问题
I am trying to parallelize my program in C with OpenACC 2.5 on Ubuntu 16.04 LTS. After a simple modification which is just adding one line, I can compile all my .c files to .o files. In the linking step, pgcc compiler shows
undefined reference to `__pgi_uacc_multicorestart'
and
undefined reference to `__pgi_uacc_multicoreend'
. Google search shows nothing related to these error message. Please help me on this problem.
Here is the information and source code related to my system and program. I try to post the essential part and please let me know if you need anything else.
OS, software:
LSB Version: core-9.20160110ubuntu0.2-amd64:core-9.20160110ubuntu0.2-noarch:printing-9.20160110ubuntu0.2-amd64:printing-9.20160110ubuntu0.2-noarch:security-9.20160110ubuntu0.2-amd64:security-9.20160110ubuntu0.2-noarch
Distributor ID: Ubuntu
Description: Ubuntu 16.04.3 LTS
Release: 16.04
Codename: xenial
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-linux-gnu/5/lto-wrapper
Target: x86_64-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Ubuntu 5.4.0-6ubuntu1~16.04.5' --with-bugurl=file:///usr/share/doc/gcc-5/README.Bugs --enable-languages=c,ada,c++,java,go,d,fortran,objc,obj-c++ --prefix=/usr --program-suffix=-5 --enable-shared --enable-linker-build-id --libexecdir=/usr/lib --without-included-gettext --enable-threads=posix --libdir=/usr/lib --enable-nls --with-sysroot=/ --enable-clocale=gnu --enable-libstdcxx-debug --enable-libstdcxx-time=yes --with-default-libstdcxx-abi=new --enable-gnu-unique-object --disable-vtable-verify --enable-libmpx --enable-plugin --with-system-zlib --disable-browser-plugin --enable-java-awt=gtk --enable-gtk-cairo --with-java-home=/usr/lib/jvm/java-1.5.0-gcj-5-amd64/jre --enable-java-home --with-jvm-root-dir=/usr/lib/jvm/java-1.5.0-gcj-5-amd64 --with-jvm-jar-dir=/usr/lib/jvm-exports/java-1.5.0-gcj-5-amd64 --with-arch-directory=amd64 --with-ecj-jar=/usr/share/java/eclipse-ecj.jar --enable-objc-gc --enable-multiarch --disable-werror --with-arch-32=i686 --with-abi=m64 --with-multilib-list=m32,m64,mx32 --enable-multilib --with-tune=generic --enable-checking=release --build=x86_64-linux-gnu --host=x86_64-linux-gnu --target=x86_64-linux-gnu
Thread model: posix
gcc version 5.4.0 20160609 (Ubuntu 5.4.0-6ubuntu1~16.04.5)
pgcc 17.10-0 64-bit target on x86-64 Linux -tp haswell
PGI Compilers and Tools
Copyright (c) 2017, NVIDIA CORPORATION. All rights reserved.
.bashrc:
#CUDA
export PATH=/usr/local/cuda/bin:$PATH;
export LD_LIBRARY_PATH=/usr/local/cuda/lib64:$LD_LIBRARY_PATH;
#####
ulimit -s unlimited
#####
#Environment Modules
source /usr/share/modules/init/bash
module add /opt/pgi/modulefiles/pgi64/17.10
module add /opt/pgi/modulefiles/openmpi/2.1.2/2017
#####
#intel compiler
source /opt/intel/bin/compilervars.sh intel64
#intel vtune
source /opt/intel/vtune_amplifier/amplxe-vars.sh
#intel advisor
source /opt/intel/advisor/advixe-vars.sh
#intel inspector
source /opt/intel/inspector/inspxe-vars.sh
#intel mkl
source /opt/intel/mkl/bin/mklvars.sh intel64
makefile:
CC = pgcc
CFLAGS_pgcc = -O0 -Minform=inform -Minfo -ta=multicore -g -pg -Mprof=time
CFLAGS = $(CFLAGS_$(CC)) -c
LFLAGS = $(LFLAGS_$(CC)) -L${MKLROOT}/lib/intel64 -lmkl_rt -lpthread -lm -ldl
IFLAGS = $(IFLAGS_$(CC)) -I${MKLROOT}/include
<content is partially neglected>
serial: $(C_OBJ)
$(CC) $(IFLAGS) $(CFLAGS) -c msg_ser.c
$(CC) $(IFLAGS) -o dplbe $(C_OBJ) msg_ser.o $(LFLAGS)
error message:
lbe.o: In function `equilibrium_distrib':
<content is partially neglected>lbe.c:548: undefined reference to `__pgi_uacc_multicorestart'
<content is partially neglected>lbe.c:583: undefined reference to `__pgi_uacc_multicoreend'
makefile:57: recipe for target 'serial' failed
make: *** [serial] Error 2
lbe.c, to which I only add one line as a babystep to use OpenACC.
