diff --git a/lm/CMakeLists.txt b/lm/CMakeLists.txt
index 195fc730c..5fca22c71 100644
--- a/lm/CMakeLists.txt
+++ b/lm/CMakeLists.txt
@@ -71,7 +71,7 @@ foreach(exe ${EXE_LIST})
   add_executable(${exe} ${exe}_main.cc $<TARGET_OBJECTS:kenlm> $<TARGET_OBJECTS:kenlm_util>)
 
   # Link the executable against boost
-  target_link_libraries(${exe} ${Boost_LIBRARIES})
+  target_link_libraries(${exe} ${Boost_LIBRARIES} pthread)
 
   # Group executables together
   set_target_properties(${exe} PROPERTIES FOLDER executables)
@@ -104,7 +104,7 @@ if(BUILD_TESTING)
       set_target_properties(${test} PROPERTIES COMPILE_FLAGS -DBOOST_TEST_DYN_LINK)
   
       # Link the executable against boost
-      target_link_libraries(${test} ${Boost_LIBRARIES})
+      target_link_libraries(${test} ${Boost_LIBRARIES} pthread)
 
       # model_test requires an extra command line parameter
       if ("${test}" STREQUAL "model_test")
diff --git a/lm/builder/CMakeLists.txt b/lm/builder/CMakeLists.txt
index d84a7f7da..01b415da2 100644
--- a/lm/builder/CMakeLists.txt
+++ b/lm/builder/CMakeLists.txt
@@ -45,7 +45,7 @@ add_library(kenlm_builder OBJECT ${KENLM_BUILDER_SOURCE})
 add_executable(lmplz lmplz_main.cc $<TARGET_OBJECTS:kenlm> $<TARGET_OBJECTS:kenlm_common> $<TARGET_OBJECTS:kenlm_builder> $<TARGET_OBJECTS:kenlm_util>)
 
 # Link the executable against boost
-target_link_libraries(lmplz ${Boost_LIBRARIES})
+target_link_libraries(lmplz ${Boost_LIBRARIES} pthread)
 
 # Group executables together
 set_target_properties(lmplz PROPERTIES FOLDER executables)
@@ -68,7 +68,7 @@ if(BUILD_TESTING)
       set_target_properties(${test} PROPERTIES COMPILE_FLAGS "-DBOOST_TEST_DYN_LINK -DBOOST_PROGRAM_OPTIONS_DYN_LINK")
   
       # Link the executable against boost
-      target_link_libraries(${test} ${Boost_LIBRARIES})
+      target_link_libraries(${test} ${Boost_LIBRARIES} pthread)
       
       # Specify command arguments for how to run each unit test
       #
diff --git a/lm/builder/interpolate.cc b/lm/builder/interpolate.cc
index 6374bcf04..a62ef43d2 100644
--- a/lm/builder/interpolate.cc
+++ b/lm/builder/interpolate.cc
@@ -9,6 +9,7 @@
 #include "util/fixed_array.hh"
 #include "util/murmur_hash.hh"
 
+#include <iostream>
 #include <cassert>
 #include <cmath>
 
diff --git a/lm/builder/pipeline.cc b/lm/builder/pipeline.cc
index 69972e278..64e30f724 100644
--- a/lm/builder/pipeline.cc
+++ b/lm/builder/pipeline.cc
@@ -191,6 +191,9 @@ class Master {
       chains_.clear();
       std::cerr << "Chain sizes:";
       for (std::size_t i = 0; i < config_.order; ++i) {
+        // Always have enough for at least one record.
+        // This was crashing if e.g. there was no 5-gram.
+        assignments[i] = std::max(assignments[i], block_count[i] * NGram<BuildingPayload>::TotalSize(i + 1));
         std::cerr << ' ' << (i+1) << ":" << assignments[i];
         chains_.push_back(util::stream::ChainConfig(NGram<BuildingPayload>::TotalSize(i + 1), block_count[i], assignments[i]));
       }
diff --git a/lm/filter/CMakeLists.txt b/lm/filter/CMakeLists.txt
index 4e791cef8..d4616cc32 100644
--- a/lm/filter/CMakeLists.txt
+++ b/lm/filter/CMakeLists.txt
@@ -52,7 +52,7 @@ foreach(exe ${EXE_LIST})
 	add_executable(${exe} ${exe}_main.cc $<TARGET_OBJECTS:kenlm> $<TARGET_OBJECTS:kenlm_filter> $<TARGET_OBJECTS:kenlm_util>)
 
