Commit Graph

97 Commits

Author SHA1 Message Date
John Baldwin
4d70511ac3 Use pause() rather than tsleep() on stack variables and function pointers. 2007-02-27 17:23:29 +00:00
Julian Elischer
c6226eea4c Move the seting of the idle_mask bits to a place where they
can't be wrong.
Also use the IDLETD bit in the thread mask to test if its an idle thread
rather than doing a PCPU access.
2007-02-02 05:14:22 +00:00
Jeff Roberson
f0393f063a - Remove setrunqueue and replace it with direct calls to sched_add().
setrunqueue() was mostly empty.  The few asserts and thread state
   setting were moved to the individual schedulers.  sched_add() was
   chosen to displace it for naming consistency reasons.
 - Remove adjustrunqueue, it was 4 lines of code that was ifdef'd to be
   different on all three schedulers where it was only called in one place
   each.
 - Remove the long ifdef'd out remrunqueue code.
 - Remove the now redundant ts_state.  Inspect the thread state directly.
 - Don't set TSF_* flags from kern_switch.c, we were only doing this to
   support a feature in one scheduler.
 - Change sched_choose() to return a thread rather than a td_sched.  Also,
   rely on the schedulers to return the idlethread.  This simplifies the
   logic in choosethread().  Aside from the run queue links kern_switch.c
   mostly does not care about the contents of td_sched.

Discussed with:	julian

 - Move the idle thread loop into the per scheduler area.  ULE wants to
   do something different from the other schedulers.

Suggested by:	jhb

Tested on:	x86/amd64 sched_{4BSD, ULE, CORE}.
2007-01-23 08:46:51 +00:00
Robert Watson
2da78e3862 Prefer a more traditional spelling of inhibited in comments and panic
messages.
2006-12-31 15:56:04 +00:00
David Xu
34e1241b9d Fix typo, p_slptime should be td_slptime. 2006-12-24 01:52:27 +00:00
Julian Elischer
ad1e7d285a Threading cleanup.. part 2 of several.
Make part of John Birrell's KSE patch permanent..
Specifically, remove:
Any reference of the ksegrp structure. This feature was
never fully utilised and made things overly complicated.
All code in the scheduler that tried to make threaded programs
fair to unthreaded programs.  Libpthread processes will already
do this to some extent and libthr processes already disable it.

Also:
Since this makes such a big change to the scheduler(s), take the opportunity
to rename some structures and elements that had to be moved anyhow.
This makes the code a lot more readable.

The ULE scheduler compiles again but I have no idea if it works.

The 4bsd scheduler still reqires a little cleaning and some functions that now do
ALMOST nothing will go away, but I thought I'd do that as a separate commit.

Tested by David Xu, and Dan Eischen using libthr and libpthread.
2006-12-06 06:34:57 +00:00
Julian Elischer
de38cd9d8b whitespace fix only 2006-11-20 16:13:02 +00:00
David Xu
653385756c Fix a copy-paste bug in NON-KSE case. 2006-11-14 05:48:27 +00:00
David Xu
5a21514727 Unbreak userland priority inheriting in NO_KSE case. 2006-11-11 13:11:29 +00:00
John Birrell
8460a577a4 Make KSE a kernel option, turned on by default in all GENERIC
kernel configs except sun4v (which doesn't process signals properly
with KSE).

Reviewed by:	davidxu@
2006-10-26 21:42:22 +00:00
David Xu
3db720fdce Add user priority loaning code to support priority propagation for
1:1 threading's POSIX priority mutexes, the code is no-op unless
priority-aware umtx code is committed.
2006-08-25 06:12:53 +00:00
Maxim Konovalov
1f36c876a1 o Fix grammar in the comment, indent macros. No functional changes. 2006-07-02 20:53:52 +00:00
Maxim Konovalov
75d960eb2e o Remove rev. 1.57 leftover, not reached code. 2006-07-02 20:49:46 +00:00
David E. O'Brien
2e4db89cfc Fix building with GCC 4.2: define data types before referring to them. 2006-06-29 19:37:31 +00:00
David Xu
36ec198bd5 Add scheduler API sched_relinquish(), the API is used to implement
yield() and sched_yield() syscalls. Every scheduler has its own way
to relinquish cpu, the ULE and CORE schedulers have two internal run-
queues, a timesharing thread which calls yield() syscall should be
moved to inactive queue.
2006-06-15 06:37:39 +00:00
David Xu
b41f1452d9 Add scheduler CORE, the work I have done half a year ago, recent,
I picked it up again. The scheduler is forked from ULE, but the
algorithm to detect an interactive process is almost completely
different with ULE, it comes from Linux paper "Understanding the
Linux 2.6.8.1 CPU Scheduler", although I still use same word
"score" as a priority boost in ULE scheduler.

