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* Support R_X86_64_TLSGD relocation on FreeBSDViktor Dukhovni2021-04-225-4/+170
| | | | | | | | | | | | | | | The FreeBSD C <ctype.h> header supports per-thread locales by exporting a static inline function that references the `_ThreadRuneLocale` thread-local variable. This means that object files that use e.g. isdigit(3) end up with TLSGD(19) relocations, and would not load into ghci or the language server. Here we add support for this type of relocation, for now just on FreeBSD, and only for external references to thread-specifics defined in already loaded dynamic modules (primarily libc.so). This is sufficient to resolve the <ctype.h> issues. Runtime linking of ".o" files which *define* new thread-specific variables would be noticeably more difficult, as this would likely require new rtld APIs.
* rts: Fix usage of pthread_setname_npBen Gamari2021-04-051-2/+6
| | | | | | | Previously we used this non-portable function unconditionally, breaking FreeBSD. Fixes #19637.
* Fix copy+pasto in Sanity.cMatthew Pickering2021-04-021-1/+1
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* [armv7] arm32 needs symbols!Moritz Angermann2021-03-292-3/+5
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* [aarch64-darwin] be very careful of warnings.Moritz Angermann2021-03-291-0/+1
| | | | | | | So we did *not* have the stgCallocBytes prototype, and subsequently the C compiler defaulted to `int` as a return value. Thus generating sxtw instructions for the return value of stgCalloBytes to produce the expected void *.
* [rts] cast return value to struct.Moritz Angermann2021-03-291-1/+1
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* [linker] no munmap if either agument is invalid.Moritz Angermann2021-03-291-1/+4
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* [linker/aarch64-elf] support section symbols for GOT relocationMoritz Angermann2021-03-291-1/+7
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* [linker] align prototype with implementation signature.Moritz Angermann2021-03-291-2/+2
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* [linker] SymbolExtras are only used on PPC and X86Moritz Angermann2021-03-292-5/+4
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* [linker] Additional FALLTHROUGH decorations.Moritz Angermann2021-03-291-0/+2
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* Allocate Adjustors and mark them readable in two stepsMoritz Angermann2021-03-297-6/+46
| | | | | | | | | This drops allocateExec for darwin, and replaces it with a alloc, write, mark executable strategy instead. This prevents us from trying to allocate an executable range and then write to it, which X^W will prohibit on darwin. This will *only* work if we can use mmap.
* [macho] improved linker with proper plt supportMoritz Angermann2021-03-298-97/+311
| | | | This is a pre-requisite for making aarch64-darwin work.
* rts: Fix joinOSThread on WindowsBen Gamari2021-03-271-1/+6
| | | | | Previously we were treating the thread ID as a HANDLE, but it is not. We must first OpenThread.
* rts: Use long-path-aware statBen Gamari2021-03-231-2/+5
| | | | | | | | Previously `pathstat` relied on msvcrt's `stat` implementation, which was not long-path-aware. It should rather be defined in terms of the `stat` implementation provided by `utils/fs`. Fixes #19541.
* [elf/aarch64] Fall Through decorationMoritz Angermann2021-03-211-4/+4
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* Add error information to osCommitMemory on failure.Moritz Angermann2021-03-201-1/+1
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* Generate GHCi bytecode from STG instead of Core and support unboxedLuite Stegeman2021-03-205-23/+466
| | | | | | tuples and sums. fixes #1257
* Make traceHeapEventInfo an init eventMatthew Pickering2021-03-141-6/+18
| | | | This means it will be reposted everytime the eventlog is started.
* Ignore breakpoint for a specified number of iterations. (#19157)Roland Senn2021-03-101-5/+8
| | | | | | | | | | | | | | | | * Implement new debugger command `:ignore` to set an `ignore count` for a specified breakpoint. * Allow new optional parameter on `:continue` command to set an `ignore count` for the current breakpoint. * In the Interpreter replace the current `Word8` BreakArray with an `Int` array. * Change semantics of values in `BreakArray` to: n < 0 : Breakpoint is disabled. n == 0 : Breakpoint is enabled. n > 0 : Breakpoint is enabled, but ignore next `n` iterations. * Rewrite `:enable`/`:disable` processing as a special case of `:ignore`. * Remove references to `BreakArray` from `ghc/UI.hs`.
