[Patch, libfortran] PR 47571 Some janitorial cleanup

[Janne Blomqvist]

On Sat, Feb 5, 2011 at 17:58, Jerry DeLisle <jvdelisle@frontier.com> wrote:
> On 02/03/2011 04:45 AM, Janne Blomqvist wrote:
>>
>> On Wed, Feb 2, 2011 at 21:23, Janne Blomqvist<blomqvist.janne@gmail.com>
>>  wrote:
>>>
>>> Hi,
>>>
>>> I reviewed the Gfortran time intrinsics, both standard and extensions,
>>> and AFAIK the only place where a monotonic clock fits the API, and
>>> where we can expose high resolution, is the SYSTEM_CLOCK intrinsic.
>>>
>>> Now, due to the PR 47571 fix where we now call clock_gettime() via a
>>> weakref, some of the original reason behind the gf_gettime() wrapper
>>> has been lost, as now we still need to include fallback code in case
>>> the weakref is not available. This needlessly bloats the code for
>>> date_and_time() which is unable to use either the extra precision and
>>> needs a realtime clock, not a monotonic clock. Additionally, in some
>>> not quite bleeding edge Linux kernels, gettimeofday() is a vsyscall
>>> and clock_gettime() isn't, leading to higher overhead for no benefit
>>> (the difference is something like 1e6 vs 1e7 calls/s on current hw, so
>>> it's exceedingly unlikely to actually matter in reality).  The only
>>> fly in the ointment here is that POSIX 2008 has marked gettimeofday()
>>> as obsolescent, however I don't see this mattering in reality for the
>>> foreseeable future.
>>>
>>> The attached patch moves all the weakref trickery and clock_gettime()
>>> usage from time_1.h to system_clock.c, where the only benefactor also
>>> lives.
>>
>> Hi,
>>
>> updated patch attached. Compared to the previous one this might fix
>> the build regression reported on HP-UX which does support weak symbols
>> but apparently does barf on weak undefined references. This is done in
>> a slightly kludgy way, in that in acinclude.m4 we previously have set
>> GTHREAD_USE_WEAK to 0 for such targets, hence in the updated patch
>> GTHREAD_USE_WEAK is defined and set to 1 if it's not previously
>> present, and then we check for both SUPPORTS_WEAK and
>> GTHREAD_USE_WEAK.
>>
>> 2011-02-03  Janne Blomqvist<jb@gcc.gnu.org>
>>
>>        PR libfortran/47571
>>        * intrinsics/time_1.h (GF_CLOCK_MONOTONIC): Move to system_clock.c.
>>        (weak_gettime): Likewise.
>>        (gf_gettime): Change API, move weak_gettime() usage to
>>        system_clock.c
>>        * intrinsics/system_clock.c (GTHREAD_USE_WEAK): Define.
>>        (gf_gettime_mono): New function.
>>        (system_clock_4): Use gf_gettime_mono().
>>        (system_clock_8): Likewise.
>>        * intrinsics/date_and_time.c (date_and_time): Update gf_gettime()
>>        usage.
>>
>> Regtested on x86_64-unknown-linux-gnu, Ok for trunk?
>>
>
> OK and thanks for patch.
>
> Jerry
>

Thanks,

Sending        libgfortran/ChangeLog
Sending        libgfortran/intrinsics/date_and_time.c
Sending        libgfortran/intrinsics/system_clock.c
Sending        libgfortran/intrinsics/time_1.h
Transmitting file data ....
Committed revision 169852.


-- 
Janne Blomqvist