   # Link the executable against boost
-  target_link_libraries(${exe} ${Boost_LIBRARIES})
+  target_link_libraries(${exe} ${Boost_LIBRARIES} pthread)
 
   # Group executables together
   set_target_properties(${exe} PROPERTIES FOLDER executables)
diff --git a/lm/kenlm_benchmark_main.cc b/lm/kenlm_benchmark_main.cc
index d8b659139..1704ec6c9 100644
--- a/lm/kenlm_benchmark_main.cc
+++ b/lm/kenlm_benchmark_main.cc
@@ -31,9 +31,7 @@ template <class Model, class Width> void QueryFromBytes(const Model &model, int
   Width kEOS = model.GetVocabulary().EndSentence();
   Width buf[4096];
   float sum = 0.0;
-  while (true) {
-    std::size_t got = util::ReadOrEOF(fd_in, buf, sizeof(buf));
-    if (!got) break;
+  while (std::size_t got = util::ReadOrEOF(fd_in, buf, sizeof(buf))) {
     UTIL_THROW_IF2(got % sizeof(Width), "File size not a multiple of vocab id size " << sizeof(Width));
     got /= sizeof(Width);
     // Do even stuff first.
diff --git a/util/CMakeLists.txt b/util/CMakeLists.txt
index c52cdbc06..6f7f5e99b 100644
--- a/util/CMakeLists.txt
+++ b/util/CMakeLists.txt
@@ -80,7 +80,7 @@ if(BUILD_TESTING)
       set_target_properties(${test} PROPERTIES COMPILE_FLAGS -DBOOST_TEST_DYN_LINK)
   
       # Link the executable against boost
-      target_link_libraries(${test} ${Boost_LIBRARIES})
+      target_link_libraries(${test} ${Boost_LIBRARIES} pthread)
 
       # file_piece_test requires an extra command line parameter
       if ("${test}" STREQUAL "file_piece_test")
diff --git a/util/fixed_array.hh b/util/fixed_array.hh
index 9083d39ee..c67e8ed95 100644
--- a/util/fixed_array.hh
+++ b/util/fixed_array.hh
@@ -11,10 +11,10 @@
 namespace util {
 
 /**
- * Defines a fixed-size collection.
+ * Defines an array with fixed maximum size.
  *
- * Ever want an array of things by they don't have a default constructor or are
- * non-copyable?  FixedArray allows constructing one at a time.
+ * Ever want an array of things but they don't have a default constructor or
+ * are non-copyable?  FixedArray allows constructing one at a time.
  */
 template <class T> class FixedArray {
   public:
diff --git a/util/probing_hash_table.hh b/util/probing_hash_table.hh
index f32b64ea3..53fbbe996 100644
--- a/util/probing_hash_table.hh
+++ b/util/probing_hash_table.hh
@@ -26,6 +26,65 @@ struct IdentityHash {
   template <class T> T operator()(T arg) const { return arg; }
 };
 
+class DivMod {
+  public:
+    explicit DivMod(std::size_t buckets) : buckets_(buckets) {}
+
+    static std::size_t RoundBuckets(std::size_t from) {
+      return from;
+    }
+
+    template <class It> It Ideal(It begin, uint64_t hash) const {
+      return begin + (hash % buckets_);
+    }
+
+    template <class BaseIt, class OutIt> void Next(BaseIt begin, BaseIt end, OutIt &it) const {
+      if (++it == end) it = begin;
+    }
+
+    void Double() {
+      buckets_ *= 2;
+    }
+
+  private:
+    std::size_t buckets_;
+};
+
+class Power2Mod {
+  public:
+    explicit Power2Mod(std::size_t buckets) {
+      UTIL_THROW_IF(!buckets || (((buckets - 1) & buckets)), ProbingSizeException, "Size " << buckets << " is not a power of 2.");
+      mask_ = buckets - 1;
+    }
+
+    // Round up to next power of 2.
+    static std::size_t RoundBuckets(std::size_t from) {
+      --from;
+      from |= from >> 1;
+      from |= from >> 2;
+      from |= from >> 4;
+      from |= from >> 8;
+      from |= from >> 16;
+      from |= from >> 32;
+      return from + 1;
+    }
+
+    template <class It> It Ideal(It begin, uint64_t hash) const {
+      return begin + (hash & mask_);
+    }
+
+    template <class BaseIt, class OutIt> void Next(BaseIt begin, BaseIt /*end*/, OutIt &it) const {
+      it = begin + ((it - begin + 1) & mask_);
+    }
+
+    void Double() {
+      mask_ = (mask_ << 1) | 1;
+    }
+
+  private:
+    std::size_t mask_;
+};
+
 template <class EntryT, class HashT, class EqualT> class AutoProbing;
 