* rts: Gradually return retained memory to the OSMatthew Pickering2021-03-104-18/+104
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Related to #19381 #19359 #14702 After a spike in memory usage we have been conservative about returning allocated blocks to the OS in case we are still allocating a lot and would end up just reallocating them. The result of this was that up to 4 * live_bytes of blocks would be retained once they were allocated even if memory usage ended up a lot lower. For a heap of size ~1.5G, this would result in OS memory reporting 6G which is both misleading and worrying for users. In long-lived server applications this results in consistent high memory usage when the live data size is much more reasonable (for example ghcide) Therefore we have a new (2021) strategy which starts by retaining up to 4 * live_bytes of blocks before gradually returning uneeded memory back to the OS on subsequent major GCs which are NOT caused by a heap overflow. Each major GC which is NOT caused by heap overflow increases the consec_idle_gcs counter and the amount of memory which is retained is inversely proportional to this number. By default the excess memory retained is oldGenFactor (controlled by -F) / 2 ^ (consec_idle_gcs * returnDecayFactor) On a major GC caused by a heap overflow, the `consec_idle_gcs` variable is reset to 0 (as we could continue to allocate more, so retaining all the memory might make sense). Therefore setting bigger values for `-Fd` makes the rate at which memory is returned slower. Smaller values make it get returned faster. Setting `-Fd0` disables the memory return completely, which is the behaviour of older GHC versions. The default is `-Fd4` which results in the following scaling: > mapM print [(x, 1/ (2**(x / 4))) | x <- [1 :: Double ..20]] (1.0,0.8408964152537146) (2.0,0.7071067811865475) (3.0,0.5946035575013605) (4.0,0.5) (5.0,0.4204482076268573) (6.0,0.35355339059327373) (7.0,0.29730177875068026) (8.0,0.25) (9.0,0.21022410381342865) (10.0,0.17677669529663687) (11.0,0.14865088937534013) (12.0,0.125) (13.0,0.10511205190671433) (14.0,8.838834764831843e-2) (15.0,7.432544468767006e-2) (16.0,6.25e-2) (17.0,5.255602595335716e-2) (18.0,4.4194173824159216e-2) (19.0,3.716272234383503e-2) (20.0,3.125e-2) So after 13 consecutive GCs only 0.1 of the maximum memory used will be retained. Further to this decay factor, the amount of memory we attempt to retain is also influenced by the GC strategy for the oldest generation. If we are using a copying strategy then we will need at least 2 * live_bytes for copying to take place, so we always keep that much. If using compacting or nonmoving then we need a lower number, so we just retain at least `1.2 * live_bytes` for some protection. In future we might want to make this behaviour more aggressive, some relevant literature is > Ulan Degenbaev, Jochen Eisinger, Manfred Ernst, Ross McIlroy, and Hannes Payer. 2016. Idle time garbage collection scheduling. SIGPLAN Not. 51, 6 (June 2016), 570–583. DOI:https://doi.org/10.1145/2980983.2908106 which describes the "memory reducer" in the V8 javascript engine which on an idle collection immediately returns as much memory as possible.
* eventlog: Repost initialisation events when eventlog restartsMatthew Pickering2021-03-085-9/+93
| | | | | | | | | | | | | | | | | | If startEventlog is called after the program has already started running then quite a few useful events are missing from the eventlog because they are only posted when the program starts. This patch adds a mechanism to declare that an event should be reposted everytime the startEventlog function is called. Now in EventLog.c there is a global list of functions called `eventlog_header_funcs` which stores a list of functions which should be called everytime the eventlog starts. When calling `postInitEvent`, the event will not only be immediately posted to the eventlog but also added to the global list. When startEventLog is called, the list is traversed and the events reposted.
