----- On Apr 19, 2019, at 8:55 AM, Mathieu Desnoyers [email protected] wrote:
> ----- On Apr 19, 2019, at 8:41 AM, Mathieu Desnoyers > [email protected] wrote: > >> ----- On Apr 19, 2019, at 6:38 AM, Ingo Molnar [email protected] wrote: >> >>> * Mathieu Desnoyers <[email protected]> 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 <[email protected]> >>>> Cc: Shuah Khan <[email protected]> >>>> Cc: Thomas Gleixner <[email protected]> >>>> Cc: Joel Fernandes <[email protected]> >>>> Cc: Peter Zijlstra <[email protected]> >>>> Cc: Catalin Marinas <[email protected]> >>>> Cc: Dave Watson <[email protected]> >>>> Cc: Will Deacon <[email protected]> >>>> Cc: Andi Kleen <[email protected]> >>>> Cc: [email protected] >>>> Cc: "H . Peter Anvin" <[email protected]> >>>> Cc: Chris Lameter <[email protected]> >>>> Cc: Russell King <[email protected]> >>>> Cc: Michael Kerrisk <[email protected]> >>>> Cc: "Paul E . McKenney" <[email protected]> >>>> Cc: Paul Turner <[email protected]> >>>> Cc: Boqun Feng <[email protected]> >>>> Cc: Josh Triplett <[email protected]> >>>> Cc: Steven Rostedt <[email protected]> >>>> Cc: Ben Maurer <[email protected]> >>>> Cc: Andy Lutomirski <[email protected]> >>>> Cc: Andrew Morton <[email protected]> >>>> Cc: Linus Torvalds <[email protected]> >>>> --- >>>> 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. It appears to be related to gcc-8 mishandling combination of asm goto and thread-local storage input operands on x86-64. Here is a simple reproducer: __thread int var; static int fct(void) { asm goto ( "jmp %l[testlabel]\n\t" : : [var] "m" (var) : : testlabel); return 0; testlabel: return 1; } int main() { return fct(); } building with gcc-7 -O2 is fine. Building with gcc-8 -O0 is fine too. Building with gcc-8 -O1 and -O2 fails with: /tmp/ccuXTFfs.o: In function `main': test-asm-goto.c:(.text.startup+0x1): undefined reference to `.L2' collect2: error: ld returned 1 exit status With gcc-7 -O2, the assembly of main has the .L2 label: main: .LFB1: .cfi_startproc #APP # 5 "test-asm-goto.c" 1 jmp .L2 # 0 "" 2 #NO_APP .L4: .L3: xorl %eax, %eax ret .L2: movl $1, %eax ret .cfi_endproc However, with gcc-8 -O2, it's missing: main: .LFB1: .cfi_startproc .L3: #APP # 5 "test-asm-goto.c" 1 jmp .L2 # 0 "" 2 #NO_APP xorl %eax, %eax ret .cfi_endproc It looks like we have a compiler issue. :-/ Thanks, Mathieu -- Mathieu Desnoyers EfficiOS Inc. http://www.efficios.com