Briefly, the scheduler has following characteristic:
1. Timesharing process's nice value is seriously respected,
   timeslice and interaction detecting algorithm are based
   on nice value.
2. per-cpu scheduling queue and load balancing.
3. O(1) scheduling.
4. Some cpu affinity code in wakeup path.
5. Support POSIX SCHED_FIFO and SCHED_RR.
Unlike scheduler 4BSD and ULE which using fuzzy RQ_PPQ, the scheduler
uses 256 priority queues. Unlike ULE which using pull and push, the
scheduelr uses pull method, the main reason is to let relative idle
cpu do the work, but current the whole scheduler is protected by the
big sched_lock, so the benefit is not visible, it really can be worse
than nothing because all other cpu are locked out when we are doing
balancing work, which the 4BSD scheduelr does not have this problem.
The scheduler does not support hyperthreading very well, in fact,
the scheduler does not make the difference between physical CPU and
logical CPU, this should be improved in feature. The scheduler has
priority inversion problem on MP machine, it is not good for
realtime scheduling, it can cause realtime process starving.
As a result, it seems the MySQL super-smack runs better on my
Pentium-D machine when using libthr, despite on UP or SMP kernel.
2006-06-13 13:12:56 +00:00
David Xu
0ae716e5ee Make ke_rqindex unsigned. 2006-06-06 12:26:17 +00:00
John-Mark Gurney
5c06d111b8 back out for now... revert ccpu to being kern.ccpu... 2006-04-27 17:57:59 +00:00
John-Mark Gurney
c71ce6a445 move remaining sysctl into the kern.sched tree... 2006-04-26 19:42:38 +00:00
John Baldwin
0f180a7cce Change msleep() and tsleep() to not alter the calling thread's priority
if the specified priority is zero.  This avoids a race where the calling
thread could read a snapshot of it's current priority, then a different
thread could change the first thread's priority, then the original thread
would call sched_prio() inside msleep() undoing the change made by the
second thread.  I used a priority of zero as no thread that calls msleep()
or tsleep() should be specifying a priority of zero anyway.

The various places that passed 'curthread->td_priority' or some variant
as the priority now pass 0.
2006-04-17 18:20:38 +00:00
Peter Wemm
4da0d332f4 Move HWPMC_HOOKS into its own opt_hwpmc_hooks.h file. It doesn't merit
being in opt_global.h and forcing a global recompile when only a few files
reference it.

Approved by:  re
2005-06-24 00:16:57 +00:00
Stephan Uphoff
a3f2d84279 Lots of whitespace cleanup.
Fix for broken if condition.

Submitted by:	nate@
2005-06-09 19:43:08 +00:00
Stephan Uphoff
f3a0f87396 Fix some race conditions for pinned threads that may cause them to run
on the wrong CPU.

Add IPI support for preempting a thread on another CPU.

MFC after:3 weeks
2005-06-09 18:26:31 +00:00
Joseph Koshy
ebccf1e3a6 Bring a working snapshot of hwpmc(4), its associated libraries, userland utilities
and documentation into -CURRENT.

Bump FreeBSD_version.

Reviewed by:	alc, jhb (kernel changes)
2005-04-19 04:01:25 +00:00
Maxim Konovalov
f305048664 Fix a typo in the comment.
Noticed by:	Samy Al Bahra
2005-04-15 14:01:43 +00:00
Stephan Uphoff
779186434a Sprinkle some volatile magic and rearrange things a bit to avoid race
conditions in critical_exit now that it no longer blocks interrupts.

