2 Commits

Author	SHA1	Message	Date
FICTURE7	69093cf2d6	Optimize LSRA (#2563) ... * Optimize `TryAllocateRegWithtoutSpill` a bit * Add a fast path for when all registers are live. * Do not query `GetOverlapPosition` if the register is already in use (i.e: free position is 0). * Do not allocate child split list if not parent * Turn `LiveRange` into a reference struct `LiveRange` is now a reference wrapping struct like `Operand` and `Operation`. It has also been changed into a singly linked-list. In micro-benchmarks traversing the linked-list was faster than binary search on `List<T>`. Even for quite large input sizes (e.g: 1,000,000), surprisingly. Could be because the code gen for traversing the linked-list is much much cleaner and there is no virtual dispatch happening when checking if intervals overlaps. * Turn `LiveInterval` into an iterator The LSRA allocates in forward order and never inspect previous `LiveInterval` once they are expired. Something similar can be done for the `LiveRange`s within the `LiveInterval`s themselves. The `LiveInterval` is turned into a iterator which expires `LiveRange` within it. The iterator is moved forward along with interval walking code, i.e: AllocateInterval(context, interval, cIndex). * Remove `LinearScanAllocator.Sources` Local methods are less susceptible to do allocations than lambdas. * Optimize `GetOverlapPosition(interval)` a bit Time complexity should be in O(n+m) instead of O(nm) now. * Optimize `NumberLocals` a bit Use the same idea as in `HybridAllocator` to store the visited state in the MSB of the Operand's value instead of using a `HashSet<T>`. * Optimize `InsertSplitCopies` a bit Avoid allocating a redundant `CopyResolver`. * Optimize `InsertSplitCopiesAtEdges` a bit Avoid redundant allocations of `CopyResolver`. * Use stack allocation for `freePositions` Avoid redundant computations. * Add `UseList` Replace `SortedIntegerList` with an even more specialized data structure. It allocates memory on the arena allocators and does not require copying use positions when splitting it. * Turn `LiveInterval` into a reference struct `LiveInterval` is now a reference wrapping struct like `Operand` and `Operation`. The rationale behind turning this in a reference wrapping struct is because a `LiveInterval` is associated with each local variable, and these intervals may themselves be split further. I've seen translations having up to 8000 local variables. To make the `LiveInterval` unmanaged, a new data structure called `LiveIntervalList` was added to store child splits. This differs from `SortedList<,>` because it can contain intervals with the same start position. Really wished we got some more of C++ template in C#. :^( * Optimize `GetChildSplit` a bit No need to inspect the remaining ranges if we've reached a range which starts after position, since the split list is ordered. * Optimize `CopyResolver` a bit Lazily allocate the fill, spill and parallel copy structures since most of the time only one of them is needed. * Optimize `BitMap.Enumerator` a bit Marking `MoveNext` as `AggressiveInlining` allows RyuJIT to promote the `Enumerator` struct into registers completely, reducing load/store code a lot since it does not have to store the struct on the stack for ABI purposes. * Use stack allocation for `use/blockedPositions` * Optimize `AllocateWithSpill` a bit * Address feedback * Make `LiveInterval.AddRange(,)` more conservative Produces no diff against master, but just for good measure.	2021-10-08 18:15:44 -03:00
FICTURE7	22b2cb39af	Reduce JIT GC allocations (#2515) ... * Turn `MemoryOperand` into a struct * Remove `IntrinsicOperation` * Remove `PhiNode` * Remove `Node` * Turn `Operand` into a struct * Turn `Operation` into a struct * Clean up pool management methods * Add `Arena` allocator * Move `OperationHelper` to `Operation.Factory` * Move `OperandHelper` to `Operand.Factory` * Optimize `Operation` a bit * Fix `Arena` initialization * Rename `NativeList<T>` to `ArenaList<T>` * Reduce `Operand` size from 88 to 56 bytes * Reduce `Operation` size from 56 to 40 bytes * Add optimistic interning of Register & Constant operands * Optimize `RegisterUsage` pass a bit * Optimize `RemoveUnusedNodes` pass a bit Iterating in reverse-order allows killing dependency chains in a single pass. * Fix PPTC symbols * Optimize `BasicBlock` a bit Reduce allocations from `_successor` & `DominanceFrontiers` * Fix `Operation` resize * Make `Arena` expandable Change the arena allocator to be expandable by allocating in pages, with some of them being pooled. Currently 32 pages are pooled. An LRU removal mechanism should probably be added to it. Apparently MHR can allocate bitmaps large enough to exceed the 16MB limit for the type. * Move `Arena` & `ArenaList` to `Common` * Remove `ThreadStaticPool` & co * Add `PhiOperation` * Reduce `Operand` size from 56 from 48 bytes * Add linear-probing to `Operand` intern table * Optimize `HybridAllocator` a bit * Add `Allocators` class * Tune `ArenaAllocator` sizes * Add page removal mechanism to `ArenaAllocator` Remove pages which have not been used for more than 5s after each reset. I am on fence if this would be better using a Gen2 callback object like the one in System.Buffers.ArrayPool<T>, to trim the pool. Because right now if a large translation happens, the pages will be freed only after a reset. This reset may not happen for a while because no new translation is hit, but the arena base sizes are rather small. * Fix `OOM` when allocating larger than page size in `ArenaAllocator` Tweak resizing mechanism for Operand.Uses and Assignemnts. * Optimize `Optimizer` a bit * Optimize `Operand.Add<T>/Remove<T>` a bit * Clean up `PreAllocator` * Fix phi insertion order Reduce codegen diffs. * Fix code alignment * Use new heuristics for degree of parallelism * Suppress warnings * Address gdkchan's feedback Renamed `GetValue()` to `GetValueUnsafe()` to make it more clear that `Operand.Value` should usually not be modified directly. * Add fast path to `ArenaAllocator` * Assembly for `ArenaAllocator.Allocate(ulong)`: .L0: mov rax, [rcx+0x18] lea r8, [rax+rdx] cmp r8, [rcx+0x10] ja short .L2 .L1: mov rdx, [rcx+8] add rax, [rdx+8] mov [rcx+0x18], r8 ret .L2: jmp ArenaAllocator.AllocateSlow(UInt64) A few variable/field had to be changed to ulong so that RyuJIT avoids emitting zero-extends. * Implement a new heuristic to free pooled pages. If an arena is used often, it is more likely that its pages will be needed, so the pages are kept for longer (e.g: during PPTC rebuild or burst sof compilations). If is not used often, then it is more likely that its pages will not be needed (e.g: after PPTC rebuild or bursts of compilations). * Address riperiperi's feedback * Use `EqualityComparer<T>` in `IntrusiveList<T>` Avoids a potential GC hole in `Equals(T, T)`.	2021-08-17 15:08:34 -03:00