[Lldb-commits] [lldb] r326514 - Speed up TestWatchpointMultipleThreads

Pavel Labath via lldb-commits lldb-commits at lists.llvm.org
Thu Mar 1 16:17:05 PST 2018


Author: labath
Date: Thu Mar  1 16:17:05 2018
New Revision: 326514

URL: http://llvm.org/viewvc/llvm-project?rev=326514&view=rev
Log:
Speed up TestWatchpointMultipleThreads

Summary:
The inferior was sleeping before doing any interesting work. I remove that
to make the test faster.

While looking at the purpose of the test (to check that watchpoints are
propagated to all existing threads - r140757) I noticed that the test has
diverged from the original intention and now it creates the threads *after* the
watchpoint is set (this probably happened during the std::thread refactor).
After some discussion, we decided both scenarios make sense, so I modify the
test to test both.

The watchpoint propagation functionality is not really debug info depenent, so
I also stop replication of this test. This brings the test's time from ~108s
down to 4s.

Reviewers: davide, jingham

Subscribers: aprantl, lldb-commits

Differential Revision: https://reviews.llvm.org/D43857

Modified:
    lldb/trunk/packages/Python/lldbsuite/test/functionalities/watchpoint/multiple_threads/TestWatchpointMultipleThreads.py
    lldb/trunk/packages/Python/lldbsuite/test/functionalities/watchpoint/multiple_threads/main.cpp

Modified: lldb/trunk/packages/Python/lldbsuite/test/functionalities/watchpoint/multiple_threads/TestWatchpointMultipleThreads.py
URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/packages/Python/lldbsuite/test/functionalities/watchpoint/multiple_threads/TestWatchpointMultipleThreads.py?rev=326514&r1=326513&r2=326514&view=diff
==============================================================================
--- lldb/trunk/packages/Python/lldbsuite/test/functionalities/watchpoint/multiple_threads/TestWatchpointMultipleThreads.py (original)
+++ lldb/trunk/packages/Python/lldbsuite/test/functionalities/watchpoint/multiple_threads/TestWatchpointMultipleThreads.py Thu Mar  1 16:17:05 2018
@@ -17,51 +17,26 @@ from lldbsuite.test import lldbutil
 class WatchpointForMultipleThreadsTestCase(TestBase):
 
     mydir = TestBase.compute_mydir(__file__)
+    NO_DEBUG_INFO_TESTCASE = True
+    main_spec = lldb.SBFileSpec("main.cpp", False)
 
     @expectedFailureAll(
         oslist=["windows"],
         bugnumber="llvm.org/pr24446: WINDOWS XFAIL TRIAGE - Watchpoints not supported on Windows")
-    def test_watchpoint_multiple_threads(self):
-        """Test that lldb watchpoint works for multiple threads."""
-        self.build()
-        self.setTearDownCleanup()
-        self.hello_multiple_threads()
+    def test_watchpoint_before_thread_start(self):
+        """Test that we can hit a watchpoint we set before starting another thread"""
+        self.do_watchpoint_test("Before running the thread")
 
     @expectedFailureAll(
         oslist=["windows"],
         bugnumber="llvm.org/pr24446: WINDOWS XFAIL TRIAGE - Watchpoints not supported on Windows")
-    def test_watchpoint_multiple_threads_wp_set_and_then_delete(self):
-        """Test that lldb watchpoint works for multiple threads, and after the watchpoint is deleted, the watchpoint event should no longer fires."""
-        self.build()
-        self.setTearDownCleanup()
-        self.hello_multiple_threads_wp_set_and_then_delete()
+    def test_watchpoint_after_thread_start(self):
+        """Test that we can hit a watchpoint we set after starting another thread"""
+        self.do_watchpoint_test("After running the thread")
 
-    def setUp(self):
-        # Call super's setUp().
-        TestBase.setUp(self)
-        # Our simple source filename.
-        self.source = 'main.cpp'
-        # Find the line number to break inside main().
-        self.first_stop = line_number(
-            self.source, '// Set break point at this line')
-
-    def hello_multiple_threads(self):
-        """Test that lldb watchpoint works for multiple threads."""
-        self.runCmd("file " + self.getBuildArtifact("a.out"),
-                    CURRENT_EXECUTABLE_SET)
-
-        # Add a breakpoint to set a watchpoint when stopped on the breakpoint.
-        lldbutil.run_break_set_by_file_and_line(
-            self, None, self.first_stop, num_expected_locations=1)
-
-        # Run the program.
-        self.runCmd("run", RUN_SUCCEEDED)
-
-        # We should be stopped again due to the breakpoint.
-        # The stop reason of the thread should be breakpoint.
-        self.expect("thread list", STOPPED_DUE_TO_BREAKPOINT,
-                    substrs=['stopped',
-                             'stop reason = breakpoint'])
+    def do_watchpoint_test(self, line):
+        self.build()
+        lldbutil.run_to_source_breakpoint(self, line, self.main_spec)
 
         # Now let's set a write-type watchpoint for variable 'g_val'.
         self.expect(
@@ -77,39 +52,29 @@ class WatchpointForMultipleThreadsTestCa
         self.expect("watchpoint list -v",
                     substrs=['hit_count = 0'])
 
-        while True:
-            self.runCmd("process continue")
+        self.runCmd("process continue")
 
