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

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

[Alexandre Oliva]

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>

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

[Alexandre Oliva]

On Jun 22, 2022, Alexandre Oliva <oliva@adacore.com> wrote:

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

The early wakeups are fixed for rtems6.1, so the same question raised at
https://gcc.gnu.org/pipermail/gcc-patches/2022-June/597102.html apply to
this one:

libstdc++: xfail nanosleep tests on rtems

From: Alexandre Oliva <oliva@adacore.com>

Since it has been determined that nanosleep may return slightly too
early on RTEMS, due to clock resolution differences, expect
30_thread/async tests that have detected too-early wakeups to fail on
RTEMS targets.


for  libstdc++-v3/ChangeLog

	* testsuite/30_threads/async/async.cc: xfail on RTEMS.

TN: V608-048
---
 libstdc++-v3/testsuite/30_threads/async/async.cc |    1 +
 1 file changed, 1 insertion(+)

diff --git a/libstdc++-v3/testsuite/30_threads/async/async.cc b/libstdc++-v3/testsuite/30_threads/async/async.cc
index 38943ff1a9a5e..e0b731186c459 100644
--- a/libstdc++-v3/testsuite/30_threads/async/async.cc
+++ b/libstdc++-v3/testsuite/30_threads/async/async.cc
@@ -2,6 +2,7 @@
 // { dg-additional-options "-pthread" { target pthread } }
 // { dg-require-effective-target c++11 }
 // { dg-require-gthreads "" }
+// { dg-xfail-if "nanosleep may wake up too early" { *-*-rtems* } }
 
 // Copyright (C) 2010-2022 Free Software Foundation, Inc.
 //


-- 
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>

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

[Jonathan Wakely]

On Thu, 23 Jun 2022 at 12:38, Alexandre Oliva via Libstdc++
<libstdc++@gcc.gnu.org> wrote:
>
> On Jun 22, 2022, Alexandre Oliva <oliva@adacore.com> wrote:
>
> > Regstrapped on x86_64-linux-gnu, also tested with a cross to
> > aarch64-rtems6.  Ok to install?
>
> The early wakeups are fixed for rtems6.1, so the same question raised at
> https://gcc.gnu.org/pipermail/gcc-patches/2022-June/597102.html apply to
> this one:

Looks like I never reviewed this one, sorry.

The patch to xfail this test for rtems is OK.

>
> libstdc++: xfail nanosleep tests on rtems
>
> From: Alexandre Oliva <oliva@adacore.com>
>
> Since it has been determined that nanosleep may return slightly too
> early on RTEMS, due to clock resolution differences, expect
> 30_thread/async tests that have detected too-early wakeups to fail on
> RTEMS targets.
>
>
> for  libstdc++-v3/ChangeLog
>
>         * testsuite/30_threads/async/async.cc: xfail on RTEMS.
>
> TN: V608-048
> ---
>  libstdc++-v3/testsuite/30_threads/async/async.cc |    1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/libstdc++-v3/testsuite/30_threads/async/async.cc b/libstdc++-v3/testsuite/30_threads/async/async.cc
> index 38943ff1a9a5e..e0b731186c459 100644
> --- a/libstdc++-v3/testsuite/30_threads/async/async.cc
> +++ b/libstdc++-v3/testsuite/30_threads/async/async.cc
> @@ -2,6 +2,7 @@
>  // { dg-additional-options "-pthread" { target pthread } }
>  // { dg-require-effective-target c++11 }
>  // { dg-require-gthreads "" }
> +// { dg-xfail-if "nanosleep may wake up too early" { *-*-rtems* } }
>
>  // Copyright (C) 2010-2022 Free Software Foundation, Inc.
>  //
>
>
> --
> 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>
>

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

[Jonathan Wakely]

On Wed, 12 Oct 2022 at 12:41, Jonathan Wakely wrote:
>
> On Thu, 23 Jun 2022 at 12:38, Alexandre Oliva via Libstdc++
> <libstdc++@gcc.gnu.org> wrote:
> >
> > On Jun 22, 2022, Alexandre Oliva <oliva@adacore.com> wrote:
> >
> > > Regstrapped on x86_64-linux-gnu, also tested with a cross to
> > > aarch64-rtems6.  Ok to install?
> >
> > The early wakeups are fixed for rtems6.1, so the same question raised at
> > https://gcc.gnu.org/pipermail/gcc-patches/2022-June/597102.html apply to
> > this one:
>
> Looks like I never reviewed this one, sorry.
>
> The patch to xfail this test for rtems is OK.

It's also fine if you just want to drop this patch for the same reason
as https://gcc.gnu.org/pipermail/gcc-patches/2022-June/597105.html

(I'm just going through old patch submissions that never got acked or
nacked and this was one of them.)

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

[Alexandre Oliva]

On Oct 12, 2022, Jonathan Wakely <jwakely@redhat.com> wrote:

> On Wed, 12 Oct 2022 at 12:41, Jonathan Wakely wrote:
>> 
>> On Thu, 23 Jun 2022 at 12:38, Alexandre Oliva via Libstdc++
>> <libstdc++@gcc.gnu.org> wrote:
>> >
>> > On Jun 22, 2022, Alexandre Oliva <oliva@adacore.com> wrote:
>> >
>> > > Regstrapped on x86_64-linux-gnu, also tested with a cross to
>> > > aarch64-rtems6.  Ok to install?
>> >
>> > The early wakeups are fixed for rtems6.1, so the same question raised at
>> > https://gcc.gnu.org/pipermail/gcc-patches/2022-June/597102.html apply to
>> > this one:
>> 
>> Looks like I never reviewed this one, sorry.
>> 
>> The patch to xfail this test for rtems is OK.

> It's also fine if you just want to drop this patch for the same reason
> as https://gcc.gnu.org/pipermail/gcc-patches/2022-June/597105.html

Yeah, nanosleep is fixed, no need for this one, thanks, withdrawn.

-- 
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>