Reviewed by:	jhb
2005-04-08 03:37:53 +00:00
John Baldwin
f5c157d986 Rework the interface between priority propagation (lending) and the
schedulers a bit to ensure more correct handling of priorities and fewer
priority inversions:
- Add two functions to the sched(9) API to handle priority lending:
  sched_lend_prio() and sched_unlend_prio().  The turnstile code uses these
  functions to ask the scheduler to lend a thread a set priority and to
  tell the scheduler when it thinks it is ok for a thread to stop borrowing
  priority.  The unlend case is slightly complex in that the turnstile code
  tells the scheduler what the minimum priority of the thread needs to be
  to satisfy the requirements of any other threads blocked on locks owned
  by the thread in question.  The scheduler then decides where the thread
  can go back to normal mode (if it's normal priority is high enough to
  satisfy the pending lock requests) or it it should continue to use the
  priority specified to the sched_unlend_prio() call.  This involves adding
  a new per-thread flag TDF_BORROWING that replaces the ULE-only kse flag
  for priority elevation.
- Schedulers now refuse to lower the priority of a thread that is currently
  borrowing another therad's priority.
- If a scheduler changes the priority of a thread that is currently sitting
  on a turnstile, it will call a new function turnstile_adjust() to inform
  the turnstile code of the change.  This function resorts the thread on
  the priority list of the turnstile if needed, and if the thread ends up
  at the head of the list (due to having the highest priority) and its
  priority was raised, then it will propagate that new priority to the
  owner of the lock it is blocked on.

Some additional fixes specific to the 4BSD scheduler include:
- Common code for updating the priority of a thread when the user priority
  of its associated kse group has been consolidated in a new static
  function resetpriority_thread().  One change to this function is that
  it will now only adjust the priority of a thread if it already has a
  time sharing priority, thus preserving any boosts from a tsleep() until
  the thread returns to userland.  Also, resetpriority() no longer calls
  maybe_resched() on each thread in the group. Instead, the code calling
  resetpriority() is responsible for calling resetpriority_thread() on
  any threads that need to be updated.
- schedcpu() now uses resetpriority_thread() instead of just calling
  sched_prio() directly after it updates a kse group's user priority.
- sched_clock() now uses resetpriority_thread() rather than writing
  directly to td_priority.
- sched_nice() now updates all the priorities of the threads after the
  group priority has been adjusted.

Discussed with:	bde
Reviewed by:	ups, jeffr
Tested on:	4bsd, ule
Tested on:	i386, alpha, sparc64
2004-12-30 20:52:44 +00:00
Jeff Roberson
907bdbc288 - Wrap the thread count adjustment in sched_load_add() and sched_load_rem()
so that we may place some ktr entries nearby.
 - Define other KTR_SCHED tracepoints so that we may graph the operation
   of the scheduler.
2004-12-26 00:16:24 +00:00
Jeff Roberson
7842f65e7f - Garbage collect several unused members of struct kse and struce ksegrp.
As best as I can tell, some of these were never used.
2004-12-14 10:53:55 +00:00
Stephan Uphoff
5656474145 Propagate TDF_NEEDRESCHED to replacement thread in sched_switch().
Reviewed by:    julian, jhb (in October)
Approved by:    sam (mentor)
MFC after:      4 weeks
2004-12-07 18:17:24 +00:00
Julian Elischer
c20c691bed When preempting a thread, put it back on the HEAD of its run queue.
(Only really implemented in 4bsd)

MFC after:	4 days
2004-10-05 22:03:10 +00:00
Julian Elischer
d39063f20d Use some macros to trach available scheduler slots to allow
easier debugging.

MFC after:	4 days
2004-10-05 21:10:44 +00:00
Julian Elischer
14f0e2e9bf clean up thread runq accounting a bit.
MFC after:	3 days
2004-09-16 07:12:59 +00:00
Julian Elischer
b2578c6c06 Add some kasserts 2004-09-13 23:02:52 +00:00
Scott Long
1e7fad6b6a Revert the previous round of changes to td_pinned. The scheduler isn't
fully initialed when the pmap layer tries to call sched_pini() early in the
boot and results in an quick panic.  Use ke_pinned instead as was originally
done with Tor's patch.

Approved by: julian
2004-09-11 10:07:22 +00:00
Julian Elischer
5c854accc1 Make up my mind if cpu pinning is stored in the thread structure or the
scheduler specific extension to it. Put it in the extension as
the implimentation details of how the pinning is done needn't be visible
outside the scheduler.

