Move code to read macOS resource coalition stats to //components/power_metrics.

This allows reuse by the code that records histograms in Chrome and
the "power_sampler" tool in //tools/mac/power.

Bug: 1254332
Change-Id: I6c0d9fcdee9d556b061868a90344843b4e80d587
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3265524
Commit-Queue: François Doray <fdoray@chromium.org>
Reviewed-by: Jochen Eisinger <jochen@chromium.org>
Reviewed-by: Etienne Pierre-Doray <etiennep@chromium.org>
Cr-Commit-Position: refs/heads/main@{#945055}

components/power_metrics/BUILD.gn

@@ -0,0 +1,15 @@
+# Copyright 2021 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+if (is_mac) {
+  static_library("power_metrics") {
+    sources = [
+      "resource_coalition_internal_types_mac.h",
+      "resource_coalition_mac.h",
+      "resource_coalition_mac.mm",
+    ]
+
+    deps = [ "//base" ]
+  }
+}

components/power_metrics/DIR_METADATA

@@ -0,0 +1,12 @@
+# Metadata information for this directory.
+#
+# For more information on DIR_METADATA files, see:
+#   https://source.chromium.org/chromium/infra/infra/+/main:go/src/infra/tools/dirmd/README.md
+#
+# For the schema of this file, see Metadata message:
+#   https://source.chromium.org/chromium/infra/infra/+/main:go/src/infra/tools/dirmd/proto/dir_metadata.proto
+
+monorail {
+  component: "Internals>Power"
+}
+team_email: "chrome-catan-battery@google.com"

components/power_metrics/OWNERS

@@ -0,0 +1,2 @@
+etiennep@chromium.org
+fdoray@chromium.org

components/power_metrics/resource_coalition_internal_types_mac.h

@@ -0,0 +1,79 @@
+// Copyright 2021 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// This file defines data types used to retrieve coalition metrics from the OS.
+
+#ifndef COMPONENTS_POWER_METRICS_RESOURCE_COALITION_INTERNAL_TYPES_MAC_H_
+#define COMPONENTS_POWER_METRICS_RESOURCE_COALITION_INTERNAL_TYPES_MAC_H_
+
+#include <stdint.h>
+
+// Comes from osfmk/mach/coalition.h
+#define COALITION_TYPE_RESOURCE (0)
+#define COALITION_TYPE_JETSAM (1)
+#define COALITION_TYPE_MAX (1)
+
+#define COALITION_NUM_TYPES (COALITION_TYPE_MAX + 1)
+
+#define COALITION_NUM_THREAD_QOS_TYPES 7
+
+// Comes from osfmk/mach/thread_policy.h
+#define THREAD_QOS_UNSPECIFIED 0
+#define THREAD_QOS_DEFAULT THREAD_QOS_UNSPECIFIED /* Temporary rename */
+#define THREAD_QOS_MAINTENANCE 1
+#define THREAD_QOS_BACKGROUND 2
+#define THREAD_QOS_UTILITY 3
+#define THREAD_QOS_LEGACY 4 /* i.e. default workq threads */
+#define THREAD_QOS_USER_INITIATED 5
+#define THREAD_QOS_USER_INTERACTIVE 6
+
+#define THREAD_QOS_LAST 7
+
+static_assert(COALITION_NUM_THREAD_QOS_TYPES == THREAD_QOS_LAST,
+              "Unexpected number of QoS levels.");
+
+// Comes from bsd/sys/coalition.h
+struct coalition_resource_usage {
+  uint64_t tasks_started;
+  uint64_t tasks_exited;
+  uint64_t time_nonempty;
+  uint64_t cpu_time;
+  uint64_t interrupt_wakeups;
+  uint64_t platform_idle_wakeups;
+  uint64_t bytesread;
+  uint64_t byteswritten;
+  uint64_t gpu_time;
+  uint64_t cpu_time_billed_to_me;
+  uint64_t cpu_time_billed_to_others;
+  uint64_t energy;
+  uint64_t logical_immediate_writes;
+  uint64_t logical_deferred_writes;
+  uint64_t logical_invalidated_writes;
+  uint64_t logical_metadata_writes;
+  uint64_t logical_immediate_writes_to_external;
+  uint64_t logical_deferred_writes_to_external;
+  uint64_t logical_invalidated_writes_to_external;
+  uint64_t logical_metadata_writes_to_external;
+  uint64_t energy_billed_to_me;
+  uint64_t energy_billed_to_others;
+  uint64_t cpu_ptime;
+  uint64_t cpu_time_eqos_len; /* Stores the number of thread QoS types */
+  uint64_t cpu_time_eqos[COALITION_NUM_THREAD_QOS_TYPES];
+  uint64_t cpu_instructions;
+  uint64_t cpu_cycles;
+  uint64_t fs_metadata_writes;
+  uint64_t pm_writes;
+};
+
+struct proc_pidcoalitioninfo {
+  uint64_t coalition_id[COALITION_NUM_TYPES];
+  uint64_t reserved1;
+  uint64_t reserved2;
+  uint64_t reserved3;
+};
+
+// Comes from bsd/sys/proc_info.h
+#define PROC_PIDCOALITIONINFO 20
+
+#endif  // COMPONENTS_POWER_METRICS_RESOURCE_COALITION_INTERNAL_TYPES_MAC_H_

