sample_filter(void *ctx)
        struct bpf_perf_event_data_kern *kctx;
        struct perf_bpf_filter_entry *entry;
        __u64 sample_data;
+       int in_group = 0;
+       int group_result = 0;
        int i;
 
        kctx = bpf_cast_to_kern_ctx(ctx);
@@ -120,32 +130,34 @@ int perf_sample_filter(void *ctx)
 
                switch (entry->op) {
                case PBF_OP_EQ:
-                       if (!(sample_data == entry->value))
-                               goto drop;
+                       CHECK_RESULT(sample_data, ==, entry->value)
                        break;
                case PBF_OP_NEQ:
-                       if (!(sample_data != entry->value))
-                               goto drop;
+                       CHECK_RESULT(sample_data, !=, entry->value)
                        break;
                case PBF_OP_GT:
-                       if (!(sample_data > entry->value))
-                               goto drop;
+                       CHECK_RESULT(sample_data, >, entry->value)
                        break;
                case PBF_OP_GE:
-                       if (!(sample_data >= entry->value))
-                               goto drop;
+                       CHECK_RESULT(sample_data, >=, entry->value)
                        break;
                case PBF_OP_LT:
-                       if (!(sample_data < entry->value))
-                               goto drop;
+                       CHECK_RESULT(sample_data, <, entry->value)
                        break;
                case PBF_OP_LE:
-                       if (!(sample_data <= entry->value))
-                               goto drop;
+                       CHECK_RESULT(sample_data, <=, entry->value)
                        break;
                case PBF_OP_AND:
-                       if (!(sample_data & entry->value))
+                       CHECK_RESULT(sample_data, &, entry->value)
+                       break;
+               case PBF_OP_GROUP_BEGIN:
+                       in_group = 1;
+                       group_result = 0;
+                       break;
+               case PBF_OP_GROUP_END:
+                       if (group_result == 0)
                                goto drop;
+                       in_group = 0;
                        break;
                }
        }