* rts: Use a separate free block list for allocatePinnedMatthew Pickering2021-03-084-15/+157
| | | | | | | | | | | The way in which allocatePinned took blocks out of the nursery was leading to horrible fragmentation in some workloads. The strategy now is that a separate free block list is reserved for each capability and blocks are taken from there. When it's empty the global SM lock is taken and a fresh block of size PINNED_EMPTY_SIZE is allocated. Fixes #19481
* eventlog: Add BLOCKS_SIZE eventMatthew Pickering2021-03-084-1/+19
| | | | | | | | | | | | | The BLOCKS_SIZE event reports the size of the currently allocated blocks in bytes. It is like the HEAP_SIZE event, but reports about the blocks rather than megablocks. You can work out the current heap fragmentation by looking at the difference between HEAP_SIZE and BLOCKS_SIZE. Fixes #19357
* eventlog: Add MEM_RETURN event to give information about fragmentationMatthew Pickering2021-03-088-3/+81
| | | | | | | | | | | | | | See #19357 The event reports the * Current number of megablocks allocated * The number that the RTS thinks it needs * The number is managed to return to the OS When current > need then the difference is returned to the OS, the successful number of returned mblocks is reported by 'returned'. In a fragmented heap current > need but returned < current - need.
* Implement riscv64 LLVM backendAndreas Schwab2021-03-054-2/+152
| | | | This enables a registerised build for the riscv64 architecture.
* rts: Make markLiveObject thread-safeBen Gamari2021-03-042-3/+9
| | | | | | | | markLiveObject is called by GC worker threads and therefore must be thread-safe. This was a rather egregious oversight which the testsuite missed. (cherry picked from commit fe28a062e47bd914a6879f2d01ff268983c075ad)
* Add whereFrom and whereFrom# primopMatthew Pickering2021-03-032-0/+10
| | | | | | | | | | The `whereFrom` function provides a Haskell interface for using the information created by `-finfo-table-map`. Given a Haskell value, the info table address will be passed to the `lookupIPE` function in order to attempt to find the source location information for that particular closure. At the moment it's not possible to distinguish the absense of the map and a failed lookup.
* Add -finfo-table-map which maps info tables to source positionsMatthew Pickering2021-03-039-0/+170
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This new flag embeds a lookup table from the address of an info table to information about that info table. The main interface for consulting the map is the `lookupIPE` C function > InfoProvEnt * lookupIPE(StgInfoTable *info) The `InfoProvEnt` has the following structure: > typedef struct InfoProv_{ > char * table_name; > char * closure_desc; > char * ty_desc; > char * label; > char * module; > char * srcloc; > } InfoProv; > > typedef struct InfoProvEnt_ { > StgInfoTable * info; > InfoProv prov; > struct InfoProvEnt_ *link; > } InfoProvEnt; The source positions are approximated in a similar way to the source positions for DWARF debugging information. They are only approximate but in our experience provide a good enough hint about where the problem might be. It is therefore recommended to use this flag in conjunction with `-g<n>` for more accurate locations. The lookup table is also emitted into the eventlog when it is available as it is intended to be used with the `-hi` profiling mode. Using this flag will significantly increase the size of the resulting object file but only by a factor of 2-3x in our experience.
* Profiling by info table mode (-hi)Matthew Pickering2021-03-033-0/+19
| | | | | | | | This profiling mode creates bands by the address of the info table for each closure. This provides a much more fine-grained profiling output than any of the other profiling modes. The `-hi` profiling mode does not require a profiling build.
* Profiling: Allow heap profiling to be controlled dynamically.Matthew Pickering2021-03-036-11/+60
| | | | | | | | | | This patch exposes three new functions in `GHC.Profiling` which allow heap profiling to be enabled and disabled dynamically. 1. startHeapProfTimer - Starts heap profiling with the given RTS options 2. stopHeapProfTimer - Stops heap profiling 3. requestHeapCensus - Perform a heap census on the next context switch, regardless of whether the timer is enabled or not.
* eventlog: Fix various racesBen Gamari2021-03-024-19/+136
| | | | | | | | | | | | | | | Previously the eventlog infrastructure had a couple of races that could pop up when using the startEventLog/endEventLog interfaces. In particular, stopping and then later restarting logging could result in data preceding the eventlog header, breaking the integrity of the stream. To fix this we rework the invariants regarding the eventlog and generally tighten up the concurrency control surrounding starting and stopping of logging. We also fix an unrelated bug, wherein log events from disabled capabilities could end up never flushed.
* rts/eventlog: Flush MainCapability buffer in non-threaded RTSBen Gamari2021-03-011-0/+2
| | | | | | | Previously flushEventLog failed to flush anything but the global event buffer in the non-threaded RTS. Fixes #19436.
