Add Perf Event tests

tests/cc/CMakeLists.txt

@@ -16,6 +16,7 @@ add_executable(test_libbcc
 	test_array_table.cc
 	test_bpf_table.cc
 	test_hash_table.cc
+	test_perf_event.cc
 	test_usdt_args.cc
 	test_usdt_probes.cc
 	utils.cc)

tests/cc/test_bpf_table.cc

@@ -128,6 +128,8 @@ TEST_CASE("test bpf stack table", "[bpf_stack_table]") {
       int zero = 0, *val;
       val = id.lookup_or_init(&zero, &stack_id);
       (*val) = stack_id;
+
+      return 0;
     }
   )";
 

tests/cc/test_perf_event.cc

+/*
+ * Copyright (c) 2017 Facebook, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <linux/perf_event.h>
+#include <linux/version.h>
+#include <unistd.h>
+#include <string>
+
+#include "BPF.h"
+#include "catch.hpp"
+
+TEST_CASE("test read perf event", "[bpf_perf_event]") {
+// The basic bpf_perf_event_read is supported since Kernel 4.3. However in that
+// version it only supported HARDWARE and RAW events. On the other hand, our
+// tests running on Jenkins won't have availiable HARDWARE counters since they
+// are running on VMs. The support of other types of events such as SOFTWARE are
+// only added since Kernel 4.13, hence we can only run the test since that.
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 13, 0)
+  const std::string BPF_PROGRAM = R"(
+    BPF_PERF_ARRAY(cnt, NUM_CPUS);
+    BPF_HASH(val, int, u64, 1);
+    BPF_HASH(ret, int, int, 1);
+    BPF_HASH(counter, int, struct bpf_perf_event_value, 1);
+
+    int on_sys_getuid(void *ctx) {
+      int zero = 0;
+
+      u64 v = cnt.perf_read(CUR_CPU_IDENTIFIER);
+      if (((s64)v < 0) && ((s64)v > -256))
+        return 0;
+      val.update(&zero, &v);
+    #if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 15, 0)
+      u32 cpu = bpf_get_smp_processor_id();
+      struct bpf_perf_event_value c = {0};
+      int r = cnt.perf_counter_value(cpu, &c, sizeof(c));
+      ret.update(&zero, &r);
+      counter.update(&zero, &c);
+    #endif
+      return 0;
+    }
+  )";
+
+  ebpf::BPF bpf;
+  ebpf::StatusTuple res(0);
+  res = bpf.init(
+      BPF_PROGRAM,
+      {"-DNUM_CPUS=" + std::to_string(sysconf(_SC_NPROCESSORS_ONLN))}, {});
+  REQUIRE(res.code() == 0);
+  res =
+      bpf.open_perf_event("cnt", PERF_TYPE_SOFTWARE, PERF_COUNT_SW_CPU_CLOCK);
+  REQUIRE(res.code() == 0);
+  res = bpf.attach_kprobe("sys_getuid", "on_sys_getuid");
+  REQUIRE(res.code() == 0);
+  REQUIRE(getuid() >= 0);
+  res = bpf.detach_kprobe("sys_getuid");
+  REQUIRE(res.code() == 0);
+  res = bpf.close_perf_event("cnt");
+  REQUIRE(res.code() == 0);
+
+  auto val = bpf.get_hash_table<int, uint64_t>("val");
+  REQUIRE(val[0] >= 0);
+#endif
+
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 15, 0)
+  auto counter_table =
+      bpf.get_hash_table<int, struct bpf_perf_event_value>("counter");
+  auto counter = counter_table[0];
+  auto ret = bpf.get_hash_table<int, int>("ret");
+  REQUIRE(ret[0] == 0);
+  REQUIRE(counter.counter >= 0);
+  REQUIRE(counter.enabled > 0);
+  REQUIRE(counter.running >= 0);
+  REQUIRE(counter.running <= counter.enabled);
+#endif
+}
+
+TEST_CASE("test attach perf event", "[bpf_perf_event]") {
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 9, 0)
+  const std::string BPF_PROGRAM = R"(
+    BPF_HASH(pid, int, u64, 1);
+    BPF_HASH(ret, int, int, 1);
+    BPF_HASH(counter, int, struct bpf_perf_event_value, 1);
+
+    int on_event(void *ctx) {
+      int zero = 0;
+      
+      u64 p = bpf_get_current_pid_tgid();
+      pid.update(&zero, &p);
+    #if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 15, 0)
+      struct bpf_perf_event_value c = {0};
+      int r = bpf_perf_prog_read_value(ctx, &c, sizeof(c));
+      ret.update(&zero, &r);
+      counter.update(&zero, &c);
+    #endif
+      return 0;
+    }
+  )";
+
+  ebpf::BPF bpf;
+  ebpf::StatusTuple res(0);
+  res = bpf.init(BPF_PROGRAM);
+  REQUIRE(res.code() == 0);
+  res = bpf.attach_perf_event(PERF_TYPE_SOFTWARE, PERF_COUNT_SW_CPU_CLOCK,
+                              "on_event", 0, 1000);
+  REQUIRE(res.code() == 0);
+  sleep(1);
+  res = bpf.detach_perf_event(PERF_TYPE_SOFTWARE, PERF_COUNT_SW_CPU_CLOCK);
+  REQUIRE(res.code() == 0);
+
+  auto pid = bpf.get_hash_table<int, uint64_t>("pid");
+  REQUIRE(pid[0] >= 0);
+#endif
+
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 15, 0)
+  auto counter_table =
+      bpf.get_hash_table<int, struct bpf_perf_event_value>("counter");
+  auto counter = counter_table[0];
+  auto ret = bpf.get_hash_table<int, int>("ret");
+  REQUIRE(ret[0] == 0);
+  REQUIRE(counter.counter >= 0);
+  REQUIRE(counter.enabled >= 1000000000);
+  REQUIRE(counter.running >= 0);
+  REQUIRE(counter.running <= counter.enabled);
+#endif
+}