On 27/12/22 08:33 -0800, H.J. Lu wrote:
On Sun, Dec 25, 2022 at 4:58 PM Steve Kargl via Gcc-patches
<gcc-patc...@gcc.gnu.org> wrote:
On Wed, Dec 21, 2022 at 07:27:11PM -0500, Lipeng Zhu via Fortran 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 increase from 0.25 to 2.2 in the Intel
> SRP server with 220 cores. The benchmark we used is
> https://github.com/rwesson/NEAT
>
The patch fails bootstrap on x86_64-*-freebsd.
gmake[6]: Entering directory
'/home/kargl/gcc/obj/x86_64-unknown-freebsd14.0/libstdc++-v3/src/c++17'
/bin/sh ../../libtool --tag CXX --tag disable-shared --mode=compile
/home/kargl/gcc/obj/./gcc/xgcc -shared-libgcc -B/home/kargl/gcc/obj/./gcc
-nostdinc++ -L/home/kargl/gcc/obj/x86_64-unknown-freebsd14.0/libstdc++-v3/src
-L/home/kargl/gcc/obj/x86_64-unknown-freebsd14.0/libstdc++-v3/src/.libs
-L/home/kargl/gcc/obj/x86_64-unknown-freebsd14.0/libstdc++-v3/libsupc++/.libs
-B/home/kargl/work/x86_64-unknown-freebsd14.0/bin/
-B/home/kargl/work/x86_64-unknown-freebsd14.0/lib/ -isystem
/home/kargl/work/x86_64-unknown-freebsd14.0/include -isystem
/home/kargl/work/x86_64-unknown-freebsd14.0/sys-include -fno-checking
-I/home/kargl/gcc/gcc/libstdc++-v3/../libgcc
-I/home/kargl/gcc/obj/x86_64-unknown-freebsd14.0/libstdc++-v3/include/x86_64-unknown-freebsd14.0
-I/home/kargl/gcc/obj/x86_64-unknown-freebsd14.0/libstdc++-v3/include
-I/home/kargl/gcc/gcc/libstdc++-v3/libsupc++ -std=gnu++17 -nostdinc++
-prefer-pic -D_GLIBCXX_SHARED -fno-implicit-templates -Wall -Wextra
-Wwrite-strings -Wcast-qual -Wabi=2 -fdiagnostics-show-location=once
-ffunction-sections -fdata-sections -frandom-seed=floating_from_chars.lo
-fimplicit-templates -g -O2 -c -o floating_from_chars.lo
../../../../../gcc/libstdc++-v3/src/c++17/floating_from_chars.cc
libtool: compile: /home/kargl/gcc/obj/./gcc/xgcc -shared-libgcc
-B/home/kargl/gcc/obj/./gcc -nostdinc++
-L/home/kargl/gcc/obj/x86_64-unknown-freebsd14.0/libstdc++-v3/src
-L/home/kargl/gcc/obj/x86_64-unknown-freebsd14.0/libstdc++-v3/src/.libs
-L/home/kargl/gcc/obj/x86_64-unknown-freebsd14.0/libstdc++-v3/libsupc++/.libs
-B/home/kargl/work/x86_64-unknown-freebsd14.0/bin/
-B/home/kargl/work/x86_64-unknown-freebsd14.0/lib/ -isystem
/home/kargl/work/x86_64-unknown-freebsd14.0/include -isystem
/home/kargl/work/x86_64-unknown-freebsd14.0/sys-include -fno-checking
-I/home/kargl/gcc/gcc/libstdc++-v3/../libgcc
-I/home/kargl/gcc/obj/x86_64-unknown-freebsd14.0/libstdc++-v3/include/x86_64-unknown-freebsd14.0
-I/home/kargl/gcc/obj/x86_64-unknown-freebsd14.0/libstdc++-v3/include
-I/home/kargl/gcc/gcc/libstdc++-v3/libsupc++ -std=gnu++17 -nostdinc++
-D_GLIBCXX_SHARED -fno-implicit-templates -Wall -Wextra -Wwrite-strings
-Wcast-qual -Wabi=2 -fdiagnostics-show-location=once -ffunction-sections
-fdata-sections -frandom-seed=floating_from_chars.lo -fimplicit-templates -g
-O2 -c ../../../../../gcc/libstdc++-v3/src/c++17/floating_from_chars.cc -fPIC
-DPIC -D_GLIBCXX_SHARED -o floating_from_chars.o
In file included from
/home/kargl/gcc/obj/x86_64-unknown-freebsd14.0/libstdc++-v3/include/memory_resource:40,
from
../../../../../gcc/libstdc++-v3/src/c++17/floating_from_chars.cc:37:
