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* Move `/includes` to `/rts/include`, sort per package betterJohn Ericson2021-08-091-330/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | In order to make the packages in this repo "reinstallable", we need to associate source code with a specific packages. Having a top level `/includes` dir that mixes concerns (which packages' includes?) gets in the way of this. To start, I have moved everything to `rts/`, which is mostly correct. There are a few things however that really don't belong in the rts (like the generated constants haskell type, `CodeGen.Platform.h`). Those needed to be manually adjusted. Things of note: - No symlinking for sake of windows, so we hard-link at configure time. - `CodeGen.Platform.h` no longer as `.hs` extension (in addition to being moved to `compiler/`) so as not to confuse anyone, since it is next to Haskell files. - Blanket `-Iincludes` is gone in both build systems, include paths now more strictly respect per-package dependencies. - `deriveConstants` has been taught to not require a `--target-os` flag when generating the platform-agnostic Haskell type. Make takes advantage of this, but Hadrian has yet to.
* Add code comments for StgInfoTable and StgStack structsDavid Eichmann2020-11-101-2/+14
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* winio: Add IOPort synchronization primitiveTamar Christina2020-07-151-0/+1
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* Changing Thread IDs from 32 bits to 64 bits.Roland Zumkeller2019-11-191-2/+2
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* NonMoving: Add summarizing Notewip/gc/docsBen Gamari2019-10-221-0/+3
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* rts: Shrink size of STACK's dirty and marking fieldsBen Gamari2019-10-201-2/+2
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* rts: Implement concurrent collection in the nonmoving collectorBen Gamari2019-10-201-1/+49
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This extends the non-moving collector to allow concurrent collection. The full design of the collector implemented here is described in detail in a technical note B. Gamari. "A Concurrent Garbage Collector For the Glasgow Haskell Compiler" (2018) This extension involves the introduction of a capability-local remembered set, known as the /update remembered set/, which tracks objects which may no longer be visible to the collector due to mutation. To maintain this remembered set we introduce a write barrier on mutations which is enabled while a concurrent mark is underway. The update remembered set representation is similar to that of the nonmoving mark queue, being a chunked array of `MarkEntry`s. Each `Capability` maintains a single accumulator chunk, which it flushed when it (a) is filled, or (b) when the nonmoving collector enters its post-mark synchronization phase. While the write barrier touches a significant amount of code it is conceptually straightforward: the mutator must ensure that the referee of any pointer it overwrites is added to the update remembered set. However, there are a few details: * In the case of objects with a dirty flag (e.g. `MVar`s) we can exploit the fact that only the *first* mutation requires a write barrier. * Weak references, as usual, complicate things. In particular, we must ensure that the referee of a weak object is marked if dereferenced by the mutator. For this we (unfortunately) must introduce a read barrier, as described in Note [Concurrent read barrier on deRefWeak#] (in `NonMovingMark.c`). * Stable names are also a bit tricky as described in Note [Sweeping stable names in the concurrent collector] (`NonMovingSweep.c`). We take quite some pains to ensure that the high thread count often seen in parallel Haskell applications doesn't affect pause times. To this end we allow thread stacks to be marked either by the thread itself (when it is executed or stack-underflows) or the concurrent mark thread (if the thread owning the stack is never scheduled). There is a non-trivial handshake to ensure that this happens without racing which is described in Note [StgStack dirtiness flags and concurrent marking]. Co-Authored-by: Ömer Sinan Ağacan <omer@well-typed.com>
* rts: Give stack flags proper macrosBen Gamari2019-10-181-0/+5
| | | | | This were previously quite unclear and will change a bit under the non-moving collector so let's clear this up now.
* Prefer #if defined to #ifdefBen Gamari2017-04-281-3/+3
| | | | Our new CPP linter enforces this.
