65 messages in org.freebsd.freebsd-smpRe: SMP meeting summary| From | Sent On | Attachments |
|---|---|---|
| Jason Evans | Jun 24, 2000 11:56 pm | |
| Daniel Eischen | Jun 25, 2000 6:58 am | |
| Terry Lambert | Jun 25, 2000 10:12 am | |
| Terry Lambert | Jun 25, 2000 10:36 am | |
| Julian Elischer | Jun 25, 2000 10:41 am | |
| Poul-Henning Kamp | Jun 25, 2000 11:07 am | |
| Nate Williams | Jun 25, 2000 9:41 pm | |
| Frank Mayhar | Jun 25, 2000 11:27 pm | |
| Frank Mayhar | Jun 25, 2000 11:31 pm | |
| Luoqi Chen | Jun 26, 2000 9:46 am | |
| Arun Sharma | Jun 26, 2000 9:47 am | |
| Jason Evans | Jun 26, 2000 11:06 am | |
| Matthew Dillon | Jun 26, 2000 12:26 pm | |
| Matthew Dillon | Jun 26, 2000 12:48 pm | |
| John Sconiers | Jun 26, 2000 12:56 pm | |
| Matthew Dillon | Jun 26, 2000 1:07 pm | |
| Luoqi Chen | Jun 26, 2000 1:13 pm | |
| Doug Rabson | Jun 26, 2000 1:26 pm | |
| Jason Evans | Jun 26, 2000 2:56 pm | |
| Jason Evans | Jun 26, 2000 3:14 pm | |
| Daniel Eischen | Jun 26, 2000 4:59 pm | |
| Luoqi Chen | Jun 26, 2000 7:14 pm | |
| Jason Evans | Jun 26, 2000 7:55 pm | |
| Joe Eykholt | Jun 26, 2000 8:09 pm | |
| Greg Lehey | Jun 27, 2000 8:00 pm | |
| Jason Evans | Jun 27, 2000 8:25 pm | |
| Daniel Eischen | Jun 27, 2000 8:26 pm | |
| Greg Lehey | Jun 27, 2000 9:59 pm | |
| Greg Lehey | Jun 27, 2000 10:11 pm | |
| Terry Lambert | Jun 28, 2000 4:15 pm | |
| Terry Lambert | Jun 28, 2000 4:18 pm | |
| Terry Lambert | Jun 28, 2000 4:37 pm | |
| Terry Lambert | Jun 28, 2000 4:51 pm | |
| Arun Sharma | Jun 28, 2000 9:43 pm | |
| Greg Lehey | Jul 2, 2000 7:15 pm | |
| Daniel Eischen | Jul 3, 2000 3:23 am | |
| Greg Lehey | Jul 3, 2000 3:30 am | |
| Jeroen C. van Gelderen | Jul 3, 2000 7:55 am | |
| Chuck Paterson | Jul 3, 2000 8:28 am | |
| Chuck Paterson | Jul 3, 2000 8:47 am | |
| Frank Mayhar | Jul 3, 2000 8:49 am | |
| Greg Lehey | Jul 3, 2000 4:08 pm | |
| David Scheidt | Jul 3, 2000 4:35 pm | |
| Joe Eykholt | Jul 3, 2000 4:47 pm | |
| Greg Lehey | Jul 3, 2000 4:52 pm | |
| Joe Eykholt | Jul 3, 2000 4:58 pm | |
| Greg Lehey | Jul 3, 2000 5:26 pm | |
| Joe Eykholt | Jul 3, 2000 5:41 pm | |
| Chuck Paterson | Jul 3, 2000 7:17 pm | |
| Daniel Eischen | Jul 3, 2000 7:25 pm | |
| Daniel Eischen | Jul 3, 2000 7:35 pm | |
| Greg Lehey | Jul 3, 2000 7:39 pm | |
| Daniel Eischen | Jul 3, 2000 7:41 pm | |
| Chuck Paterson | Jul 3, 2000 8:40 pm | |
| Alfred Perlstein | Jul 3, 2000 10:08 pm | |
| Greg Lehey | Jul 3, 2000 10:37 pm | |
| Peter Wemm | Jul 4, 2000 2:43 pm | |
| Greg Lehey | Jul 4, 2000 3:58 pm | |
| Peter Wemm | Jul 4, 2000 4:06 pm | |
| Terry Lambert | Jul 5, 2000 3:38 pm | |
| Terry Lambert | Jul 5, 2000 4:00 pm | |
| Terry Lambert | Jul 5, 2000 4:06 pm | |
| Terry Lambert | Jul 5, 2000 4:10 pm | |
| Alfred Perlstein | Jul 5, 2000 4:29 pm | |
| Terry Lambert | Jul 6, 2000 4:50 pm |
| Subject: | Re: SMP meeting summary | |
|---|---|---|
| From: | Luoqi Chen (luo...@watermarkgroup.com) | |
| Date: | Jun 26, 2000 1:13:02 pm | |
| List: | org.freebsd.freebsd-smp | |
On Mon, Jun 26, 2000 at 12:46:30PM -0400, Luoqi Chen wrote:
Compared with the use of tsleep(), mutexes have a number of advantages:
- Each mutex has its own wait (sleep) queue. When a process releases a mutex, it automatically schedules the next process waiting on the queue. This is more efficient than searching a possibly very long, linear sleep queue. It also avoids the flooding when multiple processes get scheduled, and most of them have to go back to sleep again.
What about processes of different priorities blocking for the same mutex? Would you do a linear search on the queue? or have the queue sorted by priority? or a FIFO queue is good enough?
Processes that block on a mutex are granted the lock in FIFO order, rather than priority order. In order to avoid priority inversion, the mutex wait queue implements priority lending.
Jason
Ok. I remember I have read somewhere that solaris 7 has given up the behavior of waking up only one thread after a mutex is released, now it wakes up all the blocking threads. It seems that the "thundering herd" problem is not serious after all if the lock granuity is high enough.
-lq
To Unsubscribe: send mail to majo...@FreeBSD.org with "unsubscribe freebsd-smp" in the body of the message