* [LTP] [PATCH] realtime/prio-preempt: take cpu isolation into consideration
@ 2024-07-10 3:24 Shizhao Chen
2024-07-10 6:13 ` Li Wang
0 siblings, 1 reply; 6+ messages in thread
From: Shizhao Chen @ 2024-07-10 3:24 UTC (permalink / raw)
To: ltp, Li Wang, Eder Zulian
By default the test starts N-1 busy threads to monopolize N-1 available CPUs,
where N is the number of all available CPUs. However, when CPU isolation is
applied, this will lead to a hang scenario where all housekeeping CPUs are
hogged as isolated CPUs do not share the N-1 busy threads.
Signed-off-by: Shizhao Chen <shichen@redhat.com>
---
.../realtime/func/prio-preempt/prio-preempt.c | 18 +++++++++++++++---
1 file changed, 15 insertions(+), 3 deletions(-)
diff --git a/testcases/realtime/func/prio-preempt/prio-preempt.c b/testcases/realtime/func/prio-preempt/prio-preempt.c
index 9bd5e7ad8..79d2115a7 100644
--- a/testcases/realtime/func/prio-preempt/prio-preempt.c
+++ b/testcases/realtime/func/prio-preempt/prio-preempt.c
@@ -59,6 +59,7 @@
*
*****************************************************************************/
+#define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
@@ -287,6 +288,17 @@ void *master_thread(void *arg)
return NULL;
}
+int get_numcpus(void)
+{
+ cpu_set_t mask;
+ CPU_ZERO(&mask);
+
+ /* Get the number of cpus accessible to the current process */
+ sched_getaffinity(getpid(), sizeof(mask), &mask);
+
+ return CPU_COUNT(&mask);
+}
+
int main(int argc, char *argv[])
{
int pri_boost, numcpus;
@@ -295,10 +307,10 @@ int main(int argc, char *argv[])
pass_criteria = CHECK_LIMIT;
rt_init("hin:", parse_args, argc, argv);
- numcpus = sysconf(_SC_NPROCESSORS_ONLN);
+ numcpus = get_numcpus();
- /* Max no. of busy threads should always be less than/equal the no. of cpus
- Otherwise, the box will hang */
+ /* Max no. of busy threads should always be less than/equal the no. of
+ housekeeping cpus. Otherwise, the box will hang */
if (rt_threads == -1 || rt_threads > numcpus) {
rt_threads = numcpus;
--
2.45.2
--
Mailing list info: https://lists.linux.it/listinfo/ltp
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [LTP] [PATCH] realtime/prio-preempt: take cpu isolation into consideration
2024-07-10 3:24 [LTP] [PATCH] realtime/prio-preempt: take cpu isolation into consideration Shizhao Chen
@ 2024-07-10 6:13 ` Li Wang
2024-07-10 6:27 ` Li Wang
0 siblings, 1 reply; 6+ messages in thread
From: Li Wang @ 2024-07-10 6:13 UTC (permalink / raw)
To: Shizhao Chen; +Cc: Eder Zulian, ltp
Hi Shizhao,
On Wed, Jul 10, 2024 at 11:24 AM Shizhao Chen <shichen@redhat.com> wrote:
> By default the test starts N-1 busy threads to monopolize N-1 available
> CPUs,
> where N is the number of all available CPUs. However, when CPU isolation is
> applied, this will lead to a hang scenario where all housekeeping CPUs are
> hogged as isolated CPUs do not share the N-1 busy threads.
>
> Signed-off-by: Shizhao Chen <shichen@redhat.com>
> ---
> .../realtime/func/prio-preempt/prio-preempt.c | 18 +++++++++++++++---
> 1 file changed, 15 insertions(+), 3 deletions(-)
>
> diff --git a/testcases/realtime/func/prio-preempt/prio-preempt.c
> b/testcases/realtime/func/prio-preempt/prio-preempt.c
> index 9bd5e7ad8..79d2115a7 100644
> --- a/testcases/realtime/func/prio-preempt/prio-preempt.c
> +++ b/testcases/realtime/func/prio-preempt/prio-preempt.c
> @@ -59,6 +59,7 @@
> *
>
> *****************************************************************************/
>
> +#define _GNU_SOURCE
> #include <stdio.h>
> #include <stdlib.h>
> #include <signal.h>
> @@ -287,6 +288,17 @@ void *master_thread(void *arg)
> return NULL;
> }
>
> +int get_numcpus(void)
> +{
> + cpu_set_t mask;
> + CPU_ZERO(&mask);
> +
> + /* Get the number of cpus accessible to the current process */
> + sched_getaffinity(getpid(), sizeof(mask), &mask);
> +
> + return CPU_COUNT(&mask);
> +}
+
> int main(int argc, char *argv[])
> {
> int pri_boost, numcpus;
> @@ -295,10 +307,10 @@ int main(int argc, char *argv[])
> pass_criteria = CHECK_LIMIT;
> rt_init("hin:", parse_args, argc, argv);
>
> - numcpus = sysconf(_SC_NPROCESSORS_ONLN);
> + numcpus = get_numcpus();
>
Maybe we could make use of LTP lib function tst_ncpus_available directly?