components/power_metrics/resource_coalition_mac.h

@@ -0,0 +1,34 @@
+// Copyright 2021 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Resource Coalition is an (undocumented) mechanism available in macOS that
+// allows retrieving accrued resource usage metrics for a group of processes,
+// including processes that have died. Typically, a coalition includes a root
+// process and its descendants. The source can help understand the mechanism:
+// https://github.com/apple/darwin-xnu/blob/main/osfmk/kern/coalition.c
+
+#ifndef COMPONENTS_POWER_METRICS_RESOURCE_COALITION_MAC_H_
+#define COMPONENTS_POWER_METRICS_RESOURCE_COALITION_MAC_H_
+
+#include <stdint.h>
+#include <memory>
+
+#include "base/process/process_handle.h"
+#include "components/power_metrics/resource_coalition_internal_types_mac.h"
+#include "third_party/abseil-cpp/absl/types/optional.h"
+
+namespace power_metrics {
+
+// Returns the coalition id for the process identified by |pid| or nullopt if
+// not available.
+absl::optional<uint64_t> GetProcessCoalitionId(base::ProcessId pid);
+
+// Returns resource usage data for the coalition identified by |coalition_id|,
+// or nullptr if not available.
+std::unique_ptr<coalition_resource_usage> GetCoalitionResourceUsage(
+    int64_t coalition_id);
+
+}  // namespace power_metrics
+
+#endif  // COMPONENTS_PPOWER_METRICS_RESOURCE_COALITION_MAC_H_

components/power_metrics/resource_coalition_mac.mm

@@ -0,0 +1,39 @@
+// Copyright 2021 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "components/power_metrics/resource_coalition_mac.h"
+
+#include <libproc.h>
+
+#include "base/check_op.h"
+
+extern "C" int coalition_info_resource_usage(
+    uint64_t cid,
+    struct coalition_resource_usage* cru,
+    size_t sz);
+
+namespace power_metrics {
+
+absl::optional<uint64_t> GetProcessCoalitionId(base::ProcessId pid) {
+  proc_pidcoalitioninfo coalition_info = {};
+  int res = proc_pidinfo(pid, PROC_PIDCOALITIONINFO, 0, &coalition_info,
+                         sizeof(coalition_info));
+
+  if (res != sizeof(coalition_info))
+    return absl::nullopt;
+
+  return coalition_info.coalition_id[COALITION_TYPE_RESOURCE];
+}
+
+std::unique_ptr<coalition_resource_usage> GetCoalitionResourceUsage(
+    int64_t coalition_id) {
+  auto cru = std::make_unique<coalition_resource_usage>();
+  uint64_t res = coalition_info_resource_usage(
+      coalition_id, cru.get(), sizeof(coalition_resource_usage));
+  if (res == 0U)
+    return cru;
+  return nullptr;
+}
+
+}  // power_metrics