[libcxx] r291331 - thread: implement sleep_for on Windows

[Asiri Rathnayake via cfe-commits]

Yup, that sounds better.

I'll put up a patch soon.

Cheers,

/ Asiri

On 7 Jan 2017 9:18 p.m., "Saleem Abdulrasool" <compnerd at compnerd.org> wrote:

> I would really rather not introduce a `__libcpp_thread_nanosleep`.
> Different systems may have different granularities for their sleep.  A
> `__libcpp_sleep_for(std::chrono::duration)` sounds reasonable however.
>
> On Fri, Jan 6, 2017 at 11:53 PM, Asiri Rathnayake <
> asiri.rathnayake at gmail.com> wrote:
>
>> Wouldn't it be better to introduce a __libcpp_thread_nanosleep() API call
>> here?
>>
>> I bumped into a similar issue with a custom thread implementation and
>> have a downstream patch like that.
>>
>> Cheers,
>>
>> / Asiri
>>
>>
>> On 7 Jan 2017 2:59 a.m., "Saleem Abdulrasool via cfe-commits" <
>> cfe-commits at lists.llvm.org> wrote:
>>
>> Author: compnerd
>> Date: Fri Jan  6 20:48:30 2017
>> New Revision: 291331
>>
>> URL: http://llvm.org/viewvc/llvm-project?rev=291331&view=rev
>> Log:
>> thread: implement sleep_for on Windows
>>
>> Windows does not provide an implementation of `nanosleep`.  Round up the
>> time duration to the nearest ms and use `Sleep`.  Although this may
>> over-sleep, there is no hard real-time guarantee on the wake, so
>> sleeping a bit more is better than under-sleeping as it within the
>> specification.
>>
>> Modified:
>>     libcxx/trunk/src/thread.cpp
>>
>> Modified: libcxx/trunk/src/thread.cpp
>> URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/src/thread.
>> cpp?rev=291331&r1=291330&r2=291331&view=diff
>> ============================================================
>> ==================
>> --- libcxx/trunk/src/thread.cpp (original)
>> +++ libcxx/trunk/src/thread.cpp Fri Jan  6 20:48:30 2017
>> @@ -117,6 +117,12 @@ sleep_for(const chrono::nanoseconds& ns)
>>      using namespace chrono;
>>      if (ns > nanoseconds::zero())
>>      {
>> +#if defined(_LIBCPP_WIN32API)
>> +        milliseconds ms = duration_cast<milliseconds>(ns);
>> +        if (ns > duration_cast<nanoseconds>(ms))
>> +          ++ms;
>> +        Sleep(ms.count());
>> +#else
>>          seconds s = duration_cast<seconds>(ns);
>>          timespec ts;
>>          typedef decltype(ts.tv_sec) ts_sec;
>> @@ -134,6 +140,7 @@ sleep_for(const chrono::nanoseconds& ns)
>>
>>          while (nanosleep(&ts, &ts) == -1 && errno == EINTR)
>>              ;
>> +#endif
>>      }
>>  }
>>
>>
>>
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>>
>>
>>
>
>
> --
> Saleem Abdulrasool
> compnerd (at) compnerd (dot) org
>
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