 /* Non-standard hash table
@@ -36,7 +95,7 @@ template <class EntryT, class HashT, class EqualT> class AutoProbing;
  * Uses linear probing to find value.
  * Only insert and lookup operations.
  */
-template <class EntryT, class HashT, class EqualT = std::equal_to<typename EntryT::Key> > class ProbingHashTable {
+template <class EntryT, class HashT, class EqualT = std::equal_to<typename EntryT::Key>, class ModT = DivMod> class ProbingHashTable {
   public:
     typedef EntryT Entry;
     typedef typename Entry::Key Key;
@@ -44,14 +103,15 @@ template <class EntryT, class HashT, class EqualT = std::equal_to<typename Entry
     typedef Entry *MutableIterator;
     typedef HashT Hash;
     typedef EqualT Equal;
+    typedef ModT Mod;
 
     static uint64_t Size(uint64_t entries, float multiplier) {
-      uint64_t buckets = std::max(entries + 1, static_cast<uint64_t>(multiplier * static_cast<float>(entries)));
+      uint64_t buckets = Mod::RoundBuckets(std::max(entries + 1, static_cast<uint64_t>(multiplier * static_cast<float>(entries))));
       return buckets * sizeof(Entry);
     }
 
     // Must be assigned to later.
-    ProbingHashTable() : entries_(0)
+    ProbingHashTable() : mod_(1), entries_(0)
 #ifdef DEBUG
       , initialized_(false)
 #endif
@@ -59,11 +119,12 @@ template <class EntryT, class HashT, class EqualT = std::equal_to<typename Entry
 
     ProbingHashTable(void *start, std::size_t allocated, const Key &invalid = Key(), const Hash &hash_func = Hash(), const Equal &equal_func = Equal())
       : begin_(reinterpret_cast<MutableIterator>(start)),
-        buckets_(allocated / sizeof(Entry)),
-        end_(begin_ + buckets_),
+        end_(begin_ + allocated / sizeof(Entry)),
+        buckets_(end_ - begin_),
         invalid_(invalid),
         hash_(hash_func),
         equal_(equal_func),
+        mod_(end_ - begin_),
         entries_(0)
 #ifdef DEBUG
         , initialized_(true)
@@ -75,6 +136,13 @@ template <class EntryT, class HashT, class EqualT = std::equal_to<typename Entry
       end_ = begin_ + buckets_;
     }
 
+    MutableIterator Ideal(const Key key) {
+      return mod_.Ideal(begin_, hash_(key));
+    }
+    ConstIterator Ideal(const Key key) const {
+      return mod_.Ideal(begin_, hash_(key));
+    }
+
     template <class T> MutableIterator Insert(const T &t) {
 #ifdef DEBUG
       assert(initialized_);
@@ -83,12 +151,12 @@ template <class EntryT, class HashT, class EqualT = std::equal_to<typename Entry
       return UncheckedInsert(t);
     }
 
-    // Return true if the value was found (and not inserted).  This is consistent with Find but the opposite if hash_map!
+    // Return true if the value was found (and not inserted).  This is consistent with Find but the opposite of hash_map!
     template <class T> bool FindOrInsert(const T &t, MutableIterator &out) {
 #ifdef DEBUG
       assert(initialized_);
 #endif
-      for (MutableIterator i = Ideal(t.GetKey());;) {
+      for (MutableIterator i = Ideal(t.GetKey());;mod_.Next(begin_, end_, i)) {
         Key got(i->GetKey());
         if (equal_(got, t.GetKey())) { out = i; return true; }
         if (equal_(got, invalid_)) {
@@ -97,7 +165,6 @@ template <class EntryT, class HashT, class EqualT = std::equal_to<typename Entry
           out = i;
           return false;
         }
-        if (++i == end_) i = begin_;
       }
     }
 
@@ -108,44 +175,45 @@ template <class EntryT, class HashT, class EqualT = std::equal_to<typename Entry
 #ifdef DEBUG
       assert(initialized_);
 #endif
-      for (MutableIterator i(Ideal(key));;) {
+      for (MutableIterator i(Ideal(key));; mod_.Next(begin_, end_, i)) {
         Key got(i->GetKey());
         if (equal_(got, key)) { out = i; return true; }
         if (equal_(got, invalid_)) return false;
-        if (++i == end_) i = begin_;
       }
     }
 
