[PATCH] libstdc++: async: tolerate slightly shorter sleep

[Alexandre Oliva <oliva@adacore.com>]

Even without frequent signals interrupting nanosleep, sleep_for on
rtems on qemu wakes up too early by a predictable margin of less than
0,3%, which some async tests complain about the too-short wait times.
Allow the tests to tolerate a little sleep deprivation.

Regstrapped on x86_64-linux-gnu, also tested with a cross to
aarch64-rtems6.  Ok to install?


for  libstdc++-v3/ChangeLog

	* testsuite/30_threads/async/async.cc: Tolerate early wakeup.
---
 libstdc++-v3/testsuite/30_threads/async/async.cc |    9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/libstdc++-v3/testsuite/30_threads/async/async.cc b/libstdc++-v3/testsuite/30_threads/async/async.cc
index 38943ff1a9a5e..b151677af6a0e 100644
--- a/libstdc++-v3/testsuite/30_threads/async/async.cc
+++ b/libstdc++-v3/testsuite/30_threads/async/async.cc
@@ -104,7 +104,8 @@ void test03()
   VERIFY( status == std::future_status::ready );
 
   auto const elapsed = CLOCK::now() - start;
-  VERIFY( elapsed >= std::chrono::seconds(2) );
+  auto const tolerance = std::chrono::milliseconds(6);
+  VERIFY( elapsed + tolerance >= std::chrono::seconds(2) );
   VERIFY( elapsed < std::chrono::seconds(5) );
 }
 
@@ -169,7 +170,8 @@ void test_pr91486_wait_for()
   auto status = f1.wait_for(wait_time);
   auto const elapsed_steady = chrono::steady_clock::now() - start_steady;
 
-  VERIFY( elapsed_steady >= std::chrono::seconds(1) );
+  auto const tolerance = std::chrono::milliseconds(3);
+  VERIFY( elapsed_steady + tolerance >= std::chrono::seconds(1) );
 }
 
 // This is a clock with a very recent epoch which ensures that the difference
@@ -222,7 +224,8 @@ void test_pr91486_wait_until()
   auto const elapsed_steady = chrono::steady_clock::now() - start_steady;
 
   // This checks that we didn't come back too soon
-  VERIFY( elapsed_steady >= std::chrono::seconds(1) );
+  auto const tolerance = std::chrono::milliseconds(3);
+  VERIFY( elapsed_steady + tolerance >= std::chrono::seconds(1) );
 
   // This checks that wait_until didn't busy wait checking the clock more times
   // than necessary.


-- 
Alexandre Oliva, happy hacker                https://FSFLA.org/blogs/lxo/
   Free Software Activist                       GNU Toolchain Engineer
Disinformation flourishes because many people care deeply about injustice
but very few check the facts.  Ask me about <https://stallmansupport.org>