#include "header.h"
extern int max_x, max_y, max_z;
extern int num_x, x_min, x_max;
extern int num_proc, n_proc;
extern double tau[2], tau_v[2];
<content is partially neglected>
void equilibrium_distrib(int xy, int z, double ***velcs_df, double dt,
struct vector forceDen, struct vector *correctedVel, double *f_eq)
{
<content is partially neglected>
#pragma acc kernels
{
for(int q=0; q < 19; q++)
{
double term1 = (c_x[q] * correctedVel->x + c_y[q] * correctedVel->y +
c_z[q] * correctedVel->z)*3.;
double term2 = 0.5*term1*term1;
f_eq[q] = weight[q]*density*(1 + term1 + term2 - term3);
}
}
}
compile lbe.c to lbe.o message:
pgcc-Warning--Mprof=time is not supported
PGC-I-0222-Redundant definition for symbol __THROW (/usr/include/x86_64-linux-gnu/sys/cdefs.h: 74)
PGC-I-0222-Redundant definition for symbol __extension__ (/usr/include/x86_64-linux-gnu/sys/cdefs.h: 358)
lbe_zcol:
<content is partially neglected>
equilibrium_distrib:
558, FMA (fused multiply-add) instruction(s) generated
559, FMA (fused multiply-add) instruction(s) generated
560, FMA (fused multiply-add) instruction(s) generated
565, FMA (fused multiply-add) instruction(s) generated
566, FMA (fused multiply-add) instruction(s) generated
567, FMA (fused multiply-add) instruction(s) generated
573, FMA (fused multiply-add) instruction(s) generated
577, Loop is parallelizable
Generating Multicore code
577, #pragma acc loop gang
580, FMA (fused multiply-add) instruction(s) generated
回答1:
You're most likely missing "-ta=multicore" on your link line. Try adding the following to your makefile:
LFLAGS_pgcc = -O0 -Minform=inform -Minfo -ta=multicore -g -pg
Note that the "-Mprof" flag is no longer supported so should be removed.
回答2:
Thank you very much for your useful hint. I went to check my makefile and found out that it is actually a little bit mess up or said out of date. The "Variables Used by Implicit Rules" in the old makefile are not completely in the correct format. It is why the pgcc compiler and linker did not work correctly.
Here is a new makefile wrote by myself, it is more clean and neat.
CC = pgcc
CFLAGS = -I${MKLROOT}/include -O0 -Minform=inform -Minfo -ta=multicore -g -pg
LDFLAGS = -L${MKLROOT}/lib/intel64
LDLIBS = -lmkl_rt -lpthread -lm -ldl
C_OBJ = main.o driver.o update.o lbe_update.o \
bnodes.o bnodes_init.o bnodes_dp.o implicit_force.o lbe.o modes_write.o \
lub.o velcs_update.o hs3d.o n_list.o objects_init.o objects_map.o \
clusters.o cluster_force.o cluster_update.o cj_grad.o \
global_sums.o utils.o output.o \
init_sphere.o ran_num.o get_forces.o verlet_update.o aggregation.o \
jacobi_eigenvalue.o
clean:
rm -f *.o dplbe
%.o : %.c
$(CC) $(CFLAGS) -c $< -o $@ $(LDFLAGS) $(LDLIBS)
serial: $(C_OBJ)
$(CC) $(CFLAGS) -c msg_ser.c $(LDFLAGS) $(LDLIBS)
$(CC) $(CFLAGS) -o dplbe $(C_OBJ) msg_ser.o $(LDFLAGS) $(LDLIBS)
来源：https://stackoverflow.com/questions/47580080/how-to-solve-pgccopenacc-linker-error-pgi-uacc-multicorestart-pgi-uacc