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* rts: Fix typo in commentNiklas Hambüchen2017-09-191-1/+1
| | | | | | | | | | Reviewers: bgamari, austin, erikd, simonmar Reviewed By: bgamari Subscribers: rwbarton, thomie Differential Revision: https://phabricator.haskell.org/D3958
* cpp: Use #pragma once instead of #ifndef guardsBen Gamari2017-04-231-4/+1
| | | | | | | | | | | | | | This both says what we mean and silences a bunch of spurious CPP linting warnings. This pragma is supported by all CPP implementations which we support. Reviewers: austin, erikd, simonmar, hvr Reviewed By: simonmar Subscribers: rwbarton, thomie Differential Revision: https://phabricator.haskell.org/D3482
* Use C99's boolBen Gamari2016-11-291-5/+5
| | | | | | | | | | | | Test Plan: Validate on lots of platforms Reviewers: erikd, simonmar, austin Reviewed By: erikd, simonmar Subscribers: michalt, thomie Differential Revision: https://phabricator.haskell.org/D2699
* Track the lengths of the thread queuesSimon Marlow2016-08-031-10/+5
| | | | | | | | | | | | | | | Summary: Knowing the length of the run queue in O(1) time is useful: for example we don't have to traverse the run queue to know how many threads we have to migrate in schedulePushWork(). Test Plan: validate Reviewers: ezyang, erikd, bgamari, austin Subscribers: thomie Differential Revision: https://phabricator.haskell.org/D2437
* Refactor comments about shutdownSimon Marlow2016-04-101-3/+2
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* rts: drop unused global 'blackhole_queue'Sergei Trofimovich2016-02-271-1/+0
| | | | | | | | | | | | | | | | | | | | | | Commit 5d52d9b64c21dcf77849866584744722f8121389 removed global 'blackhole_queue' in favour of new mechanism: when TSO hits blackhole TSO blocks waiting for 'MessgaeBlackhole' delivery. Patch removed unused global and updates stale comments. Noticed by Yuras Shumovich. Signed-off-by: Sergei Trofimovich <siarheit@google.com> Test Plan: build test Reviewers: simonmar, austin, Yuras, bgamari Reviewed By: Yuras, bgamari Subscribers: thomie Differential Revision: https://phabricator.haskell.org/D1953
* rts: mark 'removeFromRunQueue' as staticSergei Trofimovich2016-02-071-2/+1
| | | | | | | | Noticed by uselex.rb: removeFromRunQueue: [R]: exported from: ./rts/dist/build/Schedule.o Signed-off-by: Sergei Trofimovich <siarheit@google.com>
* Remove comments and flag for GranSimThomas Miedema2015-03-191-2/+0
| | | | | | | | | The GranSim code was removed in dd56e9ab and 297b05a9 in 2009, and perhaps other commits I couldn't find. Reviewed By: austin Differential Revision: https://phabricator.haskell.org/D737
* [skip ci] rts: Detabify Schedule.hAustin Seipp2014-10-211-12/+11
| | | | Signed-off-by: Austin Seipp <austin@well-typed.com>
* Revert "rts: add Emacs 'Local Variables' to every .c file"Simon Marlow2014-09-291-8/+0
| | | | This reverts commit 39b5c1cbd8950755de400933cecca7b8deb4ffcd.
* rts: add Emacs 'Local Variables' to every .c fileAustin Seipp2014-07-281-0/+8
| | | | | | | | This will hopefully help ensure some basic consistency in the forward by overriding buffer variables. In particular, it sets the wrap length, the offset to 4, and turns off tabs. Signed-off-by: Austin Seipp <austin@well-typed.com>
* Schedule.h: Fix path of include file in commentBen Gamari2013-01-301-1/+1
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* Better abstraction over run queues.Edward Z. Yang2013-01-161-1/+24
| | | | | | | | | This adds some new functions: peekRunQueue, promoteInRunQueue, singletonRunQueue and truncateRunQueue which help abstract away manual linked list manipulation, making it easier to swap in a new queue implementation. Signed-off-by: Edward Z. Yang <ezyang@mit.edu>
* Another overhaul of the recent_activity / idle GC handling (#5991)Simon Marlow2012-09-241-5/+23
| | | | | | | | | | | | | | | Improvements: - we now turn off the timer signal in the non-threaded RTS after idleGCDelay. This should make the xmonad users on #5991 happy. - we now turn off the timer signal after idleGCDelay even if the idle GC is disabled with +RTS -I0. - we now do *not* turn off the timer when profiling. - more comments to explain the meaning of the various ACTIVITY_* values
* Do not emit the THREAD_RUNNABLE event; it has no useful semantic contentSimon Marlow2011-12-131-1/+0
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* Refactoring and tidy upSimon Marlow2011-04-111-0/+1
| | | | | | | | | | | | This is a port of some of the changes from my private local-GC branch (which is still in darcs, I haven't converted it to git yet). There are a couple of small functional differences in the GC stats: first, per-thread GC timings should now be more accurate, and secondly we now report average and maximum pause times. e.g. from minimax +RTS -N8 -s: Tot time (elapsed) Avg pause Max pause Gen 0 2755 colls, 2754 par 13.16s 0.93s 0.0003s 0.0150s Gen 1 769 colls, 769 par 3.71s 0.26s 0.0003s 0.0059s
