From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mathieu Desnoyers Subject: Re: [PATCH for 5.1 3/3] rseq/selftests: Adapt number of threads to the number of detected cpus Date: Fri, 19 Apr 2019 08:55:07 -0400 (EDT) Message-ID: <1266612341.87.1555678507226.JavaMail.zimbra@efficios.com> References: <20190305194755.2602-1-mathieu.desnoyers@efficios.com> <20190305194755.2602-4-mathieu.desnoyers@efficios.com> <20190419103847.GA111210@gmail.com> <1444419838.71.1555677682502.JavaMail.zimbra@efficios.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1444419838.71.1555677682502.JavaMail.zimbra@efficios.com> Sender: linux-kernel-owner@vger.kernel.org To: Ingo Molnar Cc: Thomas Gleixner , linux-kernel , linux-api , Peter Zijlstra , "Paul E . McKenney" , Boqun Feng , Andy Lutomirski , Dave Watson , Paul Turner , Andrew Morton , Russell King , Ingo Molnar , "H. Peter Anvin" , Andi Kleen , Chris Lameter , Ben Maurer , rostedt , Josh Triplett , Linus Torvalds , Catalin Marinas , Will List-Id: linux-api@vger.kernel.org ----- On Apr 19, 2019, at 8:41 AM, Mathieu Desnoyers mathieu.desnoyers@efficios.com wrote: > ----- On Apr 19, 2019, at 6:38 AM, Ingo Molnar mingo@kernel.org wrote: > >> * Mathieu Desnoyers wrote: >> >>> On smaller systems, running a test with 200 threads can take a long >>> time on machines with smaller number of CPUs. >>> >>> Detect the number of online cpus at test runtime, and multiply that >>> by 6 to have 6 rseq threads per cpu preempting each other. >>> >>> Signed-off-by: Mathieu Desnoyers >>> Cc: Shuah Khan >>> Cc: Thomas Gleixner >>> Cc: Joel Fernandes >>> Cc: Peter Zijlstra >>> Cc: Catalin Marinas >>> Cc: Dave Watson >>> Cc: Will Deacon >>> Cc: Andi Kleen >>> Cc: linux-kselftest@vger.kernel.org >>> Cc: "H . Peter Anvin" >>> Cc: Chris Lameter >>> Cc: Russell King >>> Cc: Michael Kerrisk >>> Cc: "Paul E . McKenney" >>> Cc: Paul Turner >>> Cc: Boqun Feng >>> Cc: Josh Triplett >>> Cc: Steven Rostedt >>> Cc: Ben Maurer >>> Cc: Andy Lutomirski >>> Cc: Andrew Morton >>> Cc: Linus Torvalds >>> --- >>> tools/testing/selftests/rseq/run_param_test.sh | 7 +++++-- >>> 1 file changed, 5 insertions(+), 2 deletions(-) >>> >>> diff --git a/tools/testing/selftests/rseq/run_param_test.sh >>> b/tools/testing/selftests/rseq/run_param_test.sh >>> index 3acd6d75ff9f..e426304fd4a0 100755 >>> --- a/tools/testing/selftests/rseq/run_param_test.sh >>> +++ b/tools/testing/selftests/rseq/run_param_test.sh >>> @@ -1,6 +1,8 @@ >>> #!/bin/bash >>> # SPDX-License-Identifier: GPL-2.0+ or MIT >>> >>> +NR_CPUS=`grep '^processor' /proc/cpuinfo | wc -l` >>> + >>> EXTRA_ARGS=${@} >>> >>> OLDIFS="$IFS" >>> @@ -28,15 +30,16 @@ IFS="$OLDIFS" >>> >>> REPS=1000 >>> SLOW_REPS=100 >>> +NR_THREADS=$((6*${NR_CPUS})) >>> >>> function do_tests() >>> { >>> local i=0 >>> while [ "$i" -lt "${#TEST_LIST[@]}" ]; do >>> echo "Running test ${TEST_NAME[$i]}" >>> - ./param_test ${TEST_LIST[$i]} -r ${REPS} ${@} ${EXTRA_ARGS} || exit 1 >>> + ./param_test ${TEST_LIST[$i]} -r ${REPS} -t ${NR_THREADS} ${@} ${EXTRA_ARGS} >>> || exit 1 >>> echo "Running compare-twice test ${TEST_NAME[$i]}" >>> - ./param_test_compare_twice ${TEST_LIST[$i]} -r ${REPS} ${@} ${EXTRA_ARGS} || >>> exit 1 >>> + ./param_test_compare_twice ${TEST_LIST[$i]} -r ${REPS} -t ${NR_THREADS} ${@} >>> ${EXTRA_ARGS} || exit 1 >>> let "i++" >>> done >>> } >> >> BTW., when trying to build the rseq self-tests I get this build failure: >> >> dagon:~/tip/tools/testing/selftests/rseq> make >> gcc -O2 -Wall -g -I./ -I../../../../usr/include/ -L./ -Wl,-rpath=./ -shared >> -fPIC rseq.c -lpthread -o >> /home/mingo/tip/tools/testing/selftests/rseq/librseq.so >> gcc -O2 -Wall -g -I./ -I../../../../usr/include/ -L./ -Wl,-rpath=./ basic_test.c >> -lpthread -lrseq -o /home/mingo/tip/tools/testing/selftests/rseq/basic_test >> gcc -O2 -Wall -g -I./ -I../../../../usr/include/ -L./ -Wl,-rpath=./ >> basic_percpu_ops_test.c -lpthread -lrseq -o >> /home/mingo/tip/tools/testing/selftests/rseq/basic_percpu_ops_test >> /usr/bin/ld: /tmp/ccuHTWnZ.o: in function `rseq_cmpeqv_storev': >> /home/mingo/tip/tools/testing/selftests/rseq/./rseq-x86.h:84: undefined >> reference to `.L8' >> /usr/bin/ld: /home/mingo/tip/tools/testing/selftests/rseq/./rseq-x86.h:84: >> undefined reference to `.L49' >> /usr/bin/ld: /tmp/ccuHTWnZ.o: in function `rseq_cmpnev_storeoffp_load': >> /home/mingo/tip/tools/testing/selftests/rseq/./rseq-x86.h:141: undefined >> reference to `.L57' >> /usr/bin/ld: /tmp/ccuHTWnZ.o:(__rseq_failure+0x8): undefined reference to `.L8' >> /usr/bin/ld: /tmp/ccuHTWnZ.o:(__rseq_failure+0x14): undefined reference to >> `.L49' >> /usr/bin/ld: /tmp/ccuHTWnZ.o:(__rseq_failure+0x20): undefined reference to >> `.L55' >> collect2: error: ld returned 1 exit status >> make: *** [Makefile:22: >> /home/mingo/tip/tools/testing/selftests/rseq/basic_percpu_ops_test] Error 1 >> >> Is this a known problem, or do I miss something from my build environment >> perhaps? Vanilla 64-bit Ubuntu 18.10 (Cosmic). > > It works fine with gcc-7 (gcc version 7.3.0 (Ubuntu 7.3.0-16ubuntu3)) > but indeed I get the same failure with gcc-8 (gcc version 8.0.1 20180414 > (experimental) [trunk revision 259383] (Ubuntu 8-20180414-1ubuntu2)). > > Thanks for reporting! I will investigate. It looks like gcc-8 optimize away the target of asm goto labels when there are more than one of them on x86-64. I'll try to come up with a simpler reproducer. Thanks, Mathieu -- Mathieu Desnoyers EfficiOS Inc. http://www.efficios.com