* 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
* RTS: delete BlockedOnGA* + dead codeThomas Miedema2016-04-291-10/+1
| | | | | | | | Some old stuff related to the PAR way. Reviewed by: austin, simonmar Differential Revision: https://phabricator.haskell.org/D2137
* Remove obsolete/redundant FLEXIBLE_ARRAY macroHerbert Valerio Riedel2016-04-181-1/+1
| | | | | | | | | | | | | | | This macro is doubly redundant, first off all, ancient GCCs prior to version 3.0 are not supported anymore, but more importantly, we require a ISO C99 compliant compiler, so we can use the proper ISO C syntax without worrying about compatibility. Reviewers: austin, bgamari Reviewed By: bgamari Subscribers: carter, thomie Differential Revision: https://phabricator.haskell.org/D2121
* rts: drop unused global 'blackhole_queue'Sergei Trofimovich2016-02-271-1/+1
| | | | | | | | | | | | | | | | | | | | | | 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
* fix bus errors on SPARC caused by unalignment access to alloc_limit (fixes ↵Karel Gardas2015-02-231-0/+3
| | | | | | | | | | #10043) Reviewers: austin, simonmar Subscribers: thomie Differential Revision: https://phabricator.haskell.org/D657
* Per-thread allocation counters and limitsSimon Marlow2014-11-121-9/+22
| | | | | | | | This reverts commit f0fcc41d755876a1b02d1c7c79f57515059f6417. New changes: now works on 32-bit platforms too. I added some basic support for 64-bit subtraction and comparison operations to the x86 NCG.
* Revert "Rename _closure to _static_closure, apply naming consistently."Edward Z. Yang2014-10-201-1/+1
| | | | | | | This reverts commit 35672072b4091d6f0031417bc160c568f22d0469. Conflicts: compiler/main/DriverPipeline.hs
* Rename _closure to _static_closure, apply naming consistently.Edward Z. Yang2014-10-011-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Summary: In preparation for indirecting all references to closures, we rename _closure to _static_closure to ensure any old code will get an undefined symbol error. In order to reference a closure foobar_closure (which is now undefined), you should instead use STATIC_CLOSURE(foobar). For convenience, a number of these old identifiers are macro'd. Across C-- and C (Windows and otherwise), there were differing conventions on whether or not foobar_closure or &foobar_closure was the address of the closure. Now, all foobar_closure references are addresses, and no & is necessary. CHARLIKE/INTLIKE were not changed, simply alpha-renamed. Part of remove HEAP_ALLOCED patch set (#8199) Depends on D265 Signed-off-by: Edward Z. Yang <ezyang@mit.edu> Test Plan: validate Reviewers: simonmar, austin Subscribers: simonmar, ezyang, carter, thomie Differential Revision: https://phabricator.haskell.org/D267 GHC Trac Issues: #8199
* [ci skip] includes: detabify/dewhitespace rts/storage/TSO.hAustin Seipp2014-08-201-13/+13
| | | | Signed-off-by: Austin Seipp <austin@well-typed.com>
* Revert "Per-thread allocation counters and limits"Simon Marlow2014-05-041-22/+9
| | | | | | | | Problems were found on 32-bit platforms, I'll commit again when I have a fix. This reverts the following commits: 54b31f744848da872c7c6366dea840748e01b5cf b0534f78a73f972e279eed4447a5687bd6a8308e
* Per-thread allocation counters and limitsSimon Marlow2014-05-021-9/+22
| | | | | | | | | | | | | | | | | | | | | | | This tracks the amount of memory allocation by each thread in a counter stored in the TSO. Optionally, when the counter drops below zero (it counts down), the thread can be sent an asynchronous exception: AllocationLimitExceeded. When this happens, given a small additional limit so that it can handle the exception. See documentation in GHC.Conc for more details. Allocation limits are similar to timeouts, but - timeouts use real time, not CPU time. Allocation limits do not count anything while the thread is blocked or in foreign code. - timeouts don't re-trigger if the thread catches the exception, allocation limits do. - timeouts can catch non-allocating loops, if you use -fno-omit-yields. This doesn't work for allocation limits. I couldn't measure any impact on benchmarks with these changes, even for nofib/smp.