* Implement stack chunks and separate TSO/STACK objectsSimon Marlow2010-12-151-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch makes two changes to the way stacks are managed: 1. The stack is now stored in a separate object from the TSO. This means that it is easier to replace the stack object for a thread when the stack overflows or underflows; we don't have to leave behind the old TSO as an indirection any more. Consequently, we can remove ThreadRelocated and deRefTSO(), which were a pain. This is obviously the right thing, but the last time I tried to do it it made performance worse. This time I seem to have cracked it. 2. Stacks are now represented as a chain of chunks, rather than a single monolithic object. The big advantage here is that individual chunks are marked clean or dirty according to whether they contain pointers to the young generation, and the GC can avoid traversing clean stack chunks during a young-generation collection. This means that programs with deep stacks will see a big saving in GC overhead when using the default GC settings. A secondary advantage is that there is much less copying involved as the stack grows. Programs that quickly grow a deep stack will see big improvements. In some ways the implementation is simpler, as nothing special needs to be done to reclaim stack as the stack shrinks (the GC just recovers the dead stack chunks). On the other hand, we have to manage stack underflow between chunks, so there's a new stack frame (UNDERFLOW_FRAME), and we now have separate TSO and STACK objects. The total amount of code is probably about the same as before. There are new RTS flags: -ki<size> Sets the initial thread stack size (default 1k) Egs: -ki4k -ki2m -kc<size> Sets the stack chunk size (default 32k) -kb<size> Sets the stack chunk buffer size (default 1k) -ki was previously called just -k, and the old name is still accepted for backwards compatibility. These new options are documented.
* Fix the symbol visibility pragmasSimon Marlow2010-06-171-2/+2
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* Fix bug in popRunQueueSimon Marlow2010-04-061-1/+3
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* Move a thread to the front of the run queue when another thread blocks on itSimon Marlow2010-03-291-0/+9
| | | | | | | This fixes #3838, and was made possible by the new BLACKHOLE infrastructure. To allow reording of the run queue I had to make it doubly-linked, which entails some extra trickiness with regard to GC write barriers and suchlike.
* New implementation of BLACKHOLEsSimon Marlow2010-03-291-9/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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.
* Fix warnings (allow pushOnRunQueue() to not be inlined)Simon Marlow2010-04-011-1/+4
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* Use message-passing to implement throwTo in the RTSSimon Marlow2010-03-111-28/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | This replaces some complicated locking schemes with message-passing in the implementation of throwTo. The benefits are - previously it was impossible to guarantee that a throwTo from a thread running on one CPU to a thread running on another CPU would be noticed, and we had to rely on the GC to pick up these forgotten exceptions. This no longer happens. - the locking regime is simpler (though the code is about the same size) - threads can be unblocked from a blocked_exceptions queue without having to traverse the whole queue now. It's a rare case, but replaces an O(n) operation with an O(1). - generally we move in the direction of sharing less between Capabilities (aka HECs), which will become important with other changes we have planned. Also in this patch I replaced several STM-specific closure types with a generic MUT_PRIM closure type, which allowed a lot of code in the GC and other places to go away, hence the line-count reduction. The message-passing changes resulted in about a net zero line-count difference.
* Split part of the Task struct into a separate struct InCallSimon Marlow2010-03-091-9/+2
| | | | | | | | | | | | | | | The idea is that this leaves Tasks and OSThread in one-to-one correspondence. The part of a Task that represents a call into Haskell from C is split into a separate struct InCall, pointed to by the Task and the TSO bound to it. A given OSThread/Task thus always uses the same mutex and condition variable, rather than getting a new one for each callback. Conceptually it is simpler, although there are more types and indirections in a few places now. This improves callback performance by removing some of the locks that we had to take when making in-calls. Now we also keep the current Task in a thread-local variable if supported by the OS and gcc (currently only Linux).
