Move pprof into shared sub-tree. (#1290)

Summary: We meed to move this code into a location that can be shared
between `stirling` and `carnot`.

Type of change: /kind cleanup

Test Plan: The pprof export code will be integrated into a future diff.
We have tested it locally using the `stirling_profiler` binary. Its test
case will live inside of the (future work) `carnot` UDA that generates a
profiling pprof protobuf for export.

Signed-off-by: Pete Stevenson <jps@pixielabs.ai>

Author: Pete Stevenson

…nnectors/perf_profiler/pprof/BUILD.bazel src/shared/pprof/BUILD.bazelsrc/stirling/source_connectors/perf_profiler/pprof/BUILD.bazel renamed to src/shared/pprof/BUILD.bazel src/stirling/source_connectors/perf_profiler/pprof/BUILD.bazel renamed to src/shared/pprof/BUILD.bazel

@@ -17,7 +17,7 @@
 load("@rules_cc//cc:defs.bzl", "cc_proto_library")
 load("//bazel:pl_build_system.bzl", "pl_cc_library")
 
-package(default_visibility = ["//src/stirling:__subpackages__"])
+package(default_visibility = ["//src:__subpackages__"])
 
 cc_proto_library(
     name = "pprof_proto_cc",

…_connectors/perf_profiler/pprof/pprof.cc src/shared/pprof/pprof.ccsrc/stirling/source_connectors/perf_profiler/pprof/pprof.cc renamed to src/shared/pprof/pprof.cc src/stirling/source_connectors/perf_profiler/pprof/pprof.cc renamed to src/shared/pprof/pprof.cc

@@ -16,24 +16,21 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
-#include "src/stirling/source_connectors/perf_profiler/pprof/pprof.h"
-
-#include <gflags/gflags.h>
+#include "src/shared/pprof/pprof.h"
 
 #include <absl/strings/str_split.h>
 #include <vector>
 
-DECLARE_uint32(stirling_profiler_stack_trace_sample_period_ms);
-
 namespace px {
-namespace stirling {
+namespace shared {
 
-PProfProfile CreatePProfProfile(const uint32_t num_cpus, const histo_t& histo) {
+PProfProfile CreatePProfProfile(const uint32_t num_cpus, const uint32_t period_ms,
+                                const absl::flat_hash_map<std::string, uint64_t>& histo) {
   // Info on the pprof proto format:
   // https://github.com/google/pprof/blob/main/proto/profile.proto
 
+  // period_ms is the stack trace sampling period used by the eBPF stack trace sampling probe.
   // period_ns will be used when populating the nanos count.
-  const uint64_t period_ms = FLAGS_stirling_profiler_stack_trace_sample_period_ms;
   const uint64_t period_ns = period_ms * 1000 * 1000;
 
   // Tracks which strings have been inserted into the profile.
@@ -138,5 +135,5 @@ PProfProfile CreatePProfProfile(const uint32_t num_cpus, const histo_t& histo) {
   return profile;
 }
 
-}  // namespace stirling
+}  // namespace shared
 }  // namespace px

…e_connectors/perf_profiler/pprof/pprof.h src/shared/pprof/pprof.hsrc/stirling/source_connectors/perf_profiler/pprof/pprof.h renamed to src/shared/pprof/pprof.h src/stirling/source_connectors/perf_profiler/pprof/pprof.h renamed to src/shared/pprof/pprof.h

@@ -25,13 +25,13 @@
 #include "proto/profile.pb.h"
 
 namespace px {
-namespace stirling {
+namespace shared {
 
 using PProfProfile = ::perftools::profiles::Profile;
-using histo_t = absl::flat_hash_map<std::string, uint64_t>;
 
 // https://github.com/google/pprof/blob/main/proto/profile.proto
-PProfProfile CreatePProfProfile(const uint32_t num_cpus, const histo_t& histo);
+PProfProfile CreatePProfProfile(const uint32_t num_cpus, const uint32_t period_ms,
+                                const absl::flat_hash_map<std::string, uint64_t>& histo);
 
-}  // namespace stirling
+}  // namespace shared
 }  // namespace px