-            self.runCmd("thread list")
-            if "stop reason = watchpoint" in self.res.GetOutput():
-                # Good, we verified that the watchpoint works!
-                self.runCmd("thread backtrace all")
-                break
-            else:
-                self.fail("The stop reason should be either break or watchpoint")
+        self.runCmd("thread list")
+        if "stop reason = watchpoint" in self.res.GetOutput():
+            # Good, we verified that the watchpoint works!
+            self.runCmd("thread backtrace all")
+        else:
+            self.fail("The stop reason should be either break or watchpoint")
 
         # Use the '-v' option to do verbose listing of the watchpoint.
         # The hit count should now be 1.
         self.expect("watchpoint list -v",
                     substrs=['hit_count = 1'])
 
-    def hello_multiple_threads_wp_set_and_then_delete(self):
+    @expectedFailureAll(
+        oslist=["windows"],
+        bugnumber="llvm.org/pr24446: WINDOWS XFAIL TRIAGE - Watchpoints not supported on Windows")
+    def test_watchpoint_multiple_threads_wp_set_and_then_delete(self):
         """Test that lldb watchpoint works for multiple threads, and after the watchpoint is deleted, the watchpoint event should no longer fires."""
-        self.runCmd("file " + self.getBuildArtifact("a.out"),
-                    CURRENT_EXECUTABLE_SET)
+        self.build()
+        self.setTearDownCleanup()
 
-        # Add a breakpoint to set a watchpoint when stopped on the breakpoint.
-        lldbutil.run_break_set_by_file_and_line(
-            self, None, self.first_stop, num_expected_locations=1)
-
-        # Run the program.
-        self.runCmd("run", RUN_SUCCEEDED)
-
-        # We should be stopped again due to the breakpoint.
-        # The stop reason of the thread should be breakpoint.
-        self.expect("thread list", STOPPED_DUE_TO_BREAKPOINT,
-                    substrs=['stopped',
-                             'stop reason = breakpoint'])
+        lldbutil.run_to_source_breakpoint(self, "After running the thread", self.main_spec)
 
         # Now let's set a write-type watchpoint for variable 'g_val'.
         self.expect(

Modified: lldb/trunk/packages/Python/lldbsuite/test/functionalities/watchpoint/multiple_threads/main.cpp
URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/packages/Python/lldbsuite/test/functionalities/watchpoint/multiple_threads/main.cpp?rev=326514&r1=326513&r2=326514&view=diff
==============================================================================
--- lldb/trunk/packages/Python/lldbsuite/test/functionalities/watchpoint/multiple_threads/main.cpp (original)
+++ lldb/trunk/packages/Python/lldbsuite/test/functionalities/watchpoint/multiple_threads/main.cpp Thu Mar  1 16:17:05 2018
@@ -7,73 +7,29 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include <chrono>
+#include "pseudo_barrier.h"
 #include <cstdio>
-#include <mutex>
-#include <random>
 #include <thread>
 
-std::default_random_engine g_random_engine{std::random_device{}()};
-std::uniform_int_distribution<> g_distribution{0, 3000000};
+volatile uint32_t g_val = 0;
+pseudo_barrier_t g_barrier;
 
-uint32_t g_val = 0;
-
-
-uint32_t
-access_pool (bool flag = false)
-{
-    static std::mutex g_access_mutex;
-    g_access_mutex.lock();
-
-    uint32_t old_val = g_val;
-    if (flag)
-    {
-        printf("changing g_val to %d...\n", old_val + 1);
-        g_val = old_val + 1;
-    }
-
-    g_access_mutex.unlock();
-    return g_val;
+void thread_func() {
+  pseudo_barrier_wait(g_barrier);
+  printf("%s starting...\n", __FUNCTION__);
+  for (uint32_t i = 0; i < 10; ++i)
+    g_val = i;
 }
 
-void
-thread_func (uint32_t thread_index)
-{
-    printf ("%s (thread index = %u) starting...\n", __FUNCTION__, thread_index);
-
-    uint32_t count = 0;
-    uint32_t val;
-    while (count++ < 15)
-    {
-        // random micro second sleep from zero to 3 seconds
-        int usec = g_distribution(g_random_engine);
-        printf ("%s (thread = %u) doing a usleep (%d)...\n", __FUNCTION__, thread_index, usec);
-        std::this_thread::sleep_for(std::chrono::microseconds{usec});
-
-        if (count < 7)
-            val = access_pool ();
-        else
-            val = access_pool (true);
-
-        printf ("%s (thread = %u) after usleep access_pool returns %d (count=%d)...\n", __FUNCTION__, thread_index, val, count);
-    }
-    printf ("%s (thread index = %u) exiting...\n", __FUNCTION__, thread_index);
-}
+int main(int argc, char const *argv[]) {
+  printf("Before running the thread\n");
+  pseudo_barrier_init(g_barrier, 2);
+  std::thread thread(thread_func);
 
+  printf("After running the thread\n");
+  pseudo_barrier_wait(g_barrier);
 
-int main (int argc, char const *argv[])
-{
-    std::thread threads[3];
-
-    printf ("Before turning all three threads loose...\n"); // Set break point at this line,
-                                                            // in order to set our watchpoint.
-    // Create 3 threads
-    for (auto &thread : threads)
-        thread = std::thread{thread_func, std::distance(threads, &thread)};
-
-    // Join all of our threads
-    for (auto &thread : threads)
-        thread.join();
+  thread.join();
 
-    return 0;
+  return 0;
 }




More information about the lldb-commits mailing list