/home/kargl/gcc/obj/x86_64-unknown-freebsd14.0/libstdc++-v3/include/shared_mutex:
In function 'int std::__glibcxx_rwlock_rdlock(pthread_rwlock**)':
/home/kargl/gcc/obj/x86_64-unknown-freebsd14.0/libstdc++-v3/include/shared_mutex:80:3:
error: call of overloaded '__gthrw_pthread_rwlock_rdlock(pthread_rwlock**&)'
is ambiguous
80 | _GLIBCXX_GTHRW(rwlock_rdlock)
| ^
In file included from
/home/kargl/gcc/obj/x86_64-unknown-freebsd14.0/libstdc++-v3/include/x86_64-unknown-freebsd14.0/bits/gthr.h:148,
from
/home/kargl/gcc/obj/x86_64-unknown-freebsd14.0/libstdc++-v3/include/bits/std_mutex.h:41,
from
/home/kargl/gcc/obj/x86_64-unknown-freebsd14.0/libstdc++-v3/include/shared_mutex:41:
/home/kargl/gcc/obj/x86_64-unknown-freebsd14.0/libstdc++-v3/include/shared_mutex:80:3:
note: candidate: 'int std::__gthrw_pthread_rwlock_rdlock(pthread_rwlock**)'
80 | _GLIBCXX_GTHRW(rwlock_rdlock)
| ^~~~~~~~~~~~~~
/home/kargl/gcc/obj/x86_64-unknown-freebsd14.0/libstdc++-v3/include/x86_64-unknown-freebsd14.0/bits/gthr-default.h:140:1:
note: candidate: 'int __gthrw_pthread_rwlock_rdlock(pthread_rwlock**)'
140 | __gthrw(pthread_rwlock_rdlock)
| ^~~~~~~
/home/kargl/gcc/obj/x86_64-unknown-freebsd14.0/libstdc++-v3/include/shared_mutex:
In function 'int std::__glibcxx_rwlock_tryrdlock(pthread_rwlock**)':
/home/kargl/gcc/obj/x86_64-unknown-freebsd14.0/libstdc++-v3/include/shared_mutex:81:3:
error: call of overloaded
'__gthrw_pthread_rwlock_tryrdlock(pthread_rwlock**&)' is ambiguous
81 | _GLIBCXX_GTHRW(rwlock_tryrdlock)
| ^
/home/kargl/gcc/obj/x86_64-unknown-freebsd14.0/libstdc++-v3/include/shared_mutex:81:3:
note: candidate: 'int std::__gthrw_pthread_rwlock_tryrdlock(pthread_rwlock**)'
81 | _GLIBCXX_GTHRW(rwlock_tryrdlock)
| ^~~~~~~~~~~~~~
/home/kargl/gcc/obj/x86_64-unknown-freebsd14.0/libstdc++-v3/include/x86_64-unknown-freebsd14.0/bits/gthr-default.h:141:1:
note: candidate: 'int __gthrw_pthread_rwlock_tryrdlock(pthread_rwlock**)'
141 | __gthrw(pthread_rwlock_tryrdlock)
| ^~~~~~~
/home/kargl/gcc/obj/x86_64-unknown-freebsd14.0/libstdc++-v3/include/shared_mutex:
In function 'int std::__glibcxx_rwlock_wrlock(pthread_rwlock**)':
/home/kargl/gcc/obj/x86_64-unknown-freebsd14.0/libstdc++-v3/include/shared_mutex:82:3:
error: call of overloaded '__gthrw_pthread_rwlock_wrlock(pthread_rwlock**&)'
is ambiguous
82 | _GLIBCXX_GTHRW(rwlock_wrlock)
| ^
/home/kargl/gcc/obj/x86_64-unknown-freebsd14.0/libstdc++-v3/include/shared_mutex:82:3:
note: candidate: 'int std::__gthrw_pthread_rwlock_wrlock(pthread_rwlock**)'
82 | _GLIBCXX_GTHRW(rwlock_wrlock)
| ^~~~~~~~~~~~~~
/home/kargl/gcc/obj/x86_64-unknown-freebsd14.0/libstdc++-v3/include/x86_64-unknown-freebsd14.0/bits/gthr-default.h:142:1:
note: candidate: 'int __gthrw_pthread_rwlock_wrlock(pthread_rwlock**)'
142 | __gthrw(pthread_rwlock_wrlock)
| ^~~~~~~
/home/kargl/gcc/obj/x86_64-unknown-freebsd14.0/libstdc++-v3/include/shared_mutex:
In function 'int std::__glibcxx_rwlock_trywrlock(pthread_rwlock**)':
/home/kargl/gcc/obj/x86_64-unknown-freebsd14.0/libstdc++-v3/include/shared_mutex:83:3:
error: call of overloaded
'__gthrw_pthread_rwlock_trywrlock(pthread_rwlock**&)' is ambiguous
83 | _GLIBCXX_GTHRW(rwlock_trywrlock)
| ^
/home/kargl/gcc/obj/x86_64-unknown-freebsd14.0/libstdc++-v3/include/shared_mutex:83:3:
note: candidate: 'int std::__gthrw_pthread_rwlock_trywrlock(pthread_rwlock**)'
83 | _GLIBCXX_GTHRW(rwlock_trywrlock)
| ^~~~~~~~~~~~~~
/home/kargl/gcc/obj/x86_64-unknown-freebsd14.0/libstdc++-v3/include/x86_64-unknown-freebsd14.0/bits/gthr-default.h:143:1:
note: candidate: 'int __gthrw_pthread_rwlock_trywrlock(pthread_rwlock**)'
143 | __gthrw(pthread_rwlock_trywrlock)
| ^~~~~~~
/home/kargl/gcc/obj/x86_64-unknown-freebsd14.0/libstdc++-v3/include/shared_mutex:
In function 'int std::__glibcxx_rwlock_unlock(pthread_rwlock**)':
/home/kargl/gcc/obj/x86_64-unknown-freebsd14.0/libstdc++-v3/include/shared_mutex:84:3:
error: call of overloaded '__gthrw_pthread_rwlock_unlock(pthread_rwlock**&)'
is ambiguous
84 | _GLIBCXX_GTHRW(rwlock_unlock)
| ^
/home/kargl/gcc/obj/x86_64-unknown-freebsd14.0/libstdc++-v3/include/shared_mutex:84:3:
note: candidate: 'int std::__gthrw_pthread_rwlock_unlock(pthread_rwlock**)'
84 | _GLIBCXX_GTHRW(rwlock_unlock)
| ^~~~~~~~~~~~~~
/home/kargl/gcc/obj/x86_64-unknown-freebsd14.0/libstdc++-v3/include/x86_64-unknown-freebsd14.0/bits/gthr-default.h:144:1:
note: candidate: 'int __gthrw_pthread_rwlock_unlock(pthread_rwlock**)'
144 | __gthrw(pthread_rwlock_unlock)
| ^~~~~~~
gmake[6]: *** [Makefile:585: floating_from_chars.lo] Error 1
gmake[6]: Leaving directory
'/home/kargl/gcc/obj/x86_64-unknown-freebsd14.0/libstdc++-v3/src/c++17'
gmake[5]: *** [Makefile:784: all-recursive] Error 1
gmake[5]: Leaving directory
'/home/kargl/gcc/obj/x86_64-unknown-freebsd14.0/libstdc++-v3/src'
gmake[4]: *** [Makefile:576: all-recursive] Error 1
gmake[4]: Leaving directory
'/home/kargl/gcc/obj/x86_64-unknown-freebsd14.0/libstdc++-v3'
gmake[3]: *** [Makefile:501: all] Error 2
gmake[3]: Leaving directory
'/home/kargl/gcc/obj/x86_64-unknown-freebsd14.0/libstdc++-v3'
gmake[2]: *** [Makefile:18284: all-stage1-target-libstdc++-v3] Error 2
gmake[2]: Leaving directory '/home/kargl/gcc/obj'
gmake[1]: *** [Makefile:26171: stage1-bubble] Error 2
gmake[1]: Leaving directory '/home/kargl/gcc/obj'
gmake: *** [Makefile:26524: bootstrap] Error 2
--
steve
libstdc++ implements shared mutex with pthread_rwlock, which can conflict
with the pthread_rwlock usage in libgcc. Lipeng, please limit the
pthread_rwlock
usage in libgcc only when __cplusplus isn't defined.
I've just noticed that r14-6425-gb806c88fab3f9c added the rwlock
functions to gthr-posix.h when __cplusplus isn't defined.
Did nobody consider whether libstdc++ might want to also use these
definitions in gthr-posix.h? Now we have them defined twice in two
different places, but they're ialmost identical. That seems silly.
The only difference between the definitions in libstdc++ and in
gthr-posix.h are that libstdc++ has:
# ifndef PTHREAD_RWLOCK_INITIALIZER
and it wraps pthread_rwlock_init and pthread_rwlock_destroy when the
static initializer is not defined. Does libgfortran not need to
support older systems where that macro is not defined?
I see code in libgfortran which does:
#ifdef __GTHREAD_RWLOCK_INIT
Is that correct? gthr-posix.h defines it unconditionally:
#define __GTHREAD_RWLOCK_INIT PTHREAD_RWLOCK_INITIALIZER
