* [LTP] [PATCH v2] syscalls/prctl08: New test for prctl() with PR_{SET, GET}_TIMERSLACK
@ 2019-07-27 8:27 Yang Xu
2019-07-30 9:07 ` Cyril Hrubis
0 siblings, 1 reply; 3+ messages in thread
From: Yang Xu @ 2019-07-27 8:27 UTC (permalink / raw)
To: ltp
Signed-off-by: Yang Xu <xuyang2018.jy@cn.fujitsu.com>
-----
v1->v2:
1)remove useless struct member
2)compare time should be (sleep + timer_slack) if time is not enough large
---
include/lapi/prctl.h | 5 +
runtest/syscalls | 1 +
testcases/kernel/syscalls/prctl/.gitignore | 1 +
testcases/kernel/syscalls/prctl/Makefile | 1 +
testcases/kernel/syscalls/prctl/prctl08.c | 118 +++++++++++++++++++++
5 files changed, 126 insertions(+)
create mode 100644 testcases/kernel/syscalls/prctl/prctl08.c
diff --git a/include/lapi/prctl.h b/include/lapi/prctl.h
index 8ee492259..0b4e196c3 100644
--- a/include/lapi/prctl.h
+++ b/include/lapi/prctl.h
@@ -19,6 +19,11 @@
# define PR_SET_SECCOMP 22
#endif
+#ifndef PR_SET_TIMERSLACK
+# define PR_SET_TIMERSLACK 29
+# define PR_GET_TIMERSLACK 30
+#endif
+
#ifndef PR_SET_CHILD_SUBREAPER
# define PR_SET_CHILD_SUBREAPER 36
# define PR_GET_CHILD_SUBREAPER 37
diff --git a/runtest/syscalls b/runtest/syscalls
index 0114b002b..48836f422 100644
--- a/runtest/syscalls
+++ b/runtest/syscalls
@@ -872,6 +872,7 @@ prctl04 prctl04
prctl05 prctl05
prctl06 prctl06
prctl07 prctl07
+prctl08 prctl08
pread01 pread01
pread01_64 pread01_64
diff --git a/testcases/kernel/syscalls/prctl/.gitignore b/testcases/kernel/syscalls/prctl/.gitignore
index 2178db366..fe36a8e0f 100644
--- a/testcases/kernel/syscalls/prctl/.gitignore
+++ b/testcases/kernel/syscalls/prctl/.gitignore
@@ -6,3 +6,4 @@
/prctl06
/prctl06_execve
/prctl07
+/prctl08
diff --git a/testcases/kernel/syscalls/prctl/Makefile b/testcases/kernel/syscalls/prctl/Makefile
index cf19507c0..d3c41ff4e 100644
--- a/testcases/kernel/syscalls/prctl/Makefile
+++ b/testcases/kernel/syscalls/prctl/Makefile
@@ -21,5 +21,6 @@ top_srcdir ?= ../../../..
include $(top_srcdir)/include/mk/testcases.mk
prctl07: LDLIBS += $(CAP_LIBS)
+prctl08: LDLIBS+=-lrt
include $(top_srcdir)/include/mk/generic_leaf_target.mk
diff --git a/testcases/kernel/syscalls/prctl/prctl08.c b/testcases/kernel/syscalls/prctl/prctl08.c
new file mode 100644
index 000000000..92b9bfe41
--- /dev/null
+++ b/testcases/kernel/syscalls/prctl/prctl08.c
@@ -0,0 +1,118 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2019 FUJITSU LIMITED. All rights reserved.
+ * Author: Yang Xu <xuyang2018.jy@cn.fujitsu.com>
+ *
+ * Test PR_GET_TIMERSLACK and PR_SET_TIMERSLACK of prctl(2).
+ * 1)Each thread has two associated timer slack values: a "default"
+ * value, and a "current" value. PR_SET_TIMERSLACK sets the "current"
+ * timer slack value for the calling thread.
+ * 2)When a new thread is created, the two timer slack values are made
+ * the same as the "current" value of the creating thread.
+ * 3)The maximum timer slack value is ULONG_MAX. On 32bit machines, it
+ * is a valid value(about 4s). On 64bit machines, it is about 500 years
+ * and no person will set this over 4s. prctl return value is int, so
+ * we test themaximum value is INT_MAX.
+ * 4)we also check /proc/[pid]/timerslack_ns if it is supported.