Seems the new get_numcpus() did a dup work on that.
Otherwise, looks good to me.
> - /* Max no. of busy threads should always be less than/equal the
> no. of cpus
> - Otherwise, the box will hang */
> + /* Max no. of busy threads should always be less than/equal the
> no. of
> + housekeeping cpus. Otherwise, the box will hang */
>
> if (rt_threads == -1 || rt_threads > numcpus) {
> rt_threads = numcpus;
> --
> 2.45.2
>
>
--
Regards,
Li Wang
--
Mailing list info: https://lists.linux.it/listinfo/ltp
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [LTP] [PATCH] realtime/prio-preempt: take cpu isolation into consideration
2024-07-10 6:13 ` Li Wang
@ 2024-07-10 6:27 ` Li Wang
2024-07-10 13:12 ` [LTP] [PATCH v2] " Shizhao Chen
2024-07-10 13:16 ` [LTP] [PATCH] " Shizhao Chen
0 siblings, 2 replies; 6+ messages in thread
From: Li Wang @ 2024-07-10 6:27 UTC (permalink / raw)
To: Shizhao Chen; +Cc: Eder Zulian, ltp
On Wed, Jul 10, 2024 at 2:13 PM Li Wang <liwang@redhat.com> wrote:
> Hi Shizhao,
>
> On Wed, Jul 10, 2024 at 11:24 AM Shizhao Chen <shichen@redhat.com> wrote:
>
>> By default the test starts N-1 busy threads to monopolize N-1 available
>> CPUs,
>> where N is the number of all available CPUs. However, when CPU isolation
>> is
>> applied, this will lead to a hang scenario where all housekeeping CPUs are
>> hogged as isolated CPUs do not share the N-1 busy threads.
>>
>> Signed-off-by: Shizhao Chen <shichen@redhat.com>
>> ---
>> .../realtime/func/prio-preempt/prio-preempt.c | 18 +++++++++++++++---
>> 1 file changed, 15 insertions(+), 3 deletions(-)
>>
>> diff --git a/testcases/realtime/func/prio-preempt/prio-preempt.c
>> b/testcases/realtime/func/prio-preempt/prio-preempt.c
>> index 9bd5e7ad8..79d2115a7 100644
>> --- a/testcases/realtime/func/prio-preempt/prio-preempt.c
>> +++ b/testcases/realtime/func/prio-preempt/prio-preempt.c
>> @@ -59,6 +59,7 @@
>> *
>>
>> *****************************************************************************/
>>
>> +#define _GNU_SOURCE
>> #include <stdio.h>
>> #include <stdlib.h>
>> #include <signal.h>
>> @@ -287,6 +288,17 @@ void *master_thread(void *arg)
>> return NULL;
>> }
>>
>> +int get_numcpus(void)
>> +{
>> + cpu_set_t mask;
>> + CPU_ZERO(&mask);
>> +
>> + /* Get the number of cpus accessible to the current process */
>> + sched_getaffinity(getpid(), sizeof(mask), &mask);
>> +
>> + return CPU_COUNT(&mask);
>> +}
>
> +
>> int main(int argc, char *argv[])
>> {
>> int pri_boost, numcpus;
>> @@ -295,10 +307,10 @@ int main(int argc, char *argv[])
>> pass_criteria = CHECK_LIMIT;
>> rt_init("hin:", parse_args, argc, argv);
>>
>> - numcpus = sysconf(_SC_NPROCESSORS_ONLN);
>> + numcpus = get_numcpus();
>>
>
> Maybe we could make use of LTP lib function tst_ncpus_available directly?
> Seems the new get_numcpus() did a dup work on that.
>
Oops, seems the real-time tests does not include ltp library.
So you patch make sense from this point, but maybe we
need to refine the function to consider more situations.
e.g. uses a fixed-size cpu_set_t structure, which might not be
sufficient on systems with a large number of CPUs.
