[tools/perf] Add webview_cpu_usage metric

This change adds a metric that calculates the amount of time WebView
spends on different frequencies.

Bug: b/157855323
Change-Id: Ibb1fa61cc2ba1479f2b76ef642dc03c64a9a14b5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2231452Reviewed-by: Mikhail Khokhlov <khokhlov@google.com>
Commit-Queue: Oksana Zhuravlova <oksamyt@chromium.org>
Cr-Commit-Position: refs/heads/master@{#775713}

tools/perf/core/tbmv3/metrics/webview_cpu_usage_metric.proto

+syntax = "proto2";
+
+package perfetto.protos;
+
+import "protos/perfetto/metrics/metrics.proto";
+import "protos/perfetto/metrics/custom_options.proto";
+
+message WebViewCPUUsageMetric {
+  optional int64 cpu_time_nanos_below_1ghz = 1;
+  optional int64 cpu_time_nanos_above_1ghz = 2;
+};
+
+extend TraceMetrics {
+  optional WebViewCPUUsageMetric webview_cpu_usage_metric = 458;
+}

tools/perf/core/tbmv3/metrics/webview_cpu_usage_metric.sql

+-- WebView is embedded in the hosting app's main process, which means it shares some threads
+-- with the host app's work. In the future, we will approximate WebView-related power usage
+-- by selecting user slices that belong to WebView and estimating their power use
+-- through the CPU time they consume at different core frequencies.
+-- The initial version of this metric calculates the total time (in nanoseconds)
+-- WebView slices spend in different frequency ranges.
+
+SELECT RUN_METRIC('android/android_cpu.sql');
+
+DROP VIEW IF EXISTS webview_slice;
+
+CREATE VIEW webview_slice AS
+  SELECT *
+  FROM
+    -- TODO(b/156788923): add better conditions.
+    slice WHERE category = 'android_webview';
+
+DROP VIEW IF EXISTS top_level_webview_slice;
+
+-- Since we filter out some slices in webview_slice above, we cannot use the "depth" column
+-- to select only the top-level webview slices. Instead, we have to join webview_slice with itself,
+-- selecting only those events that do not have any children in webview_slice.
+CREATE VIEW top_level_webview_slice AS
+  SELECT *
+  FROM
+    webview_slice s1 WHERE
+  (SELECT COUNT(1)
+  FROM (
+    SELECT *
+    FROM
+      webview_slice s2
+    WHERE s1.track_id = s2.track_id
+    AND s2.ts < s1.ts
+    AND s2.ts + s2.dur > s1.ts + s1.dur
+    LIMIT 1)
+   ) == 0;
+
+DROP VIEW IF EXISTS slices_threads;
+
+CREATE VIEW slices_threads AS
+  SELECT
+    top_level_webview_slice.ts,
+    top_level_webview_slice.dur,
+    thread_track.utid
+FROM top_level_webview_slice INNER JOIN thread_track
+  ON top_level_webview_slice.track_id = thread_track.id;
+
+DROP TABLE IF EXISTS slices_freq;
+
+CREATE VIRTUAL TABLE slices_freq
+  USING SPAN_JOIN (cpu_freq_sched_per_thread PARTITIONED utid,
+                   slices_threads PARTITIONED utid);
+
+-- Get frequencies by utid and cpu.
+SELECT RUN_METRIC('android/android_cpu_raw_metrics_per_core.sql',
+  'input_table', 'slices_freq',
+  'output_table', 'webview_raw_metrics_per_core');
+
+-- TODO(b/155980166): use another query to estimate power consumption based on frequencies.
+
+CREATE VIEW webview_cpu_usage_metric_output AS
+SELECT WebViewCPUUsageMetric(
+    'cpu_time_nanos_below_1ghz',
+    (SELECT IFNULL(CAST(SUM(runtime_ns) AS INT), 0)
+    FROM
+      webview_raw_metrics_per_core
+    WHERE avg_freq_khz < 1000000),
+    'cpu_time_nanos_above_1ghz',
+    (SELECT IFNULL(CAST(SUM(runtime_ns) AS INT), 0)
+    FROM
+      webview_raw_metrics_per_core
+    WHERE avg_freq_khz >= 1000000)
+);