Re: [PATCH for 5.1 3/3] rseq/selftests: Adapt number of threads to the number of detected cpus
From: shuah
Date: Fri Apr 19 2019 - 14:31:43 EST
On 4/19/19 7:48 AM, Mathieu Desnoyers wrote:
----- On Apr 19, 2019, at 9:42 AM, Mathieu Desnoyers mathieu.desnoyers@xxxxxxxxxxxx wrote:
----- On Apr 19, 2019, at 8:55 AM, Mathieu Desnoyers
mathieu.desnoyers@xxxxxxxxxxxx wrote:
----- On Apr 19, 2019, at 8:41 AM, Mathieu Desnoyers
mathieu.desnoyers@xxxxxxxxxxxx wrote:
----- On Apr 19, 2019, at 6:38 AM, Ingo Molnar mingo@xxxxxxxxxx wrote:
* Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx> 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 <mathieu.desnoyers@xxxxxxxxxxxx>
Cc: Shuah Khan <shuah@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Joel Fernandes <joelaf@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Dave Watson <davejwatson@xxxxxx>
Cc: Will Deacon <will.deacon@xxxxxxx>
Cc: Andi Kleen <andi@xxxxxxxxxxxxxx>
Cc: linux-kselftest@xxxxxxxxxxxxxxx
Cc: "H . Peter Anvin" <hpa@xxxxxxxxx>
Cc: Chris Lameter <cl@xxxxxxxxx>
Cc: Russell King <linux@xxxxxxxxxxxxxxxx>
Cc: Michael Kerrisk <mtk.manpages@xxxxxxxxx>
Cc: "Paul E . McKenney" <paulmck@xxxxxxxxxxxxxxxxxx>
Cc: Paul Turner <pjt@xxxxxxxxxx>
Cc: Boqun Feng <boqun.feng@xxxxxxxxx>
Cc: Josh Triplett <josh@xxxxxxxxxxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: Ben Maurer <bmaurer@xxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
---
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 ?
Didn't see problems when I tested it before applying it to
linux-kselftest next.
I have gcc version 7.3.0 (Ubuntu 7.3.0-27ubuntu1~18.04)
thanks,
-- Shuah