Re: Add wakeup_with() before 7.0?

This would be very useful, if you have time it might make sense to do
this for condvars as well. At the minimum you should fix the comment
for WAKEUP_ONE to be "Only wakeup _one_ thread".

* Jeff Roberson <jroberson@xxxxxxxxxxxxxx> [070628 12:40] wrote:
I propose to add a new api for wakeup before 7.0. This new api would
accept a wait channel and a flags argument. here's the relevant part of
the diff:

+void wakeup_with(void *chan, int flags) __nonnull(1);
+#define WAKEUP_ONE 0x00001 /* Only wakeup on thread.
*/
+#define WAKEUP_ALL 0x00002 /* Wake-up all waiters. */
+#define WAKEUP_LOCAL 0x00004 /* Wake-up on the local
cpu. */
+#define WAKEUP_TAIL 0x00008 /* Wake-up the newest
waiter. */

This allows wakeup callers to hint the scheduler about various
information. WAKEUP_LOCAL would allow us to prefer affinity for the
waking cpu. I have patches to use this in pipe code and socket buffer
code that improve performance in some workloads. WAKEUP_TAIL could be
used for accept() which I have heard can significantly improve webserver
performance.

To implement this change sched_wakeup() and setrunnable() need the flags
plummed all the way through. I would like feedback on whether people
think the api breakage should go in now to enable these optimizations for
7.0, potentially without committing users of these flags right away.
Alternatively we could break the api later or just skip it until 8.0.

Thanks,
Jeff
_______________________________________________
freebsd-arch@xxxxxxxxxxx mailing list
http://lists.freebsd.org/mailman/listinfo/freebsd-arch
To unsubscribe, send any mail to "freebsd-arch-unsubscribe@xxxxxxxxxxx"

--
- Alfred Perlstein
_______________________________________________
freebsd-arch@xxxxxxxxxxx mailing list
http://lists.freebsd.org/mailman/listinfo/freebsd-arch
To unsubscribe, send any mail to "freebsd-arch-unsubscribe@xxxxxxxxxxx"