From: Kefu Chai <tchaikov@gmail.com>
Date: Tue, 6 Jan 2015 14:28:27 +0000 (+0800)
Subject: common/PriorityQueue: add test cases for it
X-Git-Tag: v9.0.0~125^2
X-Git-Url: http://git-server-git.apps.pok.os.sepia.ceph.com/?a=commitdiff_plain;h=226b61aa494ee9aba7a7155bb4620d64cca76cdc;p=ceph.git

common/PriorityQueue: add test cases for it
---

diff --git a/src/test/Makefile.am b/src/test/Makefile.am
index d714f1ad719e..4d45743edf6a 100644
--- a/src/test/Makefile.am
+++ b/src/test/Makefile.am
@@ -313,6 +313,12 @@ unittest_histogram_CXXFLAGS = $(UNITTEST_CXXFLAGS)
 unittest_histogram_LDADD = $(UNITTEST_LDADD) $(CEPH_GLOBAL)
 check_PROGRAMS += unittest_histogram
 
+unittest_prioritized_queue_SOURCES = test/common/test_prioritized_queue.cc
+unittest_prioritized_queue_CXXFLAGS = $(UNITTEST_CXXFLAGS)
+unittest_prioritized_queue_LDADD = $(UNITTEST_LDADD) $(CEPH_GLOBAL)
+check_PROGRAMS += unittest_prioritized_queue
+
+
 unittest_str_map_SOURCES = test/common/test_str_map.cc
 unittest_str_map_CXXFLAGS = $(UNITTEST_CXXFLAGS)
 unittest_str_map_LDADD = $(UNITTEST_LDADD) $(CEPH_GLOBAL)
diff --git a/src/test/common/test_prioritized_queue.cc b/src/test/common/test_prioritized_queue.cc
new file mode 100644
index 000000000000..00709a1ecbb2
--- /dev/null
+++ b/src/test/common/test_prioritized_queue.cc
@@ -0,0 +1,248 @@
+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
+// vim: ts=8 sw=2 smarttab
+
+#include "gtest/gtest.h"
+#include "common/PrioritizedQueue.h"
+
+#include <numeric>
+#include <vector>
+
+
+using std::vector;
+
+class PrioritizedQueueTest : public testing::Test
+{
+protected:
+  typedef int Klass;
+  typedef unsigned Item;
+  typedef PrioritizedQueue<Item, Klass> PQ;
+  enum { item_size  = 100, };
+  vector<Item> items;
+
+  virtual void SetUp() {
+    for (int i = 0; i < item_size; i++) {
+      items.push_back(Item(i));
+    }
+    random_shuffle(items.begin(), items.end());
+  }
+  virtual void TearDown() {
+    items.clear();
+  }
+};
+
+TEST_F(PrioritizedQueueTest, capacity) {
+  const unsigned min_cost  = 10;
+  const unsigned max_tokens_per_subqueue = 50;
+  PQ pq(max_tokens_per_subqueue, min_cost);
+  EXPECT_TRUE(pq.empty());
+  EXPECT_EQ(0u, pq.length());
+
+  pq.enqueue_strict(Klass(1), 0, Item(0));
+  EXPECT_FALSE(pq.empty());
+  EXPECT_EQ(1u, pq.length());
+
+  for (int i = 0; i < 3; i++) {
+    pq.enqueue(Klass(1), 0, 10, Item(0));
+  }
+  for (unsigned i = 4; i > 0; i--) {
+    EXPECT_FALSE(pq.empty());
+    EXPECT_EQ(i, pq.length());
+    pq.dequeue();
+  }
+  EXPECT_TRUE(pq.empty());
+  EXPECT_EQ(0u, pq.length());
+}
+
+TEST_F(PrioritizedQueueTest, strict_pq) {
+  const unsigned min_cost = 1;
+  const unsigned max_tokens_per_subqueue = 50;
+  PQ pq(max_tokens_per_subqueue, min_cost);
+  // 0 .. item_size-1
+  for (unsigned i = 0; i < item_size; i++) {
+    unsigned priority = items[i];
+    pq.enqueue_strict(Klass(0), priority, items[i]);
+  }
+  // item_size-1 .. 0
+  for (unsigned i = item_size; i > 0; i--) {
+    Item item = pq.dequeue();
+    unsigned priority = item;
+    EXPECT_EQ(i - 1, priority);
+  }
+}
+
+TEST_F(PrioritizedQueueTest, lowest_among_eligible_otherwise_highest) {
+  // to minimize the effect of `distribute_tokens()`
+  // all eligible items will be assigned with cost of min_cost
+  const unsigned min_cost = 0;
+  const unsigned max_tokens_per_subqueue = 100;
+  PQ pq(max_tokens_per_subqueue, min_cost);
+
+#define ITEM_TO_COST(item_) (item_ % 5 ? min_cost : max_tokens_per_subqueue)
+  unsigned num_low_cost = 0, num_high_cost = 0;
+  for (int i = 0; i < item_size; i++) {
+    const Item& item = items[i];
+    unsigned cost = ITEM_TO_COST(item);
+    unsigned priority = item;
+    if (cost == min_cost) {
+      num_low_cost++;
+    } else {
+      num_high_cost++;
+    }
+    pq.enqueue(Klass(0), priority, cost, item);
+  }
+  // the token in all buckets is 0 at the beginning, so dequeue() should pick
+  // the first one with the highest priority.
+  unsigned highest_priority;
+  {
+    Item item = pq.dequeue();
+    unsigned cost = ITEM_TO_COST(item);
+    unsigned priority = item;
+    if (cost == min_cost) {
+      num_low_cost--;
+    } else {
+      num_high_cost--;
+    }
+    EXPECT_EQ(item_size - 1u, priority);
+    highest_priority = priority;
+  }
+  unsigned lowest_priority = 0;
+  for (unsigned i = 0; i < num_low_cost; i++) {
+    Item item = pq.dequeue();
+    unsigned cost = ITEM_TO_COST(item);
+    unsigned priority = item;
+    EXPECT_EQ(min_cost, cost);
+    EXPECT_GT(priority, lowest_priority);
+    lowest_priority = priority;
+  }
+  for (unsigned i = 0; i < num_high_cost; i++) {
+    Item item = pq.dequeue();
+    unsigned cost = ITEM_TO_COST(item);
+    unsigned priority = item;
+    EXPECT_EQ(max_tokens_per_subqueue, cost);
+    EXPECT_LT(priority, highest_priority);
+    highest_priority = priority;
+  }
+#undef ITEM_TO_COST
+}
+
+static const unsigned num_classes = 4;
+// just a determinitic number
+#define ITEM_TO_CLASS(item_) Klass((item_ + 43) % num_classes)
+
+TEST_F(PrioritizedQueueTest, fairness_by_class) {
+  // dequeue should be fair to all classes in a certain bucket
+  const unsigned min_cost = 1;
+  const unsigned max_tokens_per_subqueue = 50;
+  PQ pq(max_tokens_per_subqueue, min_cost);
+
+  for (int i = 0; i < item_size; i++) {
+    const Item& item = items[i];
+    Klass k = ITEM_TO_CLASS(item);
+    unsigned priority = 0;
+    unsigned cost = 1;
+    pq.enqueue(k, priority, cost, item);
+  }
+  // just sample first 1/2 of the items
+  // if i pick too small a dataset, the result won't be statisitcally
+  // significant. if the sample dataset is too large, it will converge to the
+  // distribution of the full set.
+  vector<unsigned> num_picked_in_class(num_classes, 0u);
+  for (int i = 0; i < item_size / 2; i++) {
+    Item item = pq.dequeue();
+    Klass k = ITEM_TO_CLASS(item);
+    num_picked_in_class[k]++;
+  }
+  unsigned total = std::accumulate(num_picked_in_class.begin(),
+				   num_picked_in_class.end(),
+				   0);
+  float avg = float(total) / num_classes;
+  for (unsigned i = 0; i < num_classes; i++) {
+    EXPECT_NEAR(avg, num_picked_in_class[i], 0.5);
+  }
+}
+
+template <typename T>
+struct Greater {
+  const T rhs;
+  Greater(const T& v) : rhs(v)
+  {}
+  bool operator()(const T& lhs) const {
+    return lhs > rhs;
+  }
+};
+
+TEST_F(PrioritizedQueueTest, remove_by_filter) {
+  const unsigned min_cost = 1;
+  const unsigned max_tokens_per_subqueue = 50;
+  PQ pq(max_tokens_per_subqueue, min_cost);
+
+  const Greater<Item> pred(item_size/2);
+  unsigned num_to_remove = 0;
+  for (unsigned i = 0; i < item_size; i++) {
+    const Item& item = items[i];
+    pq.enqueue(Klass(1), 0, 10, item);
+    if (pred(item)) {
+      num_to_remove++;
+    }
+  }
+  std::list<Item> removed;
+  pq.remove_by_filter(pred, &removed);
+
+  // see if the removed items are expected ones.
+  for (std::list<Item>::iterator it = removed.begin();
+       it != removed.end();
+       ++it) {
+    const Item& item = *it;
+    EXPECT_TRUE(pred(item));
+    items.erase(remove(items.begin(), items.end(), item), items.end());
+  }
+  EXPECT_EQ(num_to_remove, removed.size());
+  EXPECT_EQ(item_size - num_to_remove, pq.length());
+  EXPECT_EQ(item_size - num_to_remove, items.size());
+  // see if the remainder are expeceted also.
+  while (!pq.empty()) {
+    const Item item = pq.dequeue();
+    EXPECT_FALSE(pred(item));
+    items.erase(remove(items.begin(), items.end(), item), items.end());
+  }
+  EXPECT_TRUE(items.empty());
+}
+
+TEST_F(PrioritizedQueueTest, remove_by_class) {
+  const unsigned min_cost = 1;
+  const unsigned max_tokens_per_subqueue = 50;
+  PQ pq(max_tokens_per_subqueue, min_cost);
+  const Klass class_to_remove(2);
+  unsigned num_to_remove = 0;
+  for (int i = 0; i < item_size; i++) {
+    const Item& item = items[i];
+    Klass k = ITEM_TO_CLASS(item);
+    pq.enqueue(k, 0, 0, item);
+    if (k == class_to_remove) {
+      num_to_remove++;
+    }
+  }
+  std::list<Item> removed;
+  pq.remove_by_class(class_to_remove, &removed);
+
+  // see if the removed items are expected ones.
+  for (std::list<Item>::iterator it = removed.begin();
+       it != removed.end();
+       ++it) {
+    const Item& item = *it;
+    Klass k = ITEM_TO_CLASS(item);
+    EXPECT_EQ(class_to_remove, k);
+    items.erase(remove(items.begin(), items.end(), item), items.end());
+  }
+  EXPECT_EQ(num_to_remove, removed.size());
+  EXPECT_EQ(item_size - num_to_remove, pq.length());
+  EXPECT_EQ(item_size - num_to_remove, items.size());
+  // see if the remainder are expeceted also.
+  while (!pq.empty()) {
+    const Item item = pq.dequeue();
+    Klass k = ITEM_TO_CLASS(item);
+    EXPECT_NE(class_to_remove, k);
+    items.erase(remove(items.begin(), items.end(), item), items.end());
+  }
+  EXPECT_TRUE(items.empty());
+}