1 files changed, 271 insertions, 0 deletions
diff --git a/libs/androidfw/ResourceTimer.cpp b/libs/androidfw/ResourceTimer.cpp
new file mode 100644
index 000000000000..44128d9e4e3d
--- /dev/null
+++ b/libs/androidfw/ResourceTimer.cpp
@@ -0,0 +1,271 @@
+/*
+ * Copyright (C) 2022 The Android Open Source Project
+ *
+ * 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 <unistd.h>
+#include <string.h>
+
+#include <map>
+#include <atomic>
+
+#include <utils/Log.h>
+#include <androidfw/ResourceTimer.h>
+
+// The following block allows compilation on windows, which does not have getuid().
+#ifdef _WIN32
+#ifdef ERROR
+#undef ERROR
+#endif
+#define getuid() (getUidWindows_)
+#endif
+
+namespace android {
+
+namespace {
+
+#ifdef _WIN32
+// A temporary to confuse lint into thinking that getuid() on windows might return something other
+// than zero.
+int getUidWindows_ = 0;
+#endif
+
+// The number of nanoseconds in a microsecond.
+static const unsigned int US = 1000;
+// The number of nanoseconds in a second.
+static const unsigned int S = 1000 * 1000 * 1000;
+
+// Return the difference between two timespec values.  The difference is in nanoseconds.  If the
+// return value would exceed 2s (2^31 nanoseconds) then UINT_MAX is returned.
+unsigned int diffInNs(timespec const &a, timespec const &b) {
+  timespec r = { 0, 0 };
+  r.tv_nsec = a.tv_nsec - b.tv_nsec;
+  if (r.tv_nsec < 0) {
+    r.tv_sec = -1;
+    r.tv_nsec += S;
+  }
+  r.tv_sec = r.tv_sec + (a.tv_sec - b.tv_sec);
+  if (r.tv_sec > 2) return UINT_MAX;
+  unsigned int result = (r.tv_sec * S) + r.tv_nsec;
+  if (result > 2 * S) return UINT_MAX;
+  return result;
+}
+
+}
+
+ResourceTimer::ResourceTimer(Counter api)
+    : active_(enabled_.load()),
+      api_(api) {
+  if (active_) {
+    clock_gettime(CLOCK_MONOTONIC, &start_);
+  }
+}
+
+ResourceTimer::~ResourceTimer() {
+  record();
+}
+
+void ResourceTimer::enable() {
+  if (!enabled_.load()) counter_ = new GuardedTimer[ResourceTimer::counterSize];
+  enabled_.store(true);
+}
+
+void ResourceTimer::cancel() {
+  active_ = false;
+}
+
+void ResourceTimer::record() {
+  if (!active_) return;
+
+  struct timespec end;
+  clock_gettime(CLOCK_MONOTONIC, &end);
+  // Get the difference in microseconds.
+  const unsigned int ticks = diffInNs(end, start_);
+  ScopedTimer t(counter_[toIndex(api_)]);
+  t->record(ticks);
+  active_ = false;
+}
+
+bool ResourceTimer::copy(int counter, Timer &dst, bool reset) {
+  ScopedTimer t(counter_[counter]);
+  if (t->count == 0) {
+    dst.reset();
+    if (reset) t->reset();
+    return false;
+  }
+  Timer::copy(dst, *t, reset);
+  return true;
+}
+
+void ResourceTimer::reset() {
+  for (int i = 0; i < counterSize; i++) {
+    ScopedTimer t(counter_[i]);
+    t->reset();
+  }
+}
+
+ResourceTimer::Timer::Timer() {
+  // Ensure newly-created objects are zeroed.
+  memset(buckets, 0, sizeof(buckets));
+  reset();
+}
+
+ResourceTimer::Timer::~Timer() {
+  for (int d = 0; d < MaxDimension; d++) {
+    delete[] buckets[d];
+  }
+}
+
+void ResourceTimer::Timer::freeBuckets() {
+  for (int d = 0; d < MaxDimension; d++) {
+    delete[] buckets[d];
+    buckets[d] = 0;
+  }
+}
+
+void ResourceTimer::Timer::reset() {
+  count = total = mintime = maxtime = 0;
+  memset(largest, 0, sizeof(largest));
+  memset(&pvalues, 0, sizeof(pvalues));
+  // Zero the histogram, keeping any allocated dimensions.
+  for (int d = 0; d < MaxDimension; d++) {
+    if (buckets[d] != 0) memset(buckets[d], 0, sizeof(int) * MaxBuckets);
+  }
+}
+
+void ResourceTimer::Timer::copy(Timer &dst, Timer &src, bool reset) {
+  dst.freeBuckets();
+  dst = src;
+  // Clean up the histograms.
+  if (reset) {
+    // Do NOT free the src buckets because they being used by dst.