     // Like UnsafeMutableFind, but the key must be there.
     template <class Key> MutableIterator UnsafeMutableMustFind(const Key key) {
-       for (MutableIterator i(Ideal(key));;) {
+      for (MutableIterator i(Ideal(key));; mod_.Next(begin_, end_, i)) {
         Key got(i->GetKey());
         if (equal_(got, key)) { return i; }
         assert(!equal_(got, invalid_));
-        if (++i == end_) i = begin_;
       }
     }
 
-
-    template <class Key> bool Find(const Key key, ConstIterator &out) const {
+    // Iterator is both input and output.
+    template <class Key> bool FindFromIdeal(const Key key, ConstIterator &i) const {
 #ifdef DEBUG
       assert(initialized_);
 #endif
-      for (ConstIterator i(Ideal(key));;) {
+      for (;; mod_.Next(begin_, end_, i)) {
         Key got(i->GetKey());
-        if (equal_(got, key)) { out = i; return true; }
+        if (equal_(got, key)) return true;
         if (equal_(got, invalid_)) return false;
-        if (++i == end_) i = begin_;
       }
     }
 
+    template <class Key> bool Find(const Key key, ConstIterator &out) const {
+      out = Ideal(key);
+      return FindFromIdeal(key, out);
+    }
+
     // Like Find but we're sure it must be there.
     template <class Key> ConstIterator MustFind(const Key key) const {
-      for (ConstIterator i(Ideal(key));;) {
+      for (ConstIterator i(Ideal(key));; mod_.Next(begin_, end_, i)) {
         Key got(i->GetKey());
         if (equal_(got, key)) { return i; }
         assert(!equal_(got, invalid_));
-        if (++i == end_) i = begin_;
       }
     }
 
@@ -174,6 +242,7 @@ template <class EntryT, class HashT, class EqualT = std::equal_to<typename Entry
       MutableIterator old_end = begin_ + buckets_;
       buckets_ *= 2;
       end_ = begin_ + buckets_;
+      mod_.Double();
       if (clear_new) {
         Entry invalid;
         invalid.SetKey(invalid_);
@@ -230,26 +299,20 @@ template <class EntryT, class HashT, class EqualT = std::equal_to<typename Entry
   private:
     friend class AutoProbing<Entry, Hash, Equal>;
 
-    MutableIterator Ideal(const Key key) {
-      return begin_ + (hash_(key) % buckets_);
-    }
-    ConstIterator Ideal(const Key key) const {
-      return begin_ + (hash_(key) % buckets_);
-    }
-
     template <class T> MutableIterator UncheckedInsert(const T &t) {
-      for (MutableIterator i(Ideal(t.GetKey()));;) {
+      for (MutableIterator i(Ideal(t.GetKey()));; mod_.Next(begin_, end_, i)) {
         if (equal_(i->GetKey(), invalid_)) { *i = t; return i; }
-        if (++i == end_) { i = begin_; }
       }
     }
 
     MutableIterator begin_;
-    std::size_t buckets_;
     MutableIterator end_;
+    std::size_t buckets_;
     Key invalid_;
     Hash hash_;
     Equal equal_;
+    Mod mod_;
+
     std::size_t entries_;
 #ifdef DEBUG
     bool initialized_;
@@ -259,7 +322,7 @@ template <class EntryT, class HashT, class EqualT = std::equal_to<typename Entry
 // Resizable linear probing hash table.  This owns the memory.
 template <class EntryT, class HashT, class EqualT = std::equal_to<typename EntryT::Key> > class AutoProbing {
   private:
-    typedef ProbingHashTable<EntryT, HashT, EqualT> Backend;
+    typedef ProbingHashTable<EntryT, HashT, EqualT, Power2Mod> Backend;
   public:
     static std::size_t MemUsage(std::size_t size, float multiplier = 1.5) {
       return Backend::Size(size, multiplier);
@@ -272,7 +335,7 @@ template <class EntryT, class HashT, class EqualT = std::equal_to<typename Entry
     typedef HashT Hash;
     typedef EqualT Equal;
 
