* [LTP] [PATCH] read_all: limit per cpu nodes to first ten cpus
@ 2021-04-13 13:50 Jan Stancek
2021-04-13 13:57 ` Petr Vorel
2021-04-15 11:44 ` Cyril Hrubis
0 siblings, 2 replies; 4+ messages in thread
From: Jan Stancek @ 2021-04-13 13:50 UTC (permalink / raw)
To: ltp
Some per cpu sysfs entries have high lock contention and when
this is combined with systems which have many CPUs (meaning they
also have many per cpu sysfs entries) the test spends most of
time on these nodes and occasionally also hits timeout.
For example, these entries are largest contributor on HPE Apollo 70
(aarch64, 256 CPUs):
/sys/kernel/tracing/per_cpu/cpu247/*
/sys/devices/system/cpu/cpu239/acpi_cppc/*
To preserve some coverage, add a blacklist rule that will ignore
"cpu" nodes with 2 or more digits.
Before:
real 4m47.747s
user 0m0.885s
sys 5m47.909s
After:
real 0m42.696s
user 0m0.911s
sys 0m4.759s
Signed-off-by: Jan Stancek <jstancek@redhat.com>
---
testcases/kernel/fs/read_all/read_all.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/testcases/kernel/fs/read_all/read_all.c b/testcases/kernel/fs/read_all/read_all.c
index 79c6b93fad73..a4123220afbe 100644
--- a/testcases/kernel/fs/read_all/read_all.c
+++ b/testcases/kernel/fs/read_all/read_all.c
@@ -87,6 +87,7 @@ static char *blacklist[] = {
"/sys/kernel/debug/*",
"/sys/devices/platform/*/eeprom",
"/sys/devices/platform/*/nvmem",
+ "/sys/*/cpu??*(?)/*", /* cpu* entries with 2 or more digits */
};
static int queue_pop(struct queue *q, char *buf)
--
2.18.1
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [LTP] [PATCH] read_all: limit per cpu nodes to first ten cpus
2021-04-13 13:50 [LTP] [PATCH] read_all: limit per cpu nodes to first ten cpus Jan Stancek
@ 2021-04-13 13:57 ` Petr Vorel
2021-04-15 11:44 ` Cyril Hrubis
1 sibling, 0 replies; 4+ messages in thread
From: Petr Vorel @ 2021-04-13 13:57 UTC (permalink / raw)
To: ltp
Hi Jan,
> Some per cpu sysfs entries have high lock contention and when
> this is combined with systems which have many CPUs (meaning they
> also have many per cpu sysfs entries) the test spends most of
> time on these nodes and occasionally also hits timeout.
> For example, these entries are largest contributor on HPE Apollo 70
> (aarch64, 256 CPUs):
> /sys/kernel/tracing/per_cpu/cpu247/*
> /sys/devices/system/cpu/cpu239/acpi_cppc/*
Acked-by: Petr Vorel <petr.vorel@gmail.com>
Kind regards,
Petr
^ permalink raw reply [flat|nested] 4+ messages in thread
* [LTP] [PATCH] read_all: limit per cpu nodes to first ten cpus
2021-04-13 13:50 [LTP] [PATCH] read_all: limit per cpu nodes to first ten cpus Jan Stancek
2021-04-13 13:57 ` Petr Vorel
@ 2021-04-15 11:44 ` Cyril Hrubis
2021-04-15 13:29 ` Jan Stancek
1 sibling, 1 reply; 4+ messages in thread
From: Cyril Hrubis @ 2021-04-15 11:44 UTC (permalink / raw)
To: ltp
Hi!
Sounds reasonable to me as well.
Acked-by: Cyril Hrubis <chrubis@suse.cz>
--
Cyril Hrubis
chrubis@suse.cz
^ permalink raw reply [flat|nested] 4+ messages in thread
* [LTP] [PATCH] read_all: limit per cpu nodes to first ten cpus
2021-04-15 11:44 ` Cyril Hrubis
@ 2021-04-15 13:29 ` Jan Stancek
0 siblings, 0 replies; 4+ messages in thread
From: Jan Stancek @ 2021-04-15 13:29 UTC (permalink / raw)
To: ltp
----- Original Message -----
> Hi!
> Sounds reasonable to me as well.
Thanks for review, pushed.
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2021-04-15 13:29 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-04-13 13:50 [LTP] [PATCH] read_all: limit per cpu nodes to first ten cpus Jan Stancek
2021-04-13 13:57 ` Petr Vorel
2021-04-15 11:44 ` Cyril Hrubis
2021-04-15 13:29 ` Jan Stancek
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.