* Expose all EventLog events as DTrace probesManuel M T Chakravarty2009-12-121-1/+1
| | | | | | | | | | | | | | - Defines a DTrace provider, called 'HaskellEvent', that provides a probe for every event of the eventlog framework. - In contrast to the original eventlog, the DTrace probes are available in all flavours of the runtime system (DTrace probes have virtually no overhead if not enabled); when -DTRACING is defined both the regular event log as well as DTrace probes can be used. - Currently, Mac OS X only. User-space DTrace probes are implemented differently on Mac OS X than in the original DTrace implementation. Nevertheless, it shouldn't be too hard to enable these probes on other platforms, too. - Documentation is at http://hackage.haskell.org/trac/ghc/wiki/DTrace
* Make appendToRunQueue EXTERN_INLINE rather than INLINE_HEADERSimon Marlow2009-10-081-1/+4
| | | | Fixes compilation with gcc 4.4
* Omit visibility pragmas on Windows (fixes warnings/validate failures)Simon Marlow2009-09-091-2/+2
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* Unify event logging and debug tracing.Simon Marlow2009-08-291-2/+2
| | | | | | | | | | | | | | | | | | | - tracing facilities are now enabled with -DTRACING, and -DDEBUG additionally enables debug-tracing. -DEVENTLOG has been removed. - -debug now implies -eventlog - events can be printed to stderr instead of being sent to the binary .eventlog file by adding +RTS -v (which is implied by the +RTS -Dx options). - -Dx debug messages can be sent to the binary .eventlog file by adding +RTS -l. This should help debugging by reducing the impact of debug tracing on execution time. - Various debug messages that duplicated the information in events have been removed.
* Declare RTS-private prototypes with __attribute__((visibility("hidden")))Simon Marlow2009-08-051-0/+4
| | | | | | | | | | This has no effect with static libraries, but when the RTS is in a shared library it does two things: - it prevents the function from being exposed by the shared library - internal calls to the function can use the faster non-PLT calls, because the function cannot be overriden at link time.
* RTS tidyup sweep, first phaseSimon Marlow2009-08-021-41/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The first phase of this tidyup is focussed on the header files, and in particular making sure we are exposinng publicly exactly what we need to, and no more. - Rts.h now includes everything that the RTS exposes publicly, rather than a random subset of it. - Most of the public header files have moved into subdirectories, and many of them have been renamed. But clients should not need to include any of the other headers directly, just #include the main public headers: Rts.h, HsFFI.h, RtsAPI.h. - All the headers needed for via-C compilation have moved into the stg subdirectory, which is self-contained. Most of the headers for the rest of the RTS APIs have moved into the rts subdirectory. - I left MachDeps.h where it is, because it is so widely used in Haskell code. - I left a deprecated stub for RtsFlags.h in place. The flag structures are now exposed by Rts.h. - Various internal APIs are no longer exposed by public header files. - Various bits of dead code and declarations have been removed - More gcc warnings are turned on, and the RTS code is more warning-clean. - More source files #include "PosixSource.h", and hence only use standard POSIX (1003.1c-1995) interfaces. There is a lot more tidying up still to do, this is just the first pass. I also intend to standardise the names for external RTS APIs (e.g use the rts_ prefix consistently), and declare the internal APIs as hidden for shared libraries.
* Remove old GUM/GranSim codeSimon Marlow2009-06-021-23/+0
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* Add fast event loggingSimon Marlow2009-03-171-2/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | Generate binary log files from the RTS containing a log of runtime events with timestamps. The log file can be visualised in various ways, for investigating runtime behaviour and debugging performance problems. See for example the forthcoming ThreadScope viewer. New GHC option: -eventlog (link-time option) Enables event logging. +RTS -l (runtime option) Generates <prog>.eventlog with the binary event information. This replaces some of the tracing machinery we already had in the RTS: e.g. +RTS -vg for GC tracing (we should do this using the new event logging instead). Event logging has almost no runtime cost when it isn't enabled, though in the future we might add more fine-grained events and this might change; hence having a link-time option and compiling a separate version of the RTS for event logging. There's a small runtime cost for enabling event-logging, for most programs it shouldn't make much difference. (Todo: docs)
* Fix #2592: do an orderly shutdown when the heap is exhaustedSimon Marlow2008-12-091-0/+2
| | | | | | Really we should be raising an exception in this case, but that's tricky (see comments). At least now we shut down the runtime correctly rather than just exiting.
* Fix an extremely subtle deadlock bug on x86_64Simon Marlow2008-11-131-2/+2
| | | | | | | | | The recent_activity flag was an unsigned int, but we sometimes do a 64-bit xchg() on it, which overwrites the next word in memory. This happened to contain the sched_state flag, which is used to control the orderly shutdown of the system. If the xchg() happened during shutdown, the scheduler would get confused and deadlock. Don't you just love C?
* Move the context_switch flag into the CapabilitySimon Marlow2008-09-191-5/+0
| | | | | Fixes a long-standing bug that could in some cases cause sub-optimal scheduling behaviour.
