[libc][math] Improved ExhaustiveTest performance.

[orex]

Summary

Previous implementation splits value ranges around threads. Because of
very different performance of testing functions over different ranges,
CPU utilization were poor. Current implementation split test range
over small pieces and threads take the pieces when they finish with
previous. Therefore the CPU load is constant during testing.

[lntue]

libc/test/src/math/exhaustive/exhaustive_test.cpp

39–41

This might be overflow when stop < increment, since both are unsigned?

51

It is actually convenient to display the tested range whether it passed or not, so that we can save time by only running the failed ranges again while developing. Also if you build the message separately before passing all at once to std::cout, you will not need this lock, since a single << for std::cout is guaranteed to be atomic.

libc/test/src/math/exhaustive/exhaustive_test.h

20

Probably this should be configurable from the caller side. Few possibilities:

1. add increment to the last parameter of test_full_range with default value.
2. move rounding mode to a template parameter of test_full_range and add increment to the last parameter of test_full_range with default value.
3. add increment to as a template parameter of test_full_range with default value.
4. add both rounding mode and increment to template parameters of test_full_range with default value for increment.

Among these, I think option 2 will make the caller sides look the best. What do you think?

[orex]

libc/test/src/math/exhaustive/exhaustive_test.cpp

39–41

Agree. Thank you.

51

That will be a lot of ranges, which is passed. I don't think it will be good to display them. Also you always have a values, which is not passed from testing macros, so you can use them to check problems.

[lntue]

libc/test/src/math/exhaustive/exhaustive_test.cpp

51

Or just display the failed ranges? So that you can redirect the outputs to a file and find the exact / smallest ranges to skip all the passed one? Actually with your default option, 2^12 ranges is not too bad for output to a file.

[orex]

Fix some reviewer comments.

[orex]

libc/test/src/math/exhaustive/exhaustive_test.cpp

51

Good proposition. Done.

libc/test/src/math/exhaustive/exhaustive_test.h

20

I can hardly imagine, that developers in general should take care about this. It looks like a technical thing. Anyhow I understand you point. I propose another solution. Make it virtual function, which default value in base class. If you would like to change the parameter, you can overload the function together with check function, which you should overload. What do you think?

About the template parameter of rounding. It is a good idea, but probably, we can think about to do all rounding and ranges with one command? Also, it is good to combine everything in one function like exec?
And you pass ranges and rounding as overload functions in check implementation class?

So, in derivative class you overload array of rounding, array of ranges and check function, of course.

But, let's do as you always said several small steps.)))))

libc/test/src/math/exhaustive/exhaustive_test.h

 // To test exhaustively for inputs in the range [start, stop) in parallel:
 // 1. Inherit from LlvmLibcExhaustiveTest class
 // 2. Overide the test method: void check(T, T, RoundingMode)
 // 4. Call: test_full_range(start, stop, nthreads, rounding)
 namespace mpfr = __llvm_libc::testing::mpfr;
 
 template <typename T>
 struct LlvmLibcExhaustiveTest : public __llvm_libc::testing::Test {
+  static constexpr T increment = (1 << 20);
   // Break [start, stop) into `nthreads` subintervals and apply *check to each
   // subinterval in parallel.
-  void test_full_range(T start, T stop, int nthreads,
-                       mpfr::RoundingMode rounding);
+  void test_full_range(T start, T stop, mpfr::RoundingMode rounding);
 
   virtual bool check(T start, T stop, mpfr::RoundingMode rounding) = 0;
 };

libc/test/src/math/exhaustive/exhaustive_test.cpp

 //===-- Exhaustive test template for math functions -------------*- C++ -*-===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
+#include <atomic>
 #include <fenv.h>
 #include <functional>
 #include <iostream>
-#include <sstream>
-#include <string>
+#include <mutex>
 #include <thread>
 #include <vector>
 
