This patch improves the performance of xnsynch_sleep_on when it is
called with (XN_RELATIVE, XN_NONBLOCK) timeout parameters. For this
purpose, it introduces a new thread info XNNONBLCK that is set in case
xnsynch_sleep_on fails while in XN_NONBLOCK mode. Maybe this should be
solved via a dedicated trylock (but that would duplicate quite some
code), hopefully we can avoid it completely by doing lock stealing on
trylock via (generic) fast locks, even in user space.
---
include/nucleus/thread.h | 1 +
ksrc/nucleus/pod.c | 8 +++++---
ksrc/nucleus/synch.c | 20 +++++++++++++++++---
ksrc/skins/native/mutex.c | 13 +++++++------
ksrc/skins/posix/mutex.c | 5 +----
ksrc/skins/posix/mutex.h | 8 +++++++-
6 files changed, 38 insertions(+), 17 deletions(-)
Index: b/include/nucleus/thread.h
===================================================================
--- a/include/nucleus/thread.h
+++ b/include/nucleus/thread.h
@@ -116,6 +116,7 @@
#define XNROBBED 0x00000020 /**< Robbed from resource ownership */
#define XNATOMIC 0x00000040 /**< In atomic switch from secondary to primary
mode */
#define XNAFFSET 0x00000080 /**< CPU affinity changed from primary mode */
+#define XNNONBLCK 0x00000100 /**< Non-blocking mode prevented suspension */
/* These information flags are available to the real-time interfaces */
#define XNTHREAD_INFO_SPARE0 0x10000000
Index: b/ksrc/nucleus/pod.c
===================================================================
--- a/ksrc/nucleus/pod.c
+++ b/ksrc/nucleus/pod.c
@@ -1401,14 +1401,16 @@ void xnpod_suspend_thread(xnthread_t *th
thread->name, mask);
);
xnthread_clear_info(thread,
- XNRMID | XNTIMEO | XNROBBED);
+ XNRMID | XNTIMEO | XNROBBED |
+ XNNONBLCK);
xnthread_set_info(thread, XNBREAK);
goto unlock_and_exit;
}
#endif /* CONFIG_XENO_OPT_PERVASIVE */
- xnthread_clear_info(thread, XNRMID | XNTIMEO | XNBREAK |
- XNWAKEN | XNROBBED);
+ xnthread_clear_info(thread,
+ XNRMID | XNTIMEO | XNBREAK | XNWAKEN |
+ XNROBBED | XNNONBLCK);
}
/* Don't start the timer for a thread indefinitely delayed by
Index: b/ksrc/nucleus/synch.c
===================================================================
--- a/ksrc/nucleus/synch.c
+++ b/ksrc/nucleus/synch.c
@@ -194,7 +194,8 @@ redo:
if (!owner) {
synch->owner = thread;
- xnthread_clear_info(thread, XNRMID | XNTIMEO | XNBREAK);
+ xnthread_clear_info(thread,
+ XNRMID | XNTIMEO | XNBREAK | XNNONBLCK);
goto unlock_and_exit;
}
@@ -202,11 +203,18 @@ redo:
if (xnthread_test_info(owner, XNWAKEN) && owner->wwake ==
synch) {
/* Ownership is still pending, steal the resource. */
synch->owner = thread;
- xnthread_clear_info(thread, XNRMID | XNTIMEO | XNBREAK);
+ xnthread_clear_info(thread,
+ XNRMID | XNTIMEO | XNBREAK |
+ XNNONBLCK);
xnthread_set_info(owner, XNROBBED);
goto unlock_and_exit;
}
+ if (timeout == XN_NONBLOCK && timeout_mode == XN_RELATIVE) {
+ xnthread_set_info(thread, XNNONBLCK);
+ goto unlock_and_exit;
+ }
+
if (!xnthread_test_state(owner, XNBOOST)) {
owner->bprio = owner->cprio;
xnthread_set_state(owner, XNBOOST);
@@ -220,8 +228,14 @@ redo:
insertpqf(&owner->claimq, &synch->link, thread->cprio);
insertpqf(&synch->pendq, &thread->plink, thread->cprio);
xnsynch_renice_thread(owner, thread->cprio);
- } else
+ } else {
+ if (timeout == XN_NONBLOCK && timeout_mode == XN_RELATIVE) {
+ xnthread_set_info(thread, XNNONBLCK);
+ goto unlock_and_exit;
+ }
+
insertpqf(&synch->pendq, &thread->plink, thread->cprio);
+ }
xnpod_suspend_thread(thread, XNPEND, timeout, timeout_mode, synch);
Index: b/ksrc/skins/native/mutex.c
===================================================================
--- a/ksrc/skins/native/mutex.c
+++ b/ksrc/skins/native/mutex.c
@@ -388,17 +388,18 @@ int rt_mutex_acquire_inner(RT_MUTEX *mut
if (unlikely
(xnthread_test_info(thread,
- XNBREAK | XNRMID | XNROBBED | XNTIMEO))) {
+ XNBREAK | XNNONBLCK | XNRMID | XNROBBED |
+ XNTIMEO))) {
+ if (xnthread_test_info(thread, XNNONBLCK)) {
+ err = -EWOULDBLOCK; /* Try-to-lock failed. */
+ goto cleanup_and_exit;
+ }
if (xnthread_test_info(thread, XNROBBED)) {
xnlock_put_irqrestore(&nklock, s);
goto retry;
}
if (xnthread_test_info(thread, XNTIMEO)) {
- if (timeout_mode == XN_RELATIVE &&
- timeout == XN_NONBLOCK)
- err = -EWOULDBLOCK;
- else
- err = -ETIMEDOUT;
+ err = -ETIMEDOUT;
goto cleanup_and_exit;
}
if (xnthread_test_info(thread, XNBREAK)) {
Index: b/ksrc/skins/posix/mutex.c
===================================================================
--- a/ksrc/skins/posix/mutex.c
+++ b/ksrc/skins/posix/mutex.c
@@ -406,13 +406,10 @@ int pthread_mutex_trylock(pthread_mutex_
err = 0;
}
}
- } else {
+ } else
err =
-pse51_mutex_timedlock_internal(cur, shadow, 1,
XN_RELATIVE, XN_NONBLOCK);
- if (err == ETIMEDOUT)
- err = EBUSY;
- }
cb_read_unlock(&shadow->lock, s);
Index: b/ksrc/skins/posix/mutex.h
===================================================================
--- a/ksrc/skins/posix/mutex.h
+++ b/ksrc/skins/posix/mutex.h
@@ -174,7 +174,13 @@ static inline int pse51_mutex_timedlock_
xnsynch_sleep_on(&mutex->synchbase, timeout, timeout_mode);
if (unlikely
- (xnthread_test_info(cur, XNBREAK | XNRMID | XNROBBED | XNTIMEO))) {
+ (xnthread_test_info(cur,
+ XNBREAK | XNNONBLCK | XNRMID | XNROBBED |
+ XNTIMEO))) {
+ if (xnthread_test_info(cur, XNNONBLCK)) {
+ err = -EBUSY;
+ goto error;
+ }
if (xnthread_test_info(cur, XNROBBED)) {
xnlock_put_irqrestore(&nklock, s);
goto retry_lock;
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