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| author | Simon Marlow <marlowsd@gmail.com> | 2010-03-29 14:44:56 +0000 |
|---|---|---|
| committer | Simon Marlow <marlowsd@gmail.com> | 2010-03-29 14:44:56 +0000 |
| commit | 5d52d9b64c21dcf77849866584744722f8121389 (patch) | |
| tree | 25aeafc9b761e73714c24ae414c0b1c41765c99f /rts/RetainerProfile.c | |
| parent | 79957d77c1bff767f1041d3fabdeb94d92a52878 (diff) | |
| download | haskell-5d52d9b64c21dcf77849866584744722f8121389.tar.gz | |
New implementation of BLACKHOLEs
This replaces the global blackhole_queue with a clever scheme that
enables us to queue up blocked threads on the closure that they are
blocked on, while still avoiding atomic instructions in the common
case.
Advantages:
- gets rid of a locked global data structure and some tricky GC code
(replacing it with some per-thread data structures and different
tricky GC code :)
- wakeups are more prompt: parallel/concurrent performance should
benefit. I haven't seen anything dramatic in the parallel
benchmarks so far, but a couple of threading benchmarks do improve
a bit.
- waking up a thread blocked on a blackhole is now O(1) (e.g. if
it is the target of throwTo).
- less sharing and better separation of Capabilities: communication
is done with messages, the data structures are strictly owned by a
Capability and cannot be modified except by sending messages.
- this change will utlimately enable us to do more intelligent
scheduling when threads block on each other. This is what started
off the whole thing, but it isn't done yet (#3838).
I'll be documenting all this on the wiki in due course.
Diffstat (limited to 'rts/RetainerProfile.c')
| -rw-r--r-- | rts/RetainerProfile.c | 9 |
1 files changed, 2 insertions, 7 deletions
diff --git a/rts/RetainerProfile.c b/rts/RetainerProfile.c index ba4d1465c8..b5db15a7b6 100644 --- a/rts/RetainerProfile.c +++ b/rts/RetainerProfile.c @@ -453,8 +453,6 @@ push( StgClosure *c, retainer c_child_r, StgClosure **first_child ) // no child, no SRT case CONSTR_0_1: case CONSTR_0_2: - case CAF_BLACKHOLE: - case BLACKHOLE: case ARR_WORDS: *first_child = NULL; return; @@ -470,6 +468,7 @@ push( StgClosure *c, retainer c_child_r, StgClosure **first_child ) case IND_PERM: case IND_OLDGEN_PERM: case IND_OLDGEN: + case BLACKHOLE: *first_child = ((StgInd *)c)->indirectee; return; case CONSTR_1_0: @@ -916,8 +915,6 @@ pop( StgClosure **c, StgClosure **cp, retainer *r ) // no child (fixed), no SRT case CONSTR_0_1: case CONSTR_0_2: - case CAF_BLACKHOLE: - case BLACKHOLE: case ARR_WORDS: // one child (fixed), no SRT case MUT_VAR_CLEAN: @@ -1059,13 +1056,11 @@ isRetainer( StgClosure *c ) case FUN_0_2: // partial applications case PAP: - // blackholes - case CAF_BLACKHOLE: - case BLACKHOLE: // indirection case IND_PERM: case IND_OLDGEN_PERM: case IND_OLDGEN: + case BLACKHOLE: // static objects case CONSTR_STATIC: case FUN_STATIC: |