 #include "exhaustive_test.h"
-#include "src/__support/FPUtil/FPBits.h"
-#include "utils/UnitTest/Test.h"
 
 template <typename T>
-void LlvmLibcExhaustiveTest<T>::test_full_range(T start, T stop, int nthreads,
+void LlvmLibcExhaustiveTest<T>::test_full_range(T start, T stop,
                                                 mpfr::RoundingMode rounding) {
-  std::vector<std::thread> thread_list(nthreads);
-  T increment = (stop - start - 1) / nthreads + 1;
-  T begin = start;
-  T end = start + increment - 1;
-  for (int i = 0; i < nthreads; ++i) {
-    thread_list.emplace_back([this, begin, end, rounding]() {
-      std::stringstream msg;
-      msg << "-- Testing from " << begin << " to " << end << " [0x" << std::hex
-          << begin << ", 0x" << end << "), [" << std::hexfloat
-          << float(__llvm_libc::fputil::FPBits<float>(
-                 static_cast<uint32_t>(begin)))
-          << ", "
-          << float(
-                 __llvm_libc::fputil::FPBits<float>(static_cast<uint32_t>(end)))
-          << ") ..." << std::endl;
-      std::cout << msg.str();
-      msg.str("");
-
-      bool result = check(begin, end, rounding);
-
-      msg << "** Finished testing from " << std::dec << begin << " to " << end
-          << " [0x" << std::hex << begin << ", 0x" << end << "), ["
-          << std::hexfloat
-          << float(__llvm_libc::fputil::FPBits<float>(
-                 static_cast<uint32_t>(begin)))
-          << ", "
-          << float(
-                 __llvm_libc::fputil::FPBits<float>(static_cast<uint32_t>(end)))
-          << ") : " << (result ? "PASSED" : "FAILED") << std::endl;
-      std::cout << msg.str();
+  int n_threads = std::thread::hardware_concurrency();
+  std::vector<std::thread> thread_list;
+  std::mutex mx_cur_val, mx_cout;
+  int current_percent = -1;
+  T current_value = start;
+  std::atomic<uint64_t> failed(0);
+  for (int i = 0; i < n_threads; ++i) {
+    thread_list.emplace_back([&, this]() {
+      while (true) {
+        T range_begin, range_end;
+        int new_percent = -1;
+        {
+          std::lock_guard<std::mutex> lock(mx_cur_val);
+          if (current_value == stop)
+            return;
+
+          range_begin = current_value;
+          range_end = (stop - increment >= current_value)
+                          ? (current_value + increment)
+                          : stop;
+          current_value = range_end;
+          int pc = 100.0 * double(range_end - start) / double(stop - start);
+          if (current_percent != pc) {
+            new_percent = pc;
+            current_percent = pc;
+          }
+        }
+        if (new_percent >= 0) {
+          std::lock_guard<std::mutex> lock(mx_cout);
+          std::cout << new_percent << "% is in process     \r" << std::flush;
+        }
+
+        bool check_passed = check(range_begin, range_end, rounding);
+        if (!check_passed)
+          failed.fetch_add(1);
+      }
     });
-    begin += increment;
-    end += increment;
-    if (end > stop)
-      end = stop;
   }
+
   for (auto &thread : thread_list) {
     if (thread.joinable()) {
       thread.join();
     }
   }
+  std::cout << std::endl;
+  std::cout << "Test " << ((failed > 0) ? "FAILED" : "PASSED") << std::endl;
 }
 
 template void
-LlvmLibcExhaustiveTest<uint32_t>::test_full_range(uint32_t, uint32_t, int,
+    LlvmLibcExhaustiveTest<uint32_t>::test_full_range(uint32_t, uint32_t,
                                                       mpfr::RoundingMode);
 template void
-LlvmLibcExhaustiveTest<uint64_t>::test_full_range(uint64_t, uint64_t, int,
+    LlvmLibcExhaustiveTest<uint64_t>::test_full_range(uint64_t, uint64_t,
                                                       mpfr::RoundingMode);

libc/test/src/math/exhaustive/exp2f_test.cpp

do {
       float x = float(xbits);
       result &= EXPECT_MPFR_MATCH(mpfr::Operation::Exp2, x,
                                   __llvm_libc::exp2f(x), 0.5, rounding);
     } while (bits++ < stop);
     return result;
   }
 };
 
-static constexpr int NUM_THREADS = 16;
-
 // Range: [0, 128];
 static constexpr uint32_t POS_START = 0x0000'0000U;
 static constexpr uint32_t POS_STOP = 0x4300'0000U;
 
 TEST_F(LlvmLibcExp2fExhaustiveTest, PostiveRangeRoundNearestTieToEven) {
-  test_full_range(POS_START, POS_STOP, NUM_THREADS,
-                  mpfr::RoundingMode::Nearest);
+  test_full_range(POS_START, POS_STOP, mpfr::RoundingMode::Nearest);
 }
 
 TEST_F(LlvmLibcExp2fExhaustiveTest, PostiveRangeRoundUp) {
-  test_full_range(POS_START, POS_STOP, NUM_THREADS, mpfr::RoundingMode::Upward);
+  test_full_range(POS_START, POS_STOP, mpfr::RoundingMode::Upward);
 }
 
 TEST_F(LlvmLibcExp2fExhaustiveTest, PostiveRangeRoundDown) {
-  test_full_range(POS_START, POS_STOP, NUM_THREADS,
-                  mpfr::RoundingMode::Downward);
+  test_full_range(POS_START, POS_STOP, mpfr::RoundingMode::Downward);
 }
 
 TEST_F(LlvmLibcExp2fExhaustiveTest, PostiveRangeRoundTowardZero) {
-  test_full_range(POS_START, POS_STOP, NUM_THREADS,
-                  mpfr::RoundingMode::TowardZero);
+  test_full_range(POS_START, POS_STOP, mpfr::RoundingMode::TowardZero);
 }
 
 // Range: [-150, 0];
 static constexpr uint32_t NEG_START = 0x8000'0000U;
 static constexpr uint32_t NEG_STOP = 0xc316'0000U;
 
 TEST_F(LlvmLibcExp2fExhaustiveTest, NegativeRangeRoundNearestTieToEven) {
-  test_full_range(NEG_START, NEG_STOP, NUM_THREADS,
-                  mpfr::RoundingMode::Nearest);
+  test_full_range(NEG_START, NEG_STOP, mpfr::RoundingMode::Nearest);
 }
 
 TEST_F(LlvmLibcExp2fExhaustiveTest, NegativeRangeRoundUp) {
-  test_full_range(NEG_START, NEG_STOP, NUM_THREADS, mpfr::RoundingMode::Upward);
+  test_full_range(NEG_START, NEG_STOP, mpfr::RoundingMode::Upward);
 }
 
 TEST_F(LlvmLibcExp2fExhaustiveTest, NegativeRangeRoundDown) {
-  test_full_range(NEG_START, NEG_STOP, NUM_THREADS,
-                  mpfr::RoundingMode::Downward);
+  test_full_range(NEG_START, NEG_STOP, mpfr::RoundingMode::Downward);
 }
 
 TEST_F(LlvmLibcExp2fExhaustiveTest, NegativeRangeRoundTowardZero) {
-  test_full_range(NEG_START, NEG_STOP, NUM_THREADS,
-                  mpfr::RoundingMode::TowardZero);
+  test_full_range(NEG_START, NEG_STOP, mpfr::RoundingMode::TowardZero);
 }

libc/test/src/math/exhaustive/expf_test.cpp

do {
       float x = float(xbits);
       result &= EXPECT_MPFR_MATCH(mpfr::Operation::Exp, x, __llvm_libc::expf(x),
                                   0.5, rounding);
     } while (bits++ < stop);
     return result;
   }
 };
 
-static const int NUM_THREADS = std::thread::hardware_concurrency();
-
 // Range: [0, 89];
 static constexpr uint32_t POS_START = 0x0000'0000U;
 static constexpr uint32_t POS_STOP = 0x42b2'0000U;
 
 TEST_F(LlvmLibcExpfExhaustiveTest, PostiveRangeRoundNearestTieToEven) {
-  test_full_range(POS_START, POS_STOP, NUM_THREADS,
-                  mpfr::RoundingMode::Nearest);
+  test_full_range(POS_START, POS_STOP, mpfr::RoundingMode::Nearest);
 }
 
 TEST_F(LlvmLibcExpfExhaustiveTest, PostiveRangeRoundUp) {
-  test_full_range(POS_START, POS_STOP, NUM_THREADS, mpfr::RoundingMode::Upward);
+  test_full_range(POS_START, POS_STOP, mpfr::RoundingMode::Upward);
 }
 
 TEST_F(LlvmLibcExpfExhaustiveTest, PostiveRangeRoundDown) {
-  test_full_range(POS_START, POS_STOP, NUM_THREADS,
-                  mpfr::RoundingMode::Downward);
+  test_full_range(POS_START, POS_STOP, mpfr::RoundingMode::Downward);
 }
 
 TEST_F(LlvmLibcExpfExhaustiveTest, PostiveRangeRoundTowardZero) {
-  test_full_range(POS_START, POS_STOP, NUM_THREADS,
-                  mpfr::RoundingMode::TowardZero);
+  test_full_range(POS_START, POS_STOP, mpfr::RoundingMode::TowardZero);
 }
 
 // Range: [-104, 0];
 static constexpr uint32_t NEG_START = 0x8000'0000U;
 static constexpr uint32_t NEG_STOP = 0xc2d0'0000U;
 
 TEST_F(LlvmLibcExpfExhaustiveTest, NegativeRangeRoundNearestTieToEven) {
-  test_full_range(NEG_START, NEG_STOP, NUM_THREADS,
-                  mpfr::RoundingMode::Nearest);
+  test_full_range(NEG_START, NEG_STOP, mpfr::RoundingMode::Nearest);
 }
 
 TEST_F(LlvmLibcExpfExhaustiveTest, NegativeRangeRoundUp) {
-  test_full_range(NEG_START, NEG_STOP, NUM_THREADS, mpfr::RoundingMode::Upward);
+  test_full_range(NEG_START, NEG_STOP, mpfr::RoundingMode::Upward);
 }
 
 TEST_F(LlvmLibcExpfExhaustiveTest, NegativeRangeRoundDown) {
-  test_full_range(NEG_START, NEG_STOP, NUM_THREADS,
-                  mpfr::RoundingMode::Downward);
+  test_full_range(NEG_START, NEG_STOP, mpfr::RoundingMode::Downward);
 }
 
 TEST_F(LlvmLibcExpfExhaustiveTest, NegativeRangeRoundTowardZero) {
-  test_full_range(NEG_START, NEG_STOP, NUM_THREADS,
-                  mpfr::RoundingMode::TowardZero);
+  test_full_range(NEG_START, NEG_STOP, mpfr::RoundingMode::TowardZero);
 }

libc/test/src/math/exhaustive/expm1f_test.cpp

do {
       float x = float(xbits);
       result &= EXPECT_MPFR_MATCH(mpfr::Operation::Expm1, x,
                                   __llvm_libc::expm1f(x), 0.5, rounding);
     } while (bits-- > start);
     return result;
   }
 };
 
-static const int NUM_THREADS = std::thread::hardware_concurrency();
-
 // Range: [0, 89];
 static constexpr uint32_t POS_START = 0x0000'0000U;
 static constexpr uint32_t POS_STOP = 0x42b2'0000U;
 
 TEST_F(LlvmLibcExpm1fExhaustiveTest, PostiveRangeRoundNearestTieToEven) {
-  test_full_range(POS_START, POS_STOP, NUM_THREADS,
-                  mpfr::RoundingMode::Nearest);
+  test_full_range(POS_START, POS_STOP, mpfr::RoundingMode::Nearest);
 }
 
 TEST_F(LlvmLibcExpm1fExhaustiveTest, PostiveRangeRoundUp) {
-  test_full_range(POS_START, POS_STOP, NUM_THREADS, mpfr::RoundingMode::Upward);
+  test_full_range(POS_START, POS_STOP, mpfr::RoundingMode::Upward);
 }
 
 TEST_F(LlvmLibcExpm1fExhaustiveTest, PostiveRangeRoundDown) {
-  test_full_range(POS_START, POS_STOP, NUM_THREADS,
-                  mpfr::RoundingMode::Downward);
+  test_full_range(POS_START, POS_STOP, mpfr::RoundingMode::Downward);
 }
 
 TEST_F(LlvmLibcExpm1fExhaustiveTest, PostiveRangeRoundTowardZero) {
-  test_full_range(POS_START, POS_STOP, NUM_THREADS,
-                  mpfr::RoundingMode::TowardZero);
+  test_full_range(POS_START, POS_STOP, mpfr::RoundingMode::TowardZero);
 }
 
 // Range: [-104, 0];
 static constexpr uint32_t NEG_START = 0x8000'0000U;
 static constexpr uint32_t NEG_STOP = 0xc2d0'0000U;
 
 TEST_F(LlvmLibcExpm1fExhaustiveTest, NegativeRangeRoundNearestTieToEven) {
-  test_full_range(NEG_START, NEG_STOP, NUM_THREADS,
-                  mpfr::RoundingMode::Nearest);
+  test_full_range(NEG_START, NEG_STOP, mpfr::RoundingMode::Nearest);
 }
 
 TEST_F(LlvmLibcExpm1fExhaustiveTest, NegativeRangeRoundUp) {
-  test_full_range(NEG_START, NEG_STOP, NUM_THREADS, mpfr::RoundingMode::Upward);
+  test_full_range(NEG_START, NEG_STOP, mpfr::RoundingMode::Upward);
 }
 
 TEST_F(LlvmLibcExpm1fExhaustiveTest, NegativeRangeRoundDown) {
-  test_full_range(NEG_START, NEG_STOP, NUM_THREADS,
-                  mpfr::RoundingMode::Downward);
+  test_full_range(NEG_START, NEG_STOP, mpfr::RoundingMode::Downward);
 }
 
 TEST_F(LlvmLibcExpm1fExhaustiveTest, NegativeRangeRoundTowardZero) {
-  test_full_range(NEG_START, NEG_STOP, NUM_THREADS,
-                  mpfr::RoundingMode::TowardZero);
+  test_full_range(NEG_START, NEG_STOP, mpfr::RoundingMode::TowardZero);
 }

libc/test/src/math/exhaustive/hypotf_test.cpp

bool check(uint32_t start, uint32_t stop,
     } while (xbits++ < stop);
     return result;
   }
 };
 
 // Range of the first input: [2^23, 2^24);
 static constexpr uint32_t START = (23U + 127U) << 23;
 static constexpr uint32_t STOP = ((23U + 127U) << 23) + 1;
-static constexpr int NUM_THREADS = 1;
 
 TEST_F(LlvmLibcHypotfExhaustiveTest, RoundNearestTieToEven) {
-  test_full_range(START, STOP, NUM_THREADS, mpfr::RoundingMode::Nearest);
+  test_full_range(START, STOP, mpfr::RoundingMode::Nearest);
 }
 
 TEST_F(LlvmLibcHypotfExhaustiveTest, RoundUp) {
-  test_full_range(START, STOP, NUM_THREADS, mpfr::RoundingMode::Upward);
+  test_full_range(START, STOP, mpfr::RoundingMode::Upward);
 }
 
 TEST_F(LlvmLibcHypotfExhaustiveTest, RoundDown) {
-  test_full_range(START, STOP, NUM_THREADS, mpfr::RoundingMode::Downward);
+  test_full_range(START, STOP, mpfr::RoundingMode::Downward);
 }
 
 TEST_F(LlvmLibcHypotfExhaustiveTest, RoundTowardZero) {
-  test_full_range(START, STOP, NUM_THREADS, mpfr::RoundingMode::TowardZero);
+  test_full_range(START, STOP, mpfr::RoundingMode::TowardZero);
 }

libc/test/src/math/exhaustive/log10f_test.cpp

 };
 
 // Range: All non-negative;
 static constexpr uint32_t START = 0x0000'0000U;
 static constexpr uint32_t STOP = 0x7f80'0000U;
 // Range: [1, 10];
 // static constexpr uint32_t START = 0x3f80'0000U;
 // static constexpr uint32_t STOP  = 0x41c0'0000U;
-static constexpr int NUM_THREADS = 16;
-
 TEST_F(LlvmLibcLog10fExhaustiveTest, RoundNearestTieToEven) {
-  test_full_range(START, STOP, NUM_THREADS, mpfr::RoundingMode::Nearest);
+  test_full_range(START, STOP, mpfr::RoundingMode::Nearest);
 }
 
 TEST_F(LlvmLibcLog10fExhaustiveTest, RoundUp) {
-  test_full_range(START, STOP, NUM_THREADS, mpfr::RoundingMode::Upward);
+  test_full_range(START, STOP, mpfr::RoundingMode::Upward);
 }
 
 TEST_F(LlvmLibcLog10fExhaustiveTest, RoundDown) {
-  test_full_range(START, STOP, NUM_THREADS, mpfr::RoundingMode::Downward);
+  test_full_range(START, STOP, mpfr::RoundingMode::Downward);
 }
 
 TEST_F(LlvmLibcLog10fExhaustiveTest, RoundTowardZero) {
-  test_full_range(START, STOP, NUM_THREADS, mpfr::RoundingMode::TowardZero);
+  test_full_range(START, STOP, mpfr::RoundingMode::TowardZero);
 }

libc/test/src/math/exhaustive/log1pf_test.cpp

 };
 
 // Range: All non-negative;
 static constexpr uint32_t START = 0x0000'0000U;
 static constexpr uint32_t STOP = 0x7f80'0000U;
 // Range: [-1, 0];
 // static constexpr uint32_t START = 0x8000'0000U;
 // static constexpr uint32_t STOP  = 0xbf80'0000U;
-static constexpr int NUM_THREADS = 16;
 