+    memset(src.buckets, 0, sizeof(src.buckets));
+    src.reset();
+  } else {
+    for (int d = 0; d < MaxDimension; d++) {
+      if (src.buckets[d] != nullptr) {
+        dst.buckets[d] = new int[MaxBuckets];
+        memcpy(dst.buckets[d], src.buckets[d], sizeof(int) * MaxBuckets);
+      }
+    }
+  }
+}
+
+void ResourceTimer::Timer::record(int ticks) {
+  // Record that the event happened.
+  count++;
+
+  total += ticks;
+  if (mintime == 0 || ticks < mintime) mintime = ticks;
+  if (ticks > maxtime) maxtime = ticks;
+
+  // Do not add oversized events to the histogram.
+  if (ticks != UINT_MAX) {
+    for (int d = 0; d < MaxDimension; d++) {
+      if (ticks < range[d]) {
+        if (buckets[d] == 0) {
+          buckets[d] = new int[MaxBuckets];
+          memset(buckets[d], 0, sizeof(int) * MaxBuckets);
+        }
+        if (ticks < width[d]) {
+          // Special case: never write to bucket 0 because it complicates the percentile logic.
+          // However, this is always the smallest possible value to it is very unlikely to ever
+          // affect any of the percentile results.
+          buckets[d][1]++;
+        } else {
+          buckets[d][ticks / width[d]]++;
+        }
+        break;
+      }
+    }
+  }
+
+  // The list of largest times is sorted with the biggest value at index 0 and the smallest at
+  // index MaxLargest-1.  The incoming tick count should be added to the array only if it is
+  // larger than the current value at MaxLargest-1.
+  if (ticks > largest[Timer::MaxLargest-1]) {
+    for (size_t i = 0; i < Timer::MaxLargest; i++) {
+      if (ticks > largest[i]) {
+        if (i < Timer::MaxLargest-1) {
+          for (size_t j = Timer::MaxLargest - 1; j > i; j--) {
+            largest[j] = largest[j-1];
+          }
+        }
+        largest[i] = ticks;
+        break;
+      }
+    }
+  }
+}
+
+void ResourceTimer::Timer::Percentile::compute(
+    int cumulative, int current, int count, int width, int time) {
+  nominal = time;
+  nominal_actual = (cumulative * 100) / count;
+  floor = nominal - width;
+  floor_actual = ((cumulative - current) * 100) / count;
+}
+
+void ResourceTimer::Timer::compute() {
+  memset(&pvalues, 0, sizeof(pvalues));
+
+  float l50 = count / 2.0;
+  float l90 = (count * 9.0) / 10.0;
+  float l95 = (count * 95.0) / 100.0;
+  float l99 = (count * 99.0) / 100.0;
+
+  int sum = 0;
+  for (int d = 0; d < MaxDimension; d++) {
+    if (buckets[d] == 0) continue;
+    for (int j = 0; j < MaxBuckets && sum < count; j++) {
+      // Empty buckets don't contribute to the answers.  Skip them.
+      if (buckets[d][j] == 0) continue;
+      sum += buckets[d][j];
+      // A word on indexing.  j is never zero in the following lines.  buckets[0][0] corresponds
+      // to a delay of 0us, which cannot happen.  buckets[n][0], for n > 0 overlaps a value in
+      // buckets[n-1], and the code would have stopped there.
+      if (sum >= l50 && pvalues.p50.nominal == 0) {
+        pvalues.p50.compute(sum, buckets[d][j], count, width[d], j * width[d]);
+      }
+      if (sum >= l90 && pvalues.p90.nominal == 0) {
+        pvalues.p90.compute(sum, buckets[d][j], count, width[d], j * width[d]);
+      }
+      if (sum >= l95 && pvalues.p95.nominal == 0) {
+        pvalues.p95.compute(sum, buckets[d][j], count, width[d], j * width[d]);
+      }
+      if (sum >= l99 && pvalues.p99.nominal == 0) {
+        pvalues.p99.compute(sum, buckets[d][j], count, width[d], j * width[d]);
+      }
+    }
+  }
+}
+
+char const *ResourceTimer::toString(ResourceTimer::Counter counter) {
+  switch (counter) {
+    case Counter::GetResourceValue:
+      return "GetResourceValue";
+    case Counter::RetrieveAttributes:
+      return "RetrieveAttributes";
+  };
+  return "Unknown";
+}
+
+std::atomic<bool> ResourceTimer::enabled_(false);
+std::atomic<ResourceTimer::GuardedTimer *> ResourceTimer::counter_(nullptr);
+
+const int ResourceTimer::Timer::range[] = { 100 * US, 1000 * US, 10*1000 * US, 100*1000 * US };
+const int ResourceTimer::Timer::width[] = {   1 * US,   10 * US,     100 * US,     1000 * US };
+
+
+}  // namespace android