* rts/eventlog: Ensure that all capability buffers are flushedBen Gamari2021-03-012-1/+2
| | | | | | | | | | | The previous approach performed the flush in yieldCapability. However, as pointed out in #19435, this is wrong as it idle capabilities will not go through this codepath. The fix is simple: undo the optimisation, flushing in `flushEventLog` by calling `flushAllCapsEventsBufs` after acquiring all capabilities. Fixes #19435.
* Remove the -xt heap profiling optionMatthew Pickering2021-02-272-28/+3
| | | | | | | It should be left to tooling to perform the filtering to remove these specific closure types from the profile if desired. Fixes #16795
* rts: Introduce --eventlog-flush-interval flagBen Gamari2021-02-272-0/+32
| | | | | | | This introduces a flag, --eventlog-flush-interval, which can be used to set an upper bound on the amount of time for which an eventlog event will remain enqueued. This can be useful in real-time monitoring settings.
* Move absentError into ghc-prim.Andreas Klebinger2021-02-263-1/+8
| | | | | | | | | | | | When using -fdicts-strict we generate references to absentError while compiling ghc-prim. However we always load ghc-prim before base so this caused linker errors. We simply solve this by moving absentError into ghc-prim. This does mean it's now a panic instead of an exception which can no longer be caught. But given that it should only be thrown if there is a compiler error that seems acceptable, and in fact we already do this for absentSumFieldError which has similar constraints.
* linker: Fix atexit handlers on PETamar Christina2021-02-222-3/+5
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* Do not cas on slowpath of SpinLock unnecessarilyDylan Yudaken2021-02-221-3/+35
| | | | This is a well known technique to reduce inter-CPU bus traffic while waiting for the lock by reducing the number of writes.
* rts: Add generic block traversal function, listAllBlocksMatthew Pickering2021-02-181-0/+36
| | | | | | | | | This function is exposed in the RtsAPI.h so that external users have a blessed way to traverse all the different `bdescr`s which are known by the RTS. The main motivation is to use this function in ghc-debug but avoid having to expose the internal structure of a Capability in the API.
* rts: TraverseHeap: Update resetStaticObjectForProfiling docsDaniel Gröber2021-02-171-22/+18
| | | | | | | | | | | | | | | | | | | | | | | | Simon's concern in the old comment, specifically: So all of the calls to traverseMaybeInitClosureData() here are initialising retainer sets with the wrong flip. Is actually exactly what the code was intended to do. It makes the closure data valid, then at the beginning of the traversal the flip bit is flipped resetting all closures across the heap to invalid. Now it used to be that the profiling code using the traversal has it's own sense of valid vs. invalid beyond what the traversal code does and indeed the retainer profiler still does this, there a getClosureData of NULL is considered an invalid retainer set. So in effect there wasn't any difference in invalidating closure data rather than just resetting it to a valid zero, which might be what confused Simon at the time. As the code is now it actually uses the value of the valid/invalid bit in the form of the 'first_visit' argument to the 'visit' callback so there is a difference.
* rts: TraverseHeap: Fix failed to inline warningsDaniel Gröber2021-02-171-1/+1
| | | | GCC warns that varadic functions simply cannot be inlined.
* rts: ProfHeap: Move definitions for Census to new headerDaniel Gröber2021-02-172-50/+77
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* rts: ProfHeap: Merge some redundant ifdefsDaniel Gröber2021-02-171-10/+1
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* rts: TraverseHeap: Allow visit_cb to be NULLDaniel Gröber2021-02-171-2/+4
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* rts: TraverseHeap: Add a basic testDaniel Gröber2021-02-174-0/+224
| | | | | For now this just tests that the order of the callbacks is what we expect for a couple of synthetic heap graphs.
* rts: TraverseHeap: Move stackElement to headerDaniel Gröber2021-02-172-69/+64
| | | | | | | The point of this is to let user code call traversePushClosure directly instead of going through traversePushRoot. This in turn allows specifying a stackElement to be used when the traversal returns from a top-level (root) closure.
* rts: TraverseHeap: Make "flip" bit flip into it's own functionDaniel Gröber2021-02-173-11/+25
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* rts: TraverseHeap: Move "flip" bit into traverseState structDaniel Gröber2021-02-176-57/+67
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* rts: TraverseHeap: Make trav. data macros into functionsDaniel Gröber2021-02-174-22/+30
| | | | | This allows the global 'flip' variable not to be exported. This allows a future commit to also make it part of the traversalState struct.