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 09:48:43 -0400 (EDT) Message-ID: <1863599735.141.1555681723685.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> <1266612341.87.1555678507226.JavaMail.zimbra@efficios.com> <614774674.134.1555681346941.JavaMail.zimbra@efficios.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <614774674.134.1555681346941.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 9:42 AM, Mathieu Desnoyers mathieu.desnoyers@efficios.com wrote: > ----- On Apr 19, 2019, at 8:55 AM, Mathieu Desnoyers > mathieu.desnoyers@efficios.com wrote: > >> ----- 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. > > 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 From mboxrd@z Thu Jan 1 00:00:00 1970 From: mathieu.desnoyers at efficios.com (Mathieu Desnoyers) Date: Fri, 19 Apr 2019 09:48:43 -0400 (EDT) Subject: [PATCH for 5.1 3/3] rseq/selftests: Adapt number of threads to the number of detected cpus In-Reply-To: <614774674.134.1555681346941.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> <1266612341.87.1555678507226.JavaMail.zimbra@efficios.com> <614774674.134.1555681346941.JavaMail.zimbra@efficios.com> Message-ID: <1863599735.141.1555681723685.JavaMail.zimbra@efficios.com> ----- On Apr 19, 2019, at 9:42 AM, Mathieu Desnoyers mathieu.desnoyers at efficios.com wrote: > ----- On Apr 19, 2019, at 8:55 AM, Mathieu Desnoyers > mathieu.desnoyers at efficios.com wrote: > >> ----- On Apr 19, 2019, at 8:41 AM, Mathieu Desnoyers >> mathieu.desnoyers at efficios.com wrote: >> >>> ----- On Apr 19, 2019, at 6:38 AM, Ingo Molnar mingo at 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 at 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. > > 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 at tpoff, %edx leaq .LC0(%rip), %rsi movl $1, %edi xorl %eax, %eax call __printf_chk at 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 From mboxrd@z Thu Jan 1 00:00:00 1970 From: mathieu.desnoyers@efficios.com (Mathieu Desnoyers) Date: Fri, 19 Apr 2019 09:48:43 -0400 (EDT) Subject: [PATCH for 5.1 3/3] rseq/selftests: Adapt number of threads to the number of detected cpus In-Reply-To: <614774674.134.1555681346941.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> <1266612341.87.1555678507226.JavaMail.zimbra@efficios.com> <614774674.134.1555681346941.JavaMail.zimbra@efficios.com> Message-ID: <1863599735.141.1555681723685.JavaMail.zimbra@efficios.com> Content-Type: text/plain; charset="UTF-8" Message-ID: <20190419134843.DBN7LrWGGEIlAtDPe48LpOwL4YkUi0l7ZlM45koF3h0@z> ----- On Apr 19, 2019,@9:42 AM, Mathieu Desnoyers mathieu.desnoyers@efficios.com wrote: > ----- On Apr 19, 2019, at 8:55 AM, Mathieu Desnoyers > mathieu.desnoyers@efficios.com wrote: > >> ----- On Apr 19, 2019, at 8:41 AM, Mathieu Desnoyers >> mathieu.desnoyers@efficios.com wrote: >> >>> ----- On Apr 19, 2019,@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 at 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. > > 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 at tpoff, %edx leaq .LC0(%rip), %rsi movl $1, %edi xorl %eax, %eax call __printf_chk at 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 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id DDA8CC282DA for ; Fri, 19 Apr 2019 18:35:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9C024204EC for ; Fri, 19 Apr 2019 18:35:05 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=efficios.com header.i=@efficios.com header.b="ut3rAtdq" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728241AbfDSSfE (ORCPT ); Fri, 19 Apr 2019 14:35:04 -0400 Received: from mail.efficios.com ([167.114.142.138]:39144 "EHLO mail.efficios.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726498AbfDSSfC (ORCPT ); Fri, 19 Apr 2019 14:35:02 -0400 Received: from localhost (ip6-localhost [IPv6:::1]) by mail.efficios.com (Postfix) with ESMTP id BF9CAACA6F; Fri, 19 Apr 2019 09:48:44 -0400 (EDT) Received: from mail.efficios.com ([IPv6:::1]) by localhost (mail02.efficios.com [IPv6:::1]) (amavisd-new, port 10032) with ESMTP id NSysZe375Iga; Fri, 19 Apr 2019 09:48:44 -0400 (EDT) Received: from localhost (ip6-localhost [IPv6:::1]) by mail.efficios.com (Postfix) with ESMTP id 0D030ACA6C; Fri, 19 Apr 2019 09:48:44 -0400 (EDT) DKIM-Filter: OpenDKIM Filter v2.10.3 mail.efficios.com 0D030ACA6C DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=efficios.com; s=default; t=1555681724; bh=naWCnvmvITV9fSLITlaSml2gAPU0rMpr6UUSOtSZcdg=; h=Date:From:To:Message-ID:MIME-Version; b=ut3rAtdqLLsPLVWDNnIYMXo2O3CcpqRHMux6HnXSPp1HPbZ1EHKysqG6DvCqvAu8b TZM87jsGuRKOcAWjz6+GtbmQ1qwn0Rf65Cx8GlN9Wk1rtrVro8k3BteYiHOC26pwwJ LVJEpe8gtzUAGK+Kq+geYH/DxjUWAFE8QNdTmF/LENmlozPd2hz4+h0ZsoFnWp1qrL HwKyb0us7E19R2AteSvrC8pGOZS5kr8uOFtpbXDig0d+jp1XYC7fGSzuNmHs2YojZf 2XZoujmvl53s2DZZuV01+1+mj+J2mdX+DTQpYHWuj2O2T3nOEvlif09dxSo134aZO9 maNBGKFDl1WGQ== X-Virus-Scanned: amavisd-new at efficios.com Received: from mail.efficios.com ([IPv6:::1]) by localhost (mail02.efficios.com [IPv6:::1]) (amavisd-new, port 10026) with ESMTP id 9CqoZjTpX6Ho; Fri, 19 Apr 2019 09:48:43 -0400 (EDT) Received: from mail02.efficios.com (mail02.efficios.com [167.114.142.138]) by mail.efficios.com (Postfix) with ESMTP id DC298ACA5C; Fri, 19 Apr 2019 09:48:43 -0400 (EDT) Date: Fri, 19 Apr 2019 09:48:43 -0400 (EDT) From: Mathieu Desnoyers 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 Deacon , Michael Kerrisk , Joel Fernandes , shuah , linux-kselftest Message-ID: <1863599735.141.1555681723685.JavaMail.zimbra@efficios.com> In-Reply-To: <614774674.134.1555681346941.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> <1266612341.87.1555678507226.JavaMail.zimbra@efficios.com> <614774674.134.1555681346941.JavaMail.zimbra@efficios.com> Subject: Re: [PATCH for 5.1 3/3] rseq/selftests: Adapt number of threads to the number of detected cpus MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-Originating-IP: [167.114.142.138] X-Mailer: Zimbra 8.8.12_GA_3794 (ZimbraWebClient - FF66 (Linux)/8.8.12_GA_3794) Thread-Topic: rseq/selftests: Adapt number of threads to the number of detected cpus Thread-Index: YxJQ2i25qH1y+iSOFfTo74MHmwpaOcIwymvLgob8dFRhKZxfog== Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org ----- On Apr 19, 2019, at 9:42 AM, Mathieu Desnoyers mathieu.desnoyers@efficios.com wrote: > ----- On Apr 19, 2019, at 8:55 AM, Mathieu Desnoyers > mathieu.desnoyers@efficios.com wrote: > >> ----- 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. > > 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