+ */
+
+#include <sys/prctl.h>
+#include <string.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <linux/limits.h>
+#include "lapi/syscalls.h"
+#include "lapi/prctl.h"
+#include "tst_timer.h"
+#include "tst_test.h"
+
+#define PROC_NS_PATH "/proc/self/timerslack_ns"
+
+static struct tcase {
+ unsigned long setvalue;
+ unsigned long cmptime;
+} tcases[] = {
+ {1, 50000},
+ {70000, 120000},
+ {INT_MAX, 50000},
+};
+
+static int proc_flag = 1;
+
+static void check_proc_ns(char *message, unsigned long value)
+{
+ unsigned long proc_value;
+
+ SAFE_FILE_SCANF(PROC_NS_PATH, "%lu", &proc_value);
+ if (proc_value == value)
+ tst_res(TPASS, "%s %s got %lu expectedly",
+ message, PROC_NS_PATH, proc_value);
+ else
+ tst_res(TFAIL, "%s %s expected %lu got %lu",
+ message, PROC_NS_PATH, value, proc_value);
+}
+
+static void check_get_timerslack(char *message, unsigned long value)
+{
+ TEST(prctl(PR_GET_TIMERSLACK));
+ if ((unsigned long)TST_RET == value)
+ tst_res(TPASS, "%s prctl(PR_GET_TIMERSLACK) got %lu expectedly",
+ message, value);
+ else
+ tst_res(TFAIL, "%s prctl(PR_GET_TIMERSLACK) expected %lu got %lu",
+ message, value, TST_RET);
+
+ if (proc_flag)
+ check_proc_ns(message, value);
+}
+
+static void verify_prctl(unsigned int n)
+{
+ struct tcase *tc = &tcases[n];
+ int pid;
+
+ struct timespec timereq = { .tv_sec = 0, .tv_nsec = 50000 };
+ struct timespec timecmp = { .tv_sec = 0, .tv_nsec = tc->cmptime};
+
+ TEST(prctl(PR_SET_TIMERSLACK, tc->setvalue));
+ if (TST_RET == -1) {
+ tst_res(TFAIL | TTERRNO, "prctl(PR_SET_TIMERSLACK, %lu) failed",
+ tc->setvalue);
+ return;
+ }
+ tst_res(TPASS, "prctl(PR_SET_TIMERSLACK, %lu) success", tc->setvalue);
+
+ pid = SAFE_FORK();
+ if (pid == 0) {
+ check_get_timerslack("child process", tc->setvalue);
+ /* A value of 0 means using default */
+ prctl(PR_SET_TIMERSLACK, 0);
+ check_get_timerslack("After set 0, child process", tc->setvalue);
+
+ tst_timer_start(CLOCK_MONOTONIC);
+ TEST(nanosleep(&timereq, NULL));
+ tst_timer_stop();
+
+ if (tst_timespec_lt(tst_timer_elapsed(), timecmp))
+ tst_brk(TFAIL, "nanosleep() slept less than timecmp");
+
+ tst_res(TPASS, "nanosleep() slept more than timecmp, %llius",
+ tst_timer_elapsed_us());
+ exit(0);
+ }
+}
+
+static void setup(void)
+{
+ if (access(PROC_NS_PATH, F_OK) == -1) {
+ tst_res(TCONF, "proc doesn't support timerslack_ns interface");
+ proc_flag = 0;
+ }
+}
+
+static struct tst_test test = {
+ .setup = setup,
+ .test = verify_prctl,
+ .tcnt = ARRAY_SIZE(tcases),
+ .forks_child = 1,
+};
--
2.18.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* [LTP] [PATCH v2] syscalls/prctl08: New test for prctl() with PR_{SET, GET}_TIMERSLACK
2019-07-27 8:27 [LTP] [PATCH v2] syscalls/prctl08: New test for prctl() with PR_{SET, GET}_TIMERSLACK Yang Xu
@ 2019-07-30 9:07 ` Cyril Hrubis
2019-07-30 10:01 ` Yang Xu
0 siblings, 1 reply; 3+ messages in thread
From: Cyril Hrubis @ 2019-07-30 9:07 UTC (permalink / raw)
To: ltp
Hi!
> +static struct tcase {
> + unsigned long setvalue;
> + unsigned long cmptime;
> +} tcases[] = {
> + {1, 50000},
> + {70000, 120000},
> + {INT_MAX, 50000},
> +};
> +
> +static int proc_flag = 1;
> +
> +static void check_proc_ns(char *message, unsigned long value)
> +{
> + unsigned long proc_value;
> +
> + SAFE_FILE_SCANF(PROC_NS_PATH, "%lu", &proc_value);
> + if (proc_value == value)
> + tst_res(TPASS, "%s %s got %lu expectedly",
> + message, PROC_NS_PATH, proc_value);
> + else
> + tst_res(TFAIL, "%s %s expected %lu got %lu",
> + message, PROC_NS_PATH, value, proc_value);
> +}
> +
> +static void check_get_timerslack(char *message, unsigned long value)
> +{
> + TEST(prctl(PR_GET_TIMERSLACK));
> + if ((unsigned long)TST_RET == value)
> + tst_res(TPASS, "%s prctl(PR_GET_TIMERSLACK) got %lu expectedly",
> + message, value);
> + else
> + tst_res(TFAIL, "%s prctl(PR_GET_TIMERSLACK) expected %lu got %lu",
> + message, value, TST_RET);
> +
> + if (proc_flag)
> + check_proc_ns(message, value);
> +}
> +
> +static void verify_prctl(unsigned int n)
> +{
> + struct tcase *tc = &tcases[n];
> + int pid;
> +
> + struct timespec timereq = { .tv_sec = 0, .tv_nsec = 50000 };
> + struct timespec timecmp = { .tv_sec = 0, .tv_nsec = tc->cmptime};
> +
> + TEST(prctl(PR_SET_TIMERSLACK, tc->setvalue));
> + if (TST_RET == -1) {
> + tst_res(TFAIL | TTERRNO, "prctl(PR_SET_TIMERSLACK, %lu) failed",
> + tc->setvalue);
> + return;
> + }
> + tst_res(TPASS, "prctl(PR_SET_TIMERSLACK, %lu) success", tc->setvalue);
> +
> + pid = SAFE_FORK();
> + if (pid == 0) {
> + check_get_timerslack("child process", tc->setvalue);
> + /* A value of 0 means using default */
> + prctl(PR_SET_TIMERSLACK, 0);
Why do we reset the slack before the measurements?
> + check_get_timerslack("After set 0, child process", tc->setvalue);
> +
> + tst_timer_start(CLOCK_MONOTONIC);
> + TEST(nanosleep(&timereq, NULL));
> + tst_timer_stop();
> +
> + if (tst_timespec_lt(tst_timer_elapsed(), timecmp))
> + tst_brk(TFAIL, "nanosleep() slept less than timecmp");
I do not get what we are trying to assert here.
As far as I understand it the timer slack is a way how to inform kernel
that it's okay if the timers are slightly less precise. However the
timer still can fire somewhere between sleep time and sleep time +
slack, or even maybe later if the system is under load.
BTW we do have a formula that tries to compute maximal time the timers
should sleep based on timer slack in lib/tst_timer_test.c but even with
that we have to take more samples and compute truncated mean because
single short sleep may be delayed unless it's a RT kernel...
> + tst_res(TPASS, "nanosleep() slept more than timecmp, %llius",
> + tst_timer_elapsed_us());
> + exit(0);
> + }
> +}
> +
> +static void setup(void)
> +{
> + if (access(PROC_NS_PATH, F_OK) == -1) {
> + tst_res(TCONF, "proc doesn't support timerslack_ns interface");
> + proc_flag = 0;
> + }
> +}
> +
> +static struct tst_test test = {
> + .setup = setup,
> + .test = verify_prctl,
> + .tcnt = ARRAY_SIZE(tcases),
> + .forks_child = 1,
> +};
> --
> 2.18.1
>
>
>
>
> --
> Mailing list info: https://lists.linux.it/listinfo/ltp
--
Cyril Hrubis
chrubis@suse.cz
^ permalink raw reply [flat|nested] 3+ messages in thread
* [LTP] [PATCH v2] syscalls/prctl08: New test for prctl() with PR_{SET, GET}_TIMERSLACK
2019-07-30 9:07 ` Cyril Hrubis
@ 2019-07-30 10:01 ` Yang Xu
0 siblings, 0 replies; 3+ messages in thread
From: Yang Xu @ 2019-07-30 10:01 UTC (permalink / raw)
To: ltp
> Hi!