-    AutoProbing(std::size_t initial_size = 10, const Key &invalid = Key(), const Hash &hash_func = Hash(), const Equal &equal_func = Equal()) :
+    AutoProbing(std::size_t initial_size = 5, const Key &invalid = Key(), const Hash &hash_func = Hash(), const Equal &equal_func = Equal()) :
       allocated_(Backend::Size(initial_size, 1.5)), mem_(util::MallocOrThrow(allocated_)), backend_(mem_.get(), allocated_, invalid, hash_func, equal_func) {
       threshold_ = initial_size * 1.2;
       Clear();
diff --git a/util/probing_hash_table_benchmark_main.cc b/util/probing_hash_table_benchmark_main.cc
index 3e12290cf..c5129480f 100644
--- a/util/probing_hash_table_benchmark_main.cc
+++ b/util/probing_hash_table_benchmark_main.cc
@@ -1,10 +1,8 @@
+#include "util/file.hh"
 #include "util/probing_hash_table.hh"
 #include "util/scoped.hh"
 #include "util/usage.hh"
 
-#include <boost/random/mersenne_twister.hpp>
-#include <boost/random/uniform_int_distribution.hpp>
-
 #include <iostream>
 
 namespace util {
@@ -16,34 +14,143 @@ struct Entry {
   Key GetKey() const { return key; }
 };
 
-typedef util::ProbingHashTable<Entry, util::IdentityHash> Table;
+// I don't care if this doesn't run on Windows.  Empirically /dev/urandom was faster than boost::random's Mersenne Twister.
+class URandom {
+  public:
+    URandom() :
+      it_(buf_ + 1024), end_(buf_ + 1024),
+      file_(util::OpenReadOrThrow("/dev/urandom")) {}
 
-void Test(uint64_t entries, uint64_t lookups, float multiplier = 1.5) {
-  std::size_t size = Table::Size(entries, multiplier);
+    uint64_t Get() {
+      if (it_ == end_) {
+        it_ = buf_;
+        util::ReadOrThrow(file_.get(), buf_, sizeof(buf_));
+        it_ = buf_;
+      }
+      return *it_++;
+    }
+
+    void Batch(uint64_t *begin, uint64_t *end) {
+      util::ReadOrThrow(file_.get(), begin, (end - begin) * sizeof(uint64_t));
+    }
+
+  private:
+    uint64_t buf_[1024];
+    uint64_t *it_, *end_;
+
+    util::scoped_fd file_;
+};
+
+struct PrefetchEntry {
+  uint64_t key;
+  const Entry *pointer;
+};
+
+const std::size_t kPrefetchSize = 4;
+template <class Table> class PrefetchQueue {
+  public:
+    explicit PrefetchQueue(Table &table) : table_(table), cur_(0), twiddle_(false) {
+      for (PrefetchEntry *i = entries_; i != entries_ + kPrefetchSize; ++i)
+        i->pointer = NULL;
+    }
+
+    void Add(uint64_t key) {
+      if (Cur().pointer) {
+        twiddle_ ^= table_.FindFromIdeal(Cur().key, Cur().pointer);
+      }
+      Cur().key = key;
+      Cur().pointer = table_.Ideal(key);
+      __builtin_prefetch(Cur().pointer, 0, 0);
+      Next();
+    }
+
+    bool Drain() {
+      if (Cur().pointer) {
+        for (PrefetchEntry *i = &Cur(); i < entries_ + kPrefetchSize; ++i) {
+          twiddle_ ^= table_.FindFromIdeal(i->key, i->pointer);
+        }
+      }
+      for (PrefetchEntry *i = entries_; i < &Cur(); ++i) {
+        twiddle_ ^= table_.FindFromIdeal(i->key, i->pointer);
+      }
+      return twiddle_;
+    }
+
+  private:
+    PrefetchEntry &Cur() { return entries_[cur_]; }
+    void Next() {
+      ++cur_;
+      cur_ = cur_ % kPrefetchSize;
+    }
+
+    Table &table_;
+    PrefetchEntry entries_[kPrefetchSize];
+    std::size_t cur_;
+
+    bool twiddle_;
+
+    PrefetchQueue(const PrefetchQueue&);
+    void operator=(const PrefetchQueue&);
+};
+
+/*template <class Table> class Immediate {
+  public:
+
+  private:
+    Table &table_;
+};*/
+
+std::size_t Size(uint64_t entries, float multiplier = 1.5) {
+  typedef util::ProbingHashTable<Entry, util::IdentityHash, std::equal_to<Entry::Key>, Power2Mod> Table;
+  // Always round up to power of 2 for fair comparison.
+  return Power2Mod::RoundBuckets(Table::Size(entries, multiplier) / sizeof(Entry)) * sizeof(Entry);
+}
+
+template <class Mod> bool Test(URandom &rn, uint64_t entries, const uint64_t *const queries_begin, const uint64_t *const queries_end, float multiplier = 1.5) {
+  typedef util::ProbingHashTable<Entry, util::IdentityHash, std::equal_to<Entry::Key>, Mod> Table;
+  std::size_t size = Size(entries, multiplier);
   scoped_malloc backing(util::CallocOrThrow(size));
   Table table(backing.get(), size);
-  boost::random::mt19937 gen;
-  boost::random::uniform_int_distribution<> dist(std::numeric_limits<uint64_t>::min(), std::numeric_limits<uint64_t>::max());
+
   double start = UserTime();
   for (uint64_t i = 0; i < entries; ++i) {
     Entry entry;
-    entry.key = dist(gen);
+    entry.key = rn.Get();
     table.Insert(entry);
   }
-  double inserted = UserTime();
-  bool meaningless = true;
-  for (uint64_t i = 0; i < lookups; ++i) {
-    Table::ConstIterator it;
-    meaningless ^= table.Find(dist(gen), it);
+  double inserted = UserTime() - start;
+  double before_lookup = UserTime();
+  PrefetchQueue<Table> queue(table);
+  for (const uint64_t *i = queries_begin; i != queries_end; ++i) {
+    queue.Add(*i);
+/*    typename Table::ConstIterator it;
+    meaningless ^= table.Find(*i, it);*/
   }
-  std::cout << meaningless << ' ' << entries << ' ' << multiplier << ' ' << (inserted - start) << ' ' << (UserTime() - inserted) / static_cast<double>(lookups) << std::endl;
+  bool meaningless = queue.Drain();
+  std::cout << entries << ' ' << size << ' ' << (inserted / static_cast<double>(entries)) << ' ' << (UserTime() - before_lookup) / static_cast<double>(queries_end - queries_begin) << '\n';
+  return meaningless;
+}
+
+template <class Mod> bool TestRun(uint64_t lookups = 20000000, float multiplier = 1.5) {
+  URandom rn;
+  util::scoped_malloc queries(util::CallocOrThrow(lookups * sizeof(uint64_t)));
+  rn.Batch(static_cast<uint64_t*>(queries.get()), static_cast<uint64_t*>(queries.get()) + lookups);
+  uint64_t physical_mem_limit = util::GuessPhysicalMemory() / 2;
+  bool meaningless = true;
+  for (uint64_t i = 4; Size(i / multiplier) < physical_mem_limit; i *= 4) {
+    meaningless ^= util::Test<Mod>(rn, i / multiplier, static_cast<const uint64_t*>(queries.get()), static_cast<const uint64_t*>(queries.get()) + lookups, multiplier);
+  }
+  return meaningless;
 }
 
 } // namespace
 } // namespace util
 
 int main() {
-  for (uint64_t i = 1; i <= 10000000ULL; i *= 10) {
-    util::Test(i, 10000000);
-  }
+  bool meaningless = false;
+  std::cout << "#Integer division\n";
+  meaningless ^= util::TestRun<util::DivMod>();
+  std::cout << "#Masking\n";
+  meaningless ^= util::TestRun<util::Power2Mod>();
+  std::cerr << "Meaningless: " << meaningless << '\n';
 }
diff --git a/util/stream/CMakeLists.txt b/util/stream/CMakeLists.txt
index d3eddbe5c..3e47f73e6 100644
--- a/util/stream/CMakeLists.txt
+++ b/util/stream/CMakeLists.txt
@@ -55,7 +55,7 @@ if(BUILD_TESTING)
       set_target_properties(${test} PROPERTIES COMPILE_FLAGS -DBOOST_TEST_DYN_LINK)
   
       # Link the executable against boost
-      target_link_libraries(${test} ${Boost_LIBRARIES})
+      target_link_libraries(${test} ${Boost_LIBRARIES} pthread)
       
       # Specify command arguments for how to run each unit test
       #
diff --git a/util/stream/rewindable_stream.cc b/util/stream/rewindable_stream.cc
index 2867bf8ab..726e2a72d 100644
--- a/util/stream/rewindable_stream.cc
+++ b/util/stream/rewindable_stream.cc
@@ -1,6 +1,8 @@
 #include "util/stream/rewindable_stream.hh"
 #include "util/pcqueue.hh"
 
+#include <iostream>
+
 namespace util {
 namespace stream {