Patch for Linux Futexes
Hi,
When using the Linux Skype client under FreeBSD I sometimes see that the
Audio disappears in the one direction. When I check ps auxw I see
skype is stuck on a so-called Futex. I looked into the Linux futex code
and see that wakeup_one() is used instead of wakeup(). Maybe others can
test too and verify if replacing wakeup_one() by wakeup() makes any
difference in for Linux applications using Futexes.
--HPS
diff --git a/sys/compat/linux/linux_futex.c b/sys/compat/linux/linux_futex.c
index 9b4c92f..e893bf4 100644
--- a/sys/compat/linux/linux_futex.c
+++ b/sys/compat/linux/linux_futex.c
@@ -498,7 +498,7 @@ futex_wake(struct futex *f, int n, uint32_t bitset)
wp-wp_flags |= FUTEX_WP_REMOVED;
TAILQ_REMOVE(f-f_waiting_proc, wp, wp_list);
LIN_SDT_PROBE1(futex, futex_wake, wakeup, wp);
- wakeup_one(wp);
+ wakeup(wp);
if (++count == n)
break;
}
@@ -525,7 +525,7 @@ futex_requeue(struct futex *f, int n, struct futex *f2, int
n2)
wp-wp_flags |= FUTEX_WP_REMOVED;
TAILQ_REMOVE(f-f_waiting_proc, wp, wp_list);
LIN_SDT_PROBE1(futex, futex_requeue, wakeup, wp);
- wakeup_one(wp);
+ wakeup(wp);
} else {
LIN_SDT_PROBE3(futex, futex_requeue, requeue,
f-f_uaddr, wp, f2-f_uaddr);
___
freebsd-current@freebsd.org mailing list
http://lists.freebsd.org/mailman/listinfo/freebsd-current
To unsubscribe, send any mail to freebsd-current-unsubscr...@freebsd.org
Re: Patch for Linux Futexes
On Thu, May 22, 2014 at 01:06:22PM +0200, Hans Petter Selasky wrote:
Hi,
When using the Linux Skype client under FreeBSD I sometimes see that the
Audio disappears in the one direction. When I check ps auxw I see
skype is stuck on a so-called Futex. I looked into the Linux futex code
and see that wakeup_one() is used instead of wakeup(). Maybe others can
test too and verify if replacing wakeup_one() by wakeup() makes any
difference in for Linux applications using Futexes.
is it fixes the problem for you? as the author of it I should to look
back to find the reason of using wakeup_one(). and check this patch on
nptl tests.
--HPS
diff --git a/sys/compat/linux/linux_futex.c b/sys/compat/linux/linux_futex.c
index 9b4c92f..e893bf4 100644
--- a/sys/compat/linux/linux_futex.c
+++ b/sys/compat/linux/linux_futex.c
@@ -498,7 +498,7 @@ futex_wake(struct futex *f, int n, uint32_t bitset)
wp-wp_flags |= FUTEX_WP_REMOVED;
TAILQ_REMOVE(f-f_waiting_proc, wp, wp_list);
LIN_SDT_PROBE1(futex, futex_wake, wakeup, wp);
- wakeup_one(wp);
+ wakeup(wp);
if (++count == n)
break;
}
@@ -525,7 +525,7 @@ futex_requeue(struct futex *f, int n, struct futex *f2,
int n2)
wp-wp_flags |= FUTEX_WP_REMOVED;
TAILQ_REMOVE(f-f_waiting_proc, wp, wp_list);
LIN_SDT_PROBE1(futex, futex_requeue, wakeup, wp);
- wakeup_one(wp);
+ wakeup(wp);
} else {
LIN_SDT_PROBE3(futex, futex_requeue, requeue,
f-f_uaddr, wp, f2-f_uaddr);
___
freebsd-current@freebsd.org mailing list
http://lists.freebsd.org/mailman/listinfo/freebsd-current
To unsubscribe, send any mail to freebsd-current-unsubscr...@freebsd.org
--
Have fun!