 TEST_F(LlvmLibclog1pfExhaustiveTest, RoundNearestTieToEven) {
-  test_full_range(START, STOP, NUM_THREADS, mpfr::RoundingMode::Nearest);
+  test_full_range(START, STOP, mpfr::RoundingMode::Nearest);
 }
 
 TEST_F(LlvmLibclog1pfExhaustiveTest, RoundUp) {
-  test_full_range(START, STOP, NUM_THREADS, mpfr::RoundingMode::Upward);
+  test_full_range(START, STOP, mpfr::RoundingMode::Upward);
 }
 
 TEST_F(LlvmLibclog1pfExhaustiveTest, RoundDown) {
-  test_full_range(START, STOP, NUM_THREADS, mpfr::RoundingMode::Downward);
+  test_full_range(START, STOP, mpfr::RoundingMode::Downward);
 }
 
 TEST_F(LlvmLibclog1pfExhaustiveTest, RoundTowardZero) {
-  test_full_range(START, STOP, NUM_THREADS, mpfr::RoundingMode::TowardZero);
+  test_full_range(START, STOP, mpfr::RoundingMode::TowardZero);
 }

libc/test/src/math/exhaustive/log2f_test.cpp

do {
       result &= EXPECT_MPFR_MATCH(mpfr::Operation::Log2, x,
                                   __llvm_libc::log2f(x), 0.5, rounding);
     } while (bits++ < stop);
     return result;
   }
 };
 
 TEST_F(LlvmLibcLog2fExhaustiveTest, RoundNearestTieToEven) {
-  test_full_range(/*start=*/0U, /*stop=*/0x7f80'0000U, /*nthreads=*/16,
+  test_full_range(/*start=*/0U, /*stop=*/0x7f80'0000U,
                   mpfr::RoundingMode::Nearest);
 }
 
 TEST_F(LlvmLibcLog2fExhaustiveTest, RoundUp) {
-  test_full_range(/*start=*/0U, /*stop=*/0x7f80'0000U, /*nthreads=*/16,
+  test_full_range(/*start=*/0U, /*stop=*/0x7f80'0000U,
                   mpfr::RoundingMode::Upward);
 }
 
 TEST_F(LlvmLibcLog2fExhaustiveTest, RoundDown) {
-  test_full_range(/*start=*/0U, /*stop=*/0x7f80'0000U, /*nthreads=*/16,
+  test_full_range(/*start=*/0U, /*stop=*/0x7f80'0000U,
                   mpfr::RoundingMode::Downward);
 }
 
 TEST_F(LlvmLibcLog2fExhaustiveTest, RoundTowardZero) {
-  test_full_range(/*start=*/0U, /*stop=*/0x7f80'0000U, /*nthreads=*/16,
+  test_full_range(/*start=*/0U, /*stop=*/0x7f80'0000U,
                   mpfr::RoundingMode::TowardZero);
 }

libc/test/src/math/exhaustive/logf_test.cpp

do {
       result &= EXPECT_MPFR_MATCH(mpfr::Operation::Log, x, __llvm_libc::logf(x),
                                   0.5, rounding);
     } while (bits++ < stop);
     return result;
   }
 };
 
 TEST_F(LlvmLibcLogfExhaustiveTest, RoundNearestTieToEven) {
-  test_full_range(/*start=*/0U, /*stop=*/0x7f80'0000U, /*nthreads=*/16,
+  test_full_range(/*start=*/0U, /*stop=*/0x7f80'0000U,
                   mpfr::RoundingMode::Nearest);
 }
 
 TEST_F(LlvmLibcLogfExhaustiveTest, RoundUp) {
-  test_full_range(/*start=*/0U, /*stop=*/0x7f80'0000U, /*nthreads=*/16,
+  test_full_range(/*start=*/0U, /*stop=*/0x7f80'0000U,
                   mpfr::RoundingMode::Upward);
 }
 
 TEST_F(LlvmLibcLogfExhaustiveTest, RoundDown) {
-  test_full_range(/*start=*/0U, /*stop=*/0x7f80'0000U, /*nthreads=*/16,
+  test_full_range(/*start=*/0U, /*stop=*/0x7f80'0000U,
                   mpfr::RoundingMode::Downward);
 }
 
 TEST_F(LlvmLibcLogfExhaustiveTest, RoundTowardZero) {
-  test_full_range(/*start=*/0U, /*stop=*/0x7f80'0000U, /*nthreads=*/16,
+  test_full_range(/*start=*/0U, /*stop=*/0x7f80'0000U,
                   mpfr::RoundingMode::TowardZero);
 }