* fix warningsSimon Marlow2013-01-301-1/+0
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* STM: Only wake up onceBen Gamari2013-01-301-1/+3
| | | | | | | | | | | Previously, threads blocked on an STM retry would be sent a wakeup message each time an unpark was requested. This could result in the accumulation of a large number of wake-up messages, which would slow wake-up once the sleeping thread is finally scheduled. Here, we introduce a new closure type, STM_AWOKEN, which marks a TSO which has been sent a wake-up message, allowing us to send only one wakeup.
* Improve the handling of threadDelay in the non-threaded RTSSimon Marlow2012-04-111-1/+1
| | | | | | | Firstly, we were rounding up too much, such that the smallest delay was 20ms. Secondly, there is no need to use millisecond resolution on a 64-bit machine where we have room in the TSO to use the normal nanosecond resolution that we use elsewhere in the RTS.
* Rename the CCCS field of StgTSO so as not to conflict with the CCCS ↵Simon Marlow2012-01-051-1/+1
| | | | | | pseudo-register Needed by #5357
* Time handling overhaulSimon Marlow2011-11-251-0/+6
| | | | | | | | | | | | | | | | | | | | | Terminology cleanup: the type "Ticks" has been renamed "Time", which is an StgWord64 in units of TIME_RESOLUTION (currently nanoseconds). The terminology "tick" is now used consistently to mean the interval between timer signals. The ticker now always ticks in realtime (actually CLOCK_MONOTONIC if we have it). Before it used CPU time in the non-threaded RTS and realtime in the threaded RTS, but I've discovered that the CPU timer has terrible resolution (at least on Linux) and isn't much use for profiling. So now we always use realtime. This should also fix The default tick interval is now 10ms, except when profiling where we drop it to 1ms. This gives more accurate profiles without affecting runtime too much (<1%). Lots of cleanups - the resolution of Time is now in one place only (Rts.h) rather than having calculations that depend on the resolution scattered all over the RTS. I hope I found them all.
* Implement stack chunks and separate TSO/STACK objectsSimon Marlow2010-12-151-41/+41
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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.
* Change the representation of the MVar blocked queueSimon Marlow2010-04-011-1/+0
| | | | | | | | | | | | | | | | | | | | | The list of threads blocked on an MVar is now represented as a list of separately allocated objects rather than being linked through the TSOs themselves. This lets us remove a TSO from the list in O(1) time rather than O(n) time, by marking the list object. Removing this linear component fixes some pathalogical performance cases where many threads were blocked on an MVar and became unreachable simultaneously (nofib/smp/threads007), or when sending an asynchronous exception to a TSO in a long list of thread blocked on an MVar. MVar performance has actually improved by a few percent as a result of this change, slightly to my surprise. This is the final cleanup in the sequence, which let me remove the old way of waking up threads (unblockOne(), MSG_WAKEUP) in favour of the new way (tryWakeupThread and MSG_TRY_WAKEUP, which is idempotent). It is now the case that only the Capability that owns a TSO may modify its state (well, almost), and this simplifies various things. More of the RTS is based on message-passing between Capabilities now.
* Move a thread to the front of the run queue when another thread blocks on itSimon Marlow2010-03-291-0/+2
| | | | | | | 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 Marlow2010-03-291-1/+25
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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.
* Use message-passing to implement throwTo in the RTSSimon Marlow2010-03-111-9/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | 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 Marlow2010-03-091-1/+1
| | | | | | | | | | | | | | | 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).
* Fix #3429: a tricky race conditionSimon Marlow2009-08-181-1/+19
| | | | | | | | | | | | | | | | | | There were two bugs, and had it not been for the first one we would not have noticed the second one, so this is quite fortunate. The first bug is in stg_unblockAsyncExceptionszh_ret, when we found a pending exception to raise, but don't end up raising it, there was a missing adjustment to the stack pointer. The second bug was that this case was actually happening at all: it ought to be incredibly rare, because the pending exception thread would have to be killed between us finding it and attempting to raise the exception. This made me suspicious. It turned out that there was a race condition on the tso->flags field; multiple threads were updating this bitmask field non-atomically (one of the bits is the dirty-bit for the generational GC). The fix is to move the dirty bit into its own field of the TSO, making the TSO one word larger (sadly).
* RTS tidyup sweep, first phaseSimon Marlow2009-08-021-0/+206
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.