* Use OSThreadProcAttr for workerStartIan Lynagh2008-09-111-1/+3
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* Fix race condition in wakeupThreadOnCapability() (#2574)Simon Marlow2008-09-091-5/+10
| | | | | | | | | | | wakeupThreadOnCapbility() is used to signal another capability that there is a thread waiting to be added to its run queue. It adds the thread to the (locked) wakeup queue on the remote capability. In order to do this, it has to modify the TSO's link field, which has a write barrier. The write barrier might put the TSO on the mutable list, and the bug was that it was using the mutable list of the *target* capability, which we do not have exclusive access to. We should be using the current Capabilty's mutable list in this case.
* Don't look at all the threads before each GC.Simon Marlow2008-04-161-0/+1
| | | | | | | | | | | We were looking at all the threads for 2 reasons: 1. to catch transactions that might be looping as a result of seeing an inconsistent view of memory. 2. to catch threads with blocked exceptions that are themselves blocked. For (1) we now check for this case whenever a thread yields, and for (2) we catch these threads in the GC itself and send the exceptions after GC (see performPendingThrowTos).
* Don't traverse the entire list of threads on every GC (phase 1)Simon Marlow2008-04-161-5/+0
| | | | | | Instead of keeping a single list of all threads, keep one per step and only look at the threads belonging to steps that we are collecting.
* Add a write barrier to the TSO link field (#1589)Simon Marlow2008-04-161-15/+9
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* move GetRoots() to GC.cSimon Marlow2007-10-301-9/+0
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* hs_exit()/shutdownHaskell(): wait for outstanding foreign calls to complete ↵Simon Marlow2007-07-241-1/+1
| | | | | | | | | | | | | | | | before returning This is pertinent to #1177. When shutting down a DLL, we need to be sure that there are no OS threads that can return to the code that we are about to unload, and previously the threaded RTS was unsafe in this respect. When exiting a standalone program we don't have to be quite so paranoid: all the code will disappear at the same time as any running threads. Happily exiting a program happens via a different path: shutdownHaskellAndExit(). If we're about to exit(), then there's no need to wait for foreign calls to complete.
* Add freeScheduler/freeTaskManager and call it later than exitSchedulerIan Lynagh2006-12-111-0/+1
| | | | | | | | | We were freeing the tasks in exitScheduler (stopTaskManager) before exitStorage (stat_exit), but the latter needs to walk down the list printing stats. Resulted in segfaults with commands like ghc -v0 -e main q.hs -H32m -H32m +RTS -Sstderr (where q.hs is trivial), but very sensitive to exact commandline and libc version or something.
* Split GC.c, and move storage manager into sm/ directorySimon Marlow2006-10-241-10/+10
| | | | | | | | | | | | | | | | | In preparation for parallel GC, split up the monolithic GC.c file into smaller parts. Also in this patch (and difficult to separate, unfortunatley): - Don't include Stable.h in Rts.h, instead just include it where necessary. - consistently use STATIC_INLINE in source files, and INLINE_HEADER in header files. STATIC_INLINE is now turned off when DEBUG is on, to make debugging easier. - The GC no longer takes the get_roots function as an argument. We weren't making use of this generalisation.
* Asynchronous exception support for SMPSimon Marlow2006-06-161-22/+1
| | | | | | | | | | | | | | | | | This patch makes throwTo work with -threaded, and also refactors large parts of the concurrency support in the RTS to clean things up. We have some new files: RaiseAsync.{c,h} asynchronous exception support Threads.{c,h} general threading-related utils Some of the contents of these new files used to be in Schedule.c, which is smaller and cleaner as a result of the split. Asynchronous exception support in the presence of multiple running Haskell threads is rather tricky. In fact, to my annoyance there are still one or two bugs to track down, but the majority of the tests run now.
* fix possible ^C problemsSimon Marlow2006-06-081-0/+6
| | | | | | | Calling prodAllCapabilities() from interruptStgRts() was wrong, for the same reasons that we stopped doing it in handle_tick(). We now use the same mechanism (send a byte down the pipe to the IO manager thread), but abstract it in a wakeUpRts() function in the scheduler.
* New tracing interfaceSimon Marlow2006-06-081-5/+0
| | | | | | | | A simple interface for generating trace messages with timestamps and thread IDs attached to them. Most debugging output goes through this interface now, so it is straightforward to get timestamped debugging traces with +RTS -vt. Also, we plan to use this to generate parallelism profiles from the trace output.
* Remove unnecessary SCHED_INTERRUPTED scheduler stateSimon Marlow2006-06-071-2/+1
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* Reorganisation of the source treeSimon Marlow2006-04-071-0/+332
Most of the other users of the fptools build system have migrated to Cabal, and with the move to darcs we can now flatten the source tree without losing history, so here goes. The main change is that the ghc/ subdir is gone, and most of what it contained is now at the top level. The build system now makes no pretense at being multi-project, it is just the GHC build system. No doubt this will break many things, and there will be a period of instability while we fix the dependencies. A straightforward build should work, but I haven't yet fixed binary/source distributions. Changes to the Building Guide will follow, too.
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