>
> Otherwise, looks good to me.
>
>
>> - /* Max no. of busy threads should always be less than/equal the
>> no. of cpus
>> - Otherwise, the box will hang */
>> + /* Max no. of busy threads should always be less than/equal the
>> no. of
>> + housekeeping cpus. Otherwise, the box will hang */
>>
>> if (rt_threads == -1 || rt_threads > numcpus) {
>> rt_threads = numcpus;
>> --
>> 2.45.2
>>
>>
>
> --
> Regards,
> Li Wang
>
--
Regards,
Li Wang
--
Mailing list info: https://lists.linux.it/listinfo/ltp
^ permalink raw reply [flat|nested] 6+ messages in thread
* [LTP] [PATCH v2] realtime/prio-preempt: take cpu isolation into consideration
2024-07-10 6:27 ` Li Wang
@ 2024-07-10 13:12 ` Shizhao Chen
2024-07-11 6:56 ` Li Wang
2024-07-10 13:16 ` [LTP] [PATCH] " Shizhao Chen
1 sibling, 1 reply; 6+ messages in thread
From: Shizhao Chen @ 2024-07-10 13:12 UTC (permalink / raw)
To: ltp, Li Wang; +Cc: Eder Zulian
By default the test starts N-1 busy threads to monopolize N-1 available CPUs,
where N is the number of all available CPUs. However, when CPU isolation is
applied, this will lead to a hang scenario where all housekeeping CPUs are
hogged as isolated CPUs do not share the N-1 busy threads.
Signed-off-by: Shizhao Chen <shichen@redhat.com>
---
.../realtime/func/prio-preempt/prio-preempt.c | 20 ++++++++++++++++---
1 file changed, 17 insertions(+), 3 deletions(-)
diff --git a/testcases/realtime/func/prio-preempt/prio-preempt.c b/testcases/realtime/func/prio-preempt/prio-preempt.c
index 9bd5e7ad8..16abc1184 100644
--- a/testcases/realtime/func/prio-preempt/prio-preempt.c
+++ b/testcases/realtime/func/prio-preempt/prio-preempt.c
@@ -59,6 +59,7 @@
*
*****************************************************************************/
+#define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
@@ -287,6 +288,19 @@ void *master_thread(void *arg)
return NULL;
}
+int get_numcpus(void)
+{
+ long numcpus_conf = sysconf(_SC_NPROCESSORS_CONF);
+ size_t size = CPU_ALLOC_SIZE(numcpus_conf);
+ cpu_set_t *cpuset = CPU_ALLOC(numcpus_conf);
+
+ CPU_ZERO_S(size, cpuset);
+ /* Get the number of cpus accessible to the current process */
+ sched_getaffinity(0, size, cpuset);
+
+ return CPU_COUNT_S(size, cpuset);
+}
+
int main(int argc, char *argv[])
{
int pri_boost, numcpus;
@@ -295,10 +309,10 @@ int main(int argc, char *argv[])
pass_criteria = CHECK_LIMIT;
rt_init("hin:", parse_args, argc, argv);
- numcpus = sysconf(_SC_NPROCESSORS_ONLN);
+ numcpus = get_numcpus();
- /* Max no. of busy threads should always be less than/equal the no. of cpus
- Otherwise, the box will hang */
+ /* Max no. of busy threads should always be less than/equal the no. of
+ housekeeping cpus. Otherwise, the box will hang */
if (rt_threads == -1 || rt_threads > numcpus) {
rt_threads = numcpus;
--
2.45.2
--
Mailing list info: https://lists.linux.it/listinfo/ltp
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [LTP] [PATCH] realtime/prio-preempt: take cpu isolation into consideration
2024-07-10 6:27 ` Li Wang
2024-07-10 13:12 ` [LTP] [PATCH v2] " Shizhao Chen
@ 2024-07-10 13:16 ` Shizhao Chen
1 sibling, 0 replies; 6+ messages in thread
From: Shizhao Chen @ 2024-07-10 13:16 UTC (permalink / raw)
To: Li Wang; +Cc: Eder Zulian, ltp
Thanks for the review! I just sent a v2 which is basically a minimized
version of tst_ncpus_available.