>> +static struct tcase {
>> + unsigned long setvalue;
>> + unsigned long cmptime;
>> +} tcases[] = {
>> + {1, 50000},
>> + {70000, 120000},
>> + {INT_MAX, 50000},
>> +};
>> +
>> +static int proc_flag = 1;
>> +
>> +static void check_proc_ns(char *message, unsigned long value)
>> +{
>> + unsigned long proc_value;
>> +
>> + SAFE_FILE_SCANF(PROC_NS_PATH, "%lu",&proc_value);
>> + if (proc_value == value)
>> + tst_res(TPASS, "%s %s got %lu expectedly",
>> + message, PROC_NS_PATH, proc_value);
>> + else
>> + tst_res(TFAIL, "%s %s expected %lu got %lu",
>> + message, PROC_NS_PATH, value, proc_value);
>> +}
>> +
>> +static void check_get_timerslack(char *message, unsigned long value)
>> +{
>> + TEST(prctl(PR_GET_TIMERSLACK));
>> + if ((unsigned long)TST_RET == value)
>> + tst_res(TPASS, "%s prctl(PR_GET_TIMERSLACK) got %lu expectedly",
>> + message, value);
>> + else
>> + tst_res(TFAIL, "%s prctl(PR_GET_TIMERSLACK) expected %lu got %lu",
>> + message, value, TST_RET);
>> +
>> + if (proc_flag)
>> + check_proc_ns(message, value);
>> +}
>> +
>> +static void verify_prctl(unsigned int n)
>> +{
>> + struct tcase *tc =&tcases[n];
>> + int pid;
>> +
>> + struct timespec timereq = { .tv_sec = 0, .tv_nsec = 50000 };
>> + struct timespec timecmp = { .tv_sec = 0, .tv_nsec = tc->cmptime};
>> +
>> + TEST(prctl(PR_SET_TIMERSLACK, tc->setvalue));
>> + if (TST_RET == -1) {
>> + tst_res(TFAIL | TTERRNO, "prctl(PR_SET_TIMERSLACK, %lu) failed",
>> + tc->setvalue);
>> + return;
>> + }
>> + tst_res(TPASS, "prctl(PR_SET_TIMERSLACK, %lu) success", tc->setvalue);
>> +
>> + pid = SAFE_FORK();
>> + if (pid == 0) {
>> + check_get_timerslack("child process", tc->setvalue);
>> + /* A value of 0 means using default */
>> + prctl(PR_SET_TIMERSLACK, 0);
> Why do we reset the slack before the measurements?
Hi Cyril
I reset it because I want to test whether default timer_slack in child process is the same as the current value
of the creating thread.
I also sent a patch about PR_SET_TIMERSLACK to man-page, as below:
https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/commit/?id=c14f79303f2885f7f4f4bf0d63922551b520a4b8
>> + check_get_timerslack("After set 0, child process", tc->setvalue);
>> +
>> + tst_timer_start(CLOCK_MONOTONIC);
>> + TEST(nanosleep(&timereq, NULL));
>> + tst_timer_stop();
>> +
>> + if (tst_timespec_lt(tst_timer_elapsed(), timecmp))
>> + tst_brk(TFAIL, "nanosleep() slept less than timecmp");
> I do not get what we are trying to assert here.
>
> As far as I understand it the timer slack is a way how to inform kernel
> that it's okay if the timers are slightly less precise. However the
> timer still can fire somewhere between sleep time and sleep time +
> slack, or even maybe later if the system is under load.
Yes. timer still can fire somewhere in [sleep, sleep+slack] range even later.
> BTW we do have a formula that tries to compute maximal time the timers
> should sleep based on timer slack in lib/tst_timer_test.c but even with
> that we have to take more samples and compute truncated mean because
> single short sleep may be delayed unless it's a RT kernel...
>
Yes . Agree. Single short sleep may be delayed and I will take more samples.
>> + tst_res(TPASS, "nanosleep() slept more than timecmp, %llius",
>> + tst_timer_elapsed_us());
>> + exit(0);
>> + }
>> +}
>> +
>> +static void setup(void)
>> +{
>> + if (access(PROC_NS_PATH, F_OK) == -1) {
>> + tst_res(TCONF, "proc doesn't support timerslack_ns interface");
>> + proc_flag = 0;
>> + }
>> +}
>> +
>> +static struct tst_test test = {
>> + .setup = setup,
>> + .test = verify_prctl,
>> + .tcnt = ARRAY_SIZE(tcases),
>> + .forks_child = 1,
>> +};
>> --
>> 2.18.1
>>
>>
>>
>>
>> --
>> Mailing list info: https://lists.linux.it/listinfo/ltp
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2019-07-27 8:27 [LTP] [PATCH v2] syscalls/prctl08: New test for prctl() with PR_{SET, GET}_TIMERSLACK Yang Xu
2019-07-30 9:07 ` Cyril Hrubis
2019-07-30 10:01 ` Yang Xu
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