Submitted by:	tegge  (of course!)   (with changes)
MFC after:	3 days
2004-09-10 22:28:33 +00:00
Julian Elischer
3389af30e8 Add some code to allow threads to nominat a sibling to run if theyu are going to sleep.
MFC after:	1 week
2004-09-10 21:04:38 +00:00
Julian Elischer
6a574b2afc Don't do IPIs on behalf of interrupt threads.
just punt straight on through to teh preemption code.

Make a KASSSERT out of a condition that can no longer occur.
MFC after:	1 week
2004-09-06 07:23:14 +00:00
Julian Elischer
0fe38d47b7 slight code cleanup
MFC after:	1 week
2004-09-05 23:23:58 +00:00
Julian Elischer
bce73aeddb turn on IPIs for 4bsd scheduler by default.
MFC after:	1 week
2004-09-05 02:19:53 +00:00
Julian Elischer
ed062c8d66 Refactor a bunch of scheduler code to give basically the same behaviour
but with slightly cleaned up interfaces.

The KSE structure has become the same as the "per thread scheduler
private data" structure. In order to not make the diffs too great
one is #defined as the other at this time.

The KSE (or td_sched) structure is  now allocated per thread and has no
allocation code of its own.

Concurrency for a KSEGRP is now kept track of via a simple pair of counters
rather than using KSE structures as tokens.

Since the KSE structure is different in each scheduler, kern_switch.c
is now included at the end of each scheduler. Nothing outside the
scheduler knows the contents of the KSE (aka td_sched) structure.

The fields in the ksegrp structure that are to do with the scheduler's
queueing mechanisms are now moved to the kg_sched structure.
(per ksegrp scheduler private data structure). In other words how the
scheduler queues and keeps track of threads is no-one's business except
the scheduler's. This should allow people to write experimental
schedulers with completely different internal structuring.

A scheduler call sched_set_concurrency(kg, N) has been added that
notifies teh scheduler that no more than N threads from that ksegrp
should be allowed to be on concurrently scheduled. This is also
used to enforce 'fainess' at this time so that a ksegrp with
10000 threads can not swamp a the run queue and force out a process
with 1 thread, since the current code will not set the concurrency above
NCPU, and both schedulers will not allow more than that many
onto the system run queue at a time. Each scheduler should eventualy develop
their own methods to do this now that they are effectively separated.

Rejig libthr's kernel interface to follow the same code paths as
linkse for scope system threads. This has slightly hurt libthr's performance
but I will work to recover as much of it as I can.

Thread exit code has been cleaned up greatly.
exit and exec code now transitions a process back to
'standard non-threaded mode' before taking the next step.
Reviewed by:	scottl, peter
MFC after:	1 week
2004-09-05 02:09:54 +00:00
Julian Elischer
00b0483d5c Don't declare a function we are not defining. 2004-09-03 09:19:49 +00:00
Julian Elischer
37c28a022b fix compile for UP 2004-09-03 09:15:10 +00:00
Julian Elischer
293968d8d3 ooops finish last commit.
moved the variables but not the declarations.
2004-09-03 08:19:31 +00:00
Julian Elischer
82a1dfc16d Move 4bsd specific experimental IP code into the 4bsd file.
Move the sysctls into kern.sched
2004-09-03 07:42:31 +00:00
Julian Elischer
6804a3ab6d Give the 4bsd scheduler the ability to wake up idle processors
when there is new work to be done.

MFC after:	5 days
2004-09-01 06:42:02 +00:00
Julian Elischer
2630e4c90c Give setrunqueue() and sched_add() more of a clue as to
where they are coming from and what is expected from them.

MFC after:	2 days
2004-09-01 02:11:28 +00:00
Julian Elischer
ad59c36ba1 diff reduction for upcoming patch. Use a macro that masks
some of the odd goings on with sub-structures, because they will
go away anyhow.
2004-08-22 05:21:41 +00:00
Julian Elischer
0f54f48225 Properly keep track of how many kses are on the system run queue(s). 2004-08-11 20:54:48 +00:00
Julian Elischer
732d95288a Increase the amount of data exported by KTR in the KTR_RUNQ setting.
This extra data is needed to really follow what is going on in the
threaded case.
2004-08-09 18:21:12 +00:00