| Message ID | 51dce875f4ad2c234031101cd5c7a85eace53caa.1571225074.git.jstancek@redhat.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [1/2] perf_event_open02: stop groups with hw counters first | expand |
Hi! > Signed-off-by: Jan Stancek <jstancek@redhat.com> > --- > .../kernel/syscalls/perf_event_open/perf_event_open02.c | 15 +++++++++++++++ > 1 file changed, 15 insertions(+) > > diff --git a/testcases/kernel/syscalls/perf_event_open/perf_event_open02.c b/testcases/kernel/syscalls/perf_event_open/perf_event_open02.c > index 1cfe29bb3d8a..6fc6f4afa119 100644 > --- a/testcases/kernel/syscalls/perf_event_open/perf_event_open02.c > +++ b/testcases/kernel/syscalls/perf_event_open/perf_event_open02.c > @@ -52,6 +52,7 @@ Usage is: ./performance_counter02 [-v] > The -v flag makes it print out the values of each counter. > */ > > +#define _GNU_SOURCE > #include <stdio.h> > #include <stddef.h> > #include <stdlib.h> > @@ -222,6 +223,20 @@ static void setup(void) > int i; > struct perf_event_attr tsk_event, hw_event; > > +#ifdef HAVE_SCHED_GETCPU > + cpu_set_t mask; Don't we have to allocate the mask dynamically so that we do not fail on systems with more than CPU_SETSIZE (1024) CPUs? We already have fallback macros for older libc in include/lapi/cpuset.h so that we can use CPU_ALLOC() unconditionally. > + int cpu = sched_getcpu(); > + > + if (cpu == -1) > + tst_brkm(TBROK | TERRNO, NULL, "sched_getcpu() failed"); > + > + CPU_ZERO(&mask); > + CPU_SET(cpu, &mask); > + > + if (sched_setaffinity(0, sizeof(cpu_set_t), &mask) == -1) > + tst_brkm(TBROK | TERRNO, NULL, "sched_setaffinity() failed"); > +#endif > + > /* > * According to perf_event_open's manpage, the official way of > * knowing if perf_event_open() support is enabled is checking for > -- > 1.8.3.1 > > > -- > Mailing list info: https://lists.linux.it/listinfo/ltp
----- Original Message ----- > Hi! > > Signed-off-by: Jan Stancek <jstancek@redhat.com> > > --- > > .../kernel/syscalls/perf_event_open/perf_event_open02.c | 15 > > +++++++++++++++ > > 1 file changed, 15 insertions(+) > > > > diff --git a/testcases/kernel/syscalls/perf_event_open/perf_event_open02.c > > b/testcases/kernel/syscalls/perf_event_open/perf_event_open02.c > > index 1cfe29bb3d8a..6fc6f4afa119 100644 > > --- a/testcases/kernel/syscalls/perf_event_open/perf_event_open02.c > > +++ b/testcases/kernel/syscalls/perf_event_open/perf_event_open02.c > > @@ -52,6 +52,7 @@ Usage is: ./performance_counter02 [-v] > > The -v flag makes it print out the values of each counter. > > */ > > > > +#define _GNU_SOURCE > > #include <stdio.h> > > #include <stddef.h> > > #include <stdlib.h> > > @@ -222,6 +223,20 @@ static void setup(void) > > int i; > > struct perf_event_attr tsk_event, hw_event; > > > > +#ifdef HAVE_SCHED_GETCPU > > + cpu_set_t mask; > > Don't we have to allocate the mask dynamically so that we do not fail on > systems with more than CPU_SETSIZE (1024) CPUs? > > We already have fallback macros for older libc in include/lapi/cpuset.h > so that we can use CPU_ALLOC() unconditionally. Haven't thought of that. I'll look into adding that for v2.
diff --git a/testcases/kernel/syscalls/perf_event_open/perf_event_open02.c b/testcases/kernel/syscalls/perf_event_open/perf_event_open02.c index 1cfe29bb3d8a..6fc6f4afa119 100644 --- a/testcases/kernel/syscalls/perf_event_open/perf_event_open02.c +++ b/testcases/kernel/syscalls/perf_event_open/perf_event_open02.c @@ -52,6 +52,7 @@ Usage is: ./performance_counter02 [-v] The -v flag makes it print out the values of each counter. */ +#define _GNU_SOURCE #include <stdio.h> #include <stddef.h> #include <stdlib.h> @@ -222,6 +223,20 @@ static void setup(void) int i; struct perf_event_attr tsk_event, hw_event; +#ifdef HAVE_SCHED_GETCPU + cpu_set_t mask; + int cpu = sched_getcpu(); + + if (cpu == -1) + tst_brkm(TBROK | TERRNO, NULL, "sched_getcpu() failed"); + + CPU_ZERO(&mask); + CPU_SET(cpu, &mask); + + if (sched_setaffinity(0, sizeof(cpu_set_t), &mask) == -1) + tst_brkm(TBROK | TERRNO, NULL, "sched_setaffinity() failed"); +#endif + /* * According to perf_event_open's manpage, the official way of * knowing if perf_event_open() support is enabled is checking for
Test is failing on -rt kernels quite reliably as reported here: https://lkml.org/lkml/2019/8/14/714 Suspected cause is extra time spend in scheduler, which counts towards test process hw counters. Pin test process to single CPU (doesn't matter which one) to lessen effects from scheduling: ratio Before After mean 5.02582 4.99844 stdev 0.0090435 0.0000272 95+% FAIL 100% PASS Tested with "perf_event_open02: stop groups with hw counters first" patch on RHEL8 kernel-rt 4.18.0-147.rt24.93.el8.x86_64 (HP dl380g7). Signed-off-by: Jan Stancek <jstancek@redhat.com> --- .../kernel/syscalls/perf_event_open/perf_event_open02.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+)