----- On Apr 19, 2019, at 9:42 AM, Mathieu Desnoyers [email protected] wrote:
> ----- 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: FWIW, if I add an empty asm volatile (""); here after the label, gcc-8 -O2 builds "something" which is a bogus assembler (an endless loop) : main: .LFB24: .cfi_startproc .L2: subq $8, %rsp .cfi_def_cfa_offset 16 #APP # 6 "test-asm-goto.c" 1 jmp .L2 # 0 "" 2 #NO_APP movl %fs:var@tpoff, %edx leaq .LC0(%rip), %rsi movl $1, %edi xorl %eax, %eax call __printf_chk@PLT xorl %eax, %eax addq $8, %rsp .cfi_def_cfa_offset 8 ret .cfi_endproc Thoughts ? Thanks, Mathieu > 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 -- Mathieu Desnoyers EfficiOS Inc. http://www.efficios.com