chd
pgpaP_dny5N5D.pgp
Description: PGP signature
Re: Patch for Linux Futexes
On 05/22/14 14:18, Chagin Dmitry wrote: On Thu, May 22, 2014 at 01:06:22PM +0200, Hans Petter Selasky wrote: Hi, When using the Linux Skype client under FreeBSD I sometimes see that the Audio disappears in the one direction. When I check ps auxw I see skype is stuck on a so-called Futex. I looked into the Linux futex code and see that wakeup_one() is used instead of wakeup(). Maybe others can test too and verify if replacing wakeup_one() by wakeup() makes any difference in for Linux applications using Futexes. is it fixes the problem for you? So far looks better, but I still have to test more. --HPS ___ freebsd-current@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-current To unsubscribe, send any mail to freebsd-current-unsubscr...@freebsd.org
Re: Patch for Linux Futexes
On Thu, May 22, 2014 at 01:06:22PM +0200, Hans Petter Selasky wrote:
Hi,
When using the Linux Skype client under FreeBSD I sometimes see that the
Audio disappears in the one direction. When I check ps auxw I see
skype is stuck on a so-called Futex. I looked into the Linux futex code
and see that wakeup_one() is used instead of wakeup(). Maybe others can
test too and verify if replacing wakeup_one() by wakeup() makes any
difference in for Linux applications using Futexes.
generally speaking the patch is not correct as futex_wake() should
wakeup n waiters which is specified by user space. and i think that
futex_wake() is correct.
so we must take a close look at futex_requeue() and FUTEX_WAKE_OP.
--HPS
diff --git a/sys/compat/linux/linux_futex.c b/sys/compat/linux/linux_futex.c
index 9b4c92f..e893bf4 100644
--- a/sys/compat/linux/linux_futex.c
+++ b/sys/compat/linux/linux_futex.c
@@ -498,7 +498,7 @@ futex_wake(struct futex *f, int n, uint32_t bitset)
wp-wp_flags |= FUTEX_WP_REMOVED;
TAILQ_REMOVE(f-f_waiting_proc, wp, wp_list);
LIN_SDT_PROBE1(futex, futex_wake, wakeup, wp);
- wakeup_one(wp);
+ wakeup(wp);
if (++count == n)
break;
}
@@ -525,7 +525,7 @@ futex_requeue(struct futex *f, int n, struct futex *f2,
int n2)
wp-wp_flags |= FUTEX_WP_REMOVED;
TAILQ_REMOVE(f-f_waiting_proc, wp, wp_list);
LIN_SDT_PROBE1(futex, futex_requeue, wakeup, wp);
- wakeup_one(wp);
+ wakeup(wp);
} else {
LIN_SDT_PROBE3(futex, futex_requeue, requeue,
f-f_uaddr, wp, f2-f_uaddr);
___
freebsd-current@freebsd.org mailing list
http://lists.freebsd.org/mailman/listinfo/freebsd-current
To unsubscribe, send any mail to freebsd-current-unsubscr...@freebsd.org
--
Have fun!
chd
pgpJnQTecka1X.pgp
Description: PGP signature
Re: Patch for Linux Futexes
On 05/22/14 20:23, Chagin Dmitry wrote: On Thu, May 22, 2014 at 01:06:22PM +0200, Hans Petter Selasky wrote: Hi, When using the Linux Skype client under FreeBSD I sometimes see that the Audio disappears in the one direction. When I check ps auxw I see skype is stuck on a so-called Futex. I looked into the Linux futex code and see that wakeup_one() is used instead of wakeup(). Maybe others can test too and verify if replacing wakeup_one() by wakeup() makes any difference in for Linux applications using Futexes. generally speaking the patch is not correct as futex_wake() should wakeup n waiters which is specified by user space. and i think that futex_wake() is correct. so we must take a close look at futex_requeue() and FUTEX_WAKE_OP. Hi, I still see the issue with Skype, even when running with my small patch :-( I'll try to profile the threads in Skype while it is running like expected and observe any differences when it is not working, when I have some more time, using kgdb. I guess td-td_slptick can be used to figure out if a thread has been left behind, because Skype creates many threads ... Thank you for your time! --HPS ___ freebsd-current@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-current To unsubscribe, send any mail to freebsd-current-unsubscr...@freebsd.org
