RE: [PATCH v7] libgfortran: Replace mutex with rwlock

[Thomas Schwinge <thomas@codesourcery.com>]

Hi Lipeng!

On 2023-12-14T02:28:22+0000, "Zhu, Lipeng" <lipeng.zhu@intel.com> wrote:
> On 2023/12/14 4:52, Thomas Schwinge wrote:
>> On 2023-12-12T02:05:26+0000, "Zhu, Lipeng" <lipeng.zhu@intel.com> wrote:
>> > On 2023/12/12 1:45, H.J. Lu wrote:
>> >> On Sat, Dec 9, 2023 at 7:25 PM Zhu, Lipeng <lipeng.zhu@intel.com>
>> wrote:
>> >> > On 2023/12/9 23:23, Jakub Jelinek wrote:
>> >> > > On Sat, Dec 09, 2023 at 10:39:45AM -0500, Lipeng Zhu wrote:
>> >> > > > This patch try to introduce the rwlock and split the read/write
>> >> > > > to unit_root tree and unit_cache with rwlock instead of the
>> >> > > > mutex to increase CPU efficiency. In the get_gfc_unit function,
>> >> > > > the percentage to step into the insert_unit function is around
>> >> > > > 30%, in most instances, we can get the unit in the phase of
>> >> > > > reading the unit_cache or unit_root tree. So split the
>> >> > > > read/write phase by rwlock would be an approach to make it more
>> parallel.
>> >> > > >
>> >> > > > BTW, the IPC metrics can gain around 9x in our test server with
>> >> > > > 220 cores. The benchmark we used is
>> >> > > > https://github.com/rwesson/NEAT

>> I've just filed <https://gcc.gnu.org/PR113005>
>> "'libgomp.fortran/rwlock_1.f90', 'libgomp.fortran/rwlock_3.f90' execution
>> test timeouts".
>> Would you be able to look into that?

> Sure, I will look into that.
>
> BTW, I didn’t have the PowerPC in hands, do you mind granting the access of your
> test environment to me to help reproduce the issue?

That's unfortunately not possible: it's behind company VPN, restricted
access.  :-/ I'll later try to have at least a quick look where it's
hanging, or what it's doing.


Grüße
 Thomas
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