On Wed, Jul 10, 2024 at 2:27 PM Li Wang <liwang@redhat.com> wrote:
>
>
>
> On Wed, Jul 10, 2024 at 2:13 PM Li Wang <liwang@redhat.com> wrote:
>>
>> Hi Shizhao,
>>
>> On Wed, Jul 10, 2024 at 11:24 AM Shizhao Chen <shichen@redhat.com> wrote:
>>>
>>> By default the test starts N-1 busy threads to monopolize N-1 available CPUs,
>>> where N is the number of all available CPUs. However, when CPU isolation is
>>> applied, this will lead to a hang scenario where all housekeeping CPUs are
>>> hogged as isolated CPUs do not share the N-1 busy threads.
>>>
>>> Signed-off-by: Shizhao Chen <shichen@redhat.com>
>>> ---
>>> .../realtime/func/prio-preempt/prio-preempt.c | 18 +++++++++++++++---
>>> 1 file changed, 15 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/testcases/realtime/func/prio-preempt/prio-preempt.c b/testcases/realtime/func/prio-preempt/prio-preempt.c
>>> index 9bd5e7ad8..79d2115a7 100644
>>> --- a/testcases/realtime/func/prio-preempt/prio-preempt.c
>>> +++ b/testcases/realtime/func/prio-preempt/prio-preempt.c
>>> @@ -59,6 +59,7 @@
>>> *
>>> *****************************************************************************/
>>>
>>> +#define _GNU_SOURCE
>>> #include <stdio.h>
>>> #include <stdlib.h>
>>> #include <signal.h>
>>> @@ -287,6 +288,17 @@ void *master_thread(void *arg)
>>> return NULL;
>>> }
>>>
>>> +int get_numcpus(void)
>>> +{
>>> + cpu_set_t mask;
>>> + CPU_ZERO(&mask);
>>> +
>>> + /* Get the number of cpus accessible to the current process */
>>> + sched_getaffinity(getpid(), sizeof(mask), &mask);
>>> +
>>> + return CPU_COUNT(&mask);
>>> +}
>>>
>>> +
>>> int main(int argc, char *argv[])
>>> {
>>> int pri_boost, numcpus;
>>> @@ -295,10 +307,10 @@ int main(int argc, char *argv[])
>>> pass_criteria = CHECK_LIMIT;
>>> rt_init("hin:", parse_args, argc, argv);
>>>
>>> - numcpus = sysconf(_SC_NPROCESSORS_ONLN);
>>> + numcpus = get_numcpus();
>>
>>
>> Maybe we could make use of LTP lib function tst_ncpus_available directly?
>> Seems the new get_numcpus() did a dup work on that.
>
>
> Oops, seems the real-time tests does not include ltp library.
> So you patch make sense from this point, but maybe we
> need to refine the function to consider more situations.
>
> e.g. uses a fixed-size cpu_set_t structure, which might not be
> sufficient on systems with a large number of CPUs.
>
>
>>
>>
>> Otherwise, looks good to me.
>>
>>>
>>> - /* Max no. of busy threads should always be less than/equal the no. of cpus
>>> - Otherwise, the box will hang */
>>> + /* Max no. of busy threads should always be less than/equal the no. of
>>> + housekeeping cpus. Otherwise, the box will hang */
>>>
>>> if (rt_threads == -1 || rt_threads > numcpus) {
>>> rt_threads = numcpus;
>>> --
>>> 2.45.2
>>>
>>
>>
>> --
>> Regards,
>> Li Wang
>
>
>
> --
> Regards,
> Li Wang
--
Mailing list info: https://lists.linux.it/listinfo/ltp
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [LTP] [PATCH v2] realtime/prio-preempt: take cpu isolation into consideration
2024-07-10 13:12 ` [LTP] [PATCH v2] " Shizhao Chen
@ 2024-07-11 6:56 ` Li Wang
0 siblings, 0 replies; 6+ messages in thread
From: Li Wang @ 2024-07-11 6:56 UTC (permalink / raw)
To: Shizhao Chen; +Cc: Eder Zulian, ltp
Hi Shizhao,
Patch merged, thanks!
--
Regards,
Li Wang
--
Mailing list info: https://lists.linux.it/listinfo/ltp
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2024-07-11 6:57 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2024-07-10 3:24 [LTP] [PATCH] realtime/prio-preempt: take cpu isolation into consideration Shizhao Chen
2024-07-10 6:13 ` Li Wang
2024-07-10 6:27 ` Li Wang
2024-07-10 13:12 ` [LTP] [PATCH v2] " Shizhao Chen
2024-07-11 6:56 ` Li Wang
2024-07-10 13:16 ` [LTP] [PATCH] " Shizhao Chen
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox