Add a port of mimalloc, a fast and scalable multithreaded allocator

ChangeLog.md

@@ -20,6 +20,8 @@ See docs/process.md for more on how version tagging works.
 
 3.1.50 (in development)
 -----------------------
+- Add a port of mimalloc, a fast and scalable multithreaded allocator. To use
+  it, build with `-sMALLOC=mimalloc`. (#20651)
 - When compiling, Emscripten will now invoke `clang` or `clang++` depending only
   on whether `emcc` or `em++` was run.  Previously it would determine which to
   run based on individual file extensions.  One side effect of this is that you

embuilder.py

@@ -56,6 +56,8 @@
     'libemmalloc-memvalidate',
     'libemmalloc-verbose',
     'libemmalloc-memvalidate-verbose',
+    'libmimalloc',
+    'libmimalloc-mt',
     'libGL',
     'libhtml5',
     'libsockets',

site/source/docs/optimizing/Optimizing-Code.rst

@@ -221,6 +221,15 @@ Enable :ref:`debugging-EMCC_DEBUG` to output files for each compilation phase, i
 
 .. _optimizing-code-unsafe-optimisations:
 
+Allocation
+----------
+
+The default ``malloc/free`` implementation used is ``dlmalloc``. You can also
+pick ``emmalloc`` (``-sMALLOC=emmalloc``) which is smaller but less fast, or
+``mimalloc`` (``-sMALLOC=mimalloc``) which is larger but scales better in a
+multithreaded application with contention on ``malloc/free`` (see
+:ref:`Allocator_performance`).
+
 Unsafe optimizations
 ====================
 

site/source/docs/porting/pthreads.rst

@@ -148,6 +148,24 @@ The Emscripten implementation for the pthreads API should follow the POSIX stand
 
 Also note that when compiling code that uses pthreads, an additional JavaScript file ``NAME.worker.js`` is generated alongside the output .js file (where ``NAME`` is the basename of the main file being emitted). That file must be deployed with the rest of the generated code files. By default, ``NAME.worker.js`` will be loaded relative to the main HTML page URL. If it is desirable to load the file from a different location e.g. in a CDN environment, then one can define the ``Module.locateFile(filename)`` function in the main HTML ``Module`` object to return the URL of the target location of the ``NAME.worker.js`` entry point. If this function is not defined in ``Module``, then the default location relative to the main HTML file is used.
 
+.. _Allocator_performance:
+
+Allocator performance
+=====================
+
+The default system allocator in Emscripten, ``dlmalloc``, is very efficient in a
+single-threaded program, but it has a single global lock which means if there is
+contention on ``malloc`` then you can see overhead. You can use
+`mimalloc <https://github.com/microsoft/mimalloc>`_
+instead by using ``-sMALLOC=mimalloc``, which is a more sophisticated allocator
+tuned for multithreaded performance. ``mimalloc`` has separate allocation
+contexts on each thread, allowing performance to scale a lot better under
+``malloc/free`` contention.
+
+Note that ``mimalloc`` is larger in code size than ``dlmalloc``, and also uses
+more memory at runtime (so you may need to adjust ``INITIAL_MEMORY`` to a higher
+value), so there are tradeoffs here.
+
 Running code and tests
 ======================
 

src/settings.js

@@ -108,6 +108,9 @@ var STACK_SIZE = 64*1024;
 //  * emmalloc-verbose - use emmalloc with assertions + verbose logging.
 //  * emmalloc-memvalidate-verbose - use emmalloc with assertions + heap
 //                                   consistency checking + verbose logging.
+//  * mimalloc - a powerful mulithreaded allocator. This is recommended in
+//               large applications that have malloc() contention, but it is
+//               larger and uses more memory.
 //  * none     - no malloc() implementation is provided, but you must implement
 //               malloc() and free() yourself.
 // dlmalloc is necessary for split memory and other special modes, and will be

system/lib/mimalloc/LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2018-2021 Microsoft Corporation, Daan Leijen
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

system/lib/mimalloc/README.emscripten

@@ -0,0 +1,7 @@
+
+This contains mimalloc 4e50d6714d471b72b2285e25a3df6c92db944593 with
+Emscripten backend additions.
+
+Origin: https://github.com/microsoft/mimalloc
+
+For the Emscripten port design see src/prim/emscripten/prim.c

system/lib/mimalloc/include/mimalloc-new-delete.h

@@ -0,0 +1,66 @@
+/* ----------------------------------------------------------------------------
+Copyright (c) 2018-2020 Microsoft Research, Daan Leijen
+This is free software; you can redistribute it and/or modify it under the
+terms of the MIT license. A copy of the license can be found in the file
+"LICENSE" at the root of this distribution.
+-----------------------------------------------------------------------------*/
+#pragma once
+#ifndef MIMALLOC_NEW_DELETE_H
+#define MIMALLOC_NEW_DELETE_H
+
+// ----------------------------------------------------------------------------
+// This header provides convenient overrides for the new and
+// delete operations in C++.
+//
+// This header should be included in only one source file!
+//
+// On Windows, or when linking dynamically with mimalloc, these
+// can be more performant than the standard new-delete operations.
+// See <https://en.cppreference.com/w/cpp/memory/new/operator_new>
+// ---------------------------------------------------------------------------
+#if defined(__cplusplus)
+  #include <new>
+  #include <mimalloc.h>
+
+  #if defined(_MSC_VER) && defined(_Ret_notnull_) && defined(_Post_writable_byte_size_)
+  // stay consistent with VCRT definitions
+  #define mi_decl_new(n)          mi_decl_nodiscard mi_decl_restrict _Ret_notnull_ _Post_writable_byte_size_(n)
+  #define mi_decl_new_nothrow(n)  mi_decl_nodiscard mi_decl_restrict _Ret_maybenull_ _Success_(return != NULL) _Post_writable_byte_size_(n)
+  #else
+  #define mi_decl_new(n)          mi_decl_nodiscard mi_decl_restrict
+  #define mi_decl_new_nothrow(n)  mi_decl_nodiscard mi_decl_restrict
+  #endif
+
+  void operator delete(void* p) noexcept              { mi_free(p); };
+  void operator delete[](void* p) noexcept            { mi_free(p); };
+
+  void operator delete  (void* p, const std::nothrow_t&) noexcept { mi_free(p); }
+  void operator delete[](void* p, const std::nothrow_t&) noexcept { mi_free(p); }
+
+  mi_decl_new(n) void* operator new(std::size_t n) noexcept(false) { return mi_new(n); }
+  mi_decl_new(n) void* operator new[](std::size_t n) noexcept(false) { return mi_new(n); }
+
+  mi_decl_new_nothrow(n) void* operator new  (std::size_t n, const std::nothrow_t& tag) noexcept { (void)(tag); return mi_new_nothrow(n); }
+  mi_decl_new_nothrow(n) void* operator new[](std::size_t n, const std::nothrow_t& tag) noexcept { (void)(tag); return mi_new_nothrow(n); }
+
+  #if (__cplusplus >= 201402L || _MSC_VER >= 1916)
+  void operator delete  (void* p, std::size_t n) noexcept { mi_free_size(p,n); };
+  void operator delete[](void* p, std::size_t n) noexcept { mi_free_size(p,n); };
+  #endif
+
+  #if (__cplusplus > 201402L || defined(__cpp_aligned_new))
+  void operator delete  (void* p, std::align_val_t al) noexcept { mi_free_aligned(p, static_cast<size_t>(al)); }
+  void operator delete[](void* p, std::align_val_t al) noexcept { mi_free_aligned(p, static_cast<size_t>(al)); }
+  void operator delete  (void* p, std::size_t n, std::align_val_t al) noexcept { mi_free_size_aligned(p, n, static_cast<size_t>(al)); };
+  void operator delete[](void* p, std::size_t n, std::align_val_t al) noexcept { mi_free_size_aligned(p, n, static_cast<size_t>(al)); };
+  void operator delete  (void* p, std::align_val_t al, const std::nothrow_t&) noexcept { mi_free_aligned(p, static_cast<size_t>(al)); }
+  void operator delete[](void* p, std::align_val_t al, const std::nothrow_t&) noexcept { mi_free_aligned(p, static_cast<size_t>(al)); }
+
+  void* operator new  (std::size_t n, std::align_val_t al) noexcept(false) { return mi_new_aligned(n, static_cast<size_t>(al)); }
+  void* operator new[](std::size_t n, std::align_val_t al) noexcept(false) { return mi_new_aligned(n, static_cast<size_t>(al)); }
+  void* operator new  (std::size_t n, std::align_val_t al, const std::nothrow_t&) noexcept { return mi_new_aligned_nothrow(n, static_cast<size_t>(al)); }
+  void* operator new[](std::size_t n, std::align_val_t al, const std::nothrow_t&) noexcept { return mi_new_aligned_nothrow(n, static_cast<size_t>(al)); }
+  #endif
+#endif
+
+#endif // MIMALLOC_NEW_DELETE_H

system/lib/mimalloc/include/mimalloc-override.h

@@ -0,0 +1,67 @@
+/* ----------------------------------------------------------------------------
+Copyright (c) 2018-2020 Microsoft Research, Daan Leijen
+This is free software; you can redistribute it and/or modify it under the
+terms of the MIT license. A copy of the license can be found in the file
+"LICENSE" at the root of this distribution.
+-----------------------------------------------------------------------------*/
+#pragma once
+#ifndef MIMALLOC_OVERRIDE_H
+#define MIMALLOC_OVERRIDE_H
+
+/* ----------------------------------------------------------------------------
+This header can be used to statically redirect malloc/free and new/delete
+to the mimalloc variants. This can be useful if one can include this file on
+each source file in a project (but be careful when using external code to
+not accidentally mix pointers from different allocators).
+-----------------------------------------------------------------------------*/
+
+#include <mimalloc.h>
+
+// Standard C allocation
+#define malloc(n)               mi_malloc(n)
+#define calloc(n,c)             mi_calloc(n,c)
+#define realloc(p,n)            mi_realloc(p,n)
+#define free(p)                 mi_free(p)
+
+#define strdup(s)               mi_strdup(s)
+#define strndup(s,n)              mi_strndup(s,n)
+#define realpath(f,n)           mi_realpath(f,n)
+
+// Microsoft extensions
+#define _expand(p,n)            mi_expand(p,n)
+#define _msize(p)               mi_usable_size(p)
+#define _recalloc(p,n,c)        mi_recalloc(p,n,c)
+
+#define _strdup(s)              mi_strdup(s)
+#define _strndup(s,n)           mi_strndup(s,n)
+#define _wcsdup(s)              (wchar_t*)mi_wcsdup((const unsigned short*)(s))
+#define _mbsdup(s)              mi_mbsdup(s)
+#define _dupenv_s(b,n,v)        mi_dupenv_s(b,n,v)
+#define _wdupenv_s(b,n,v)       mi_wdupenv_s((unsigned short*)(b),n,(const unsigned short*)(v))
+
+// Various Posix and Unix variants
+#define reallocf(p,n)           mi_reallocf(p,n)
+#define malloc_size(p)          mi_usable_size(p)
+#define malloc_usable_size(p)   mi_usable_size(p)
+#define cfree(p)                mi_free(p)
+
+#define valloc(n)               mi_valloc(n)
+#define pvalloc(n)              mi_pvalloc(n)
+#define reallocarray(p,s,n)     mi_reallocarray(p,s,n)
+#define reallocarr(p,s,n)       mi_reallocarr(p,s,n)
+#define memalign(a,n)           mi_memalign(a,n)
+#define aligned_alloc(a,n)      mi_aligned_alloc(a,n)
+#define posix_memalign(p,a,n)   mi_posix_memalign(p,a,n)
+#define _posix_memalign(p,a,n)  mi_posix_memalign(p,a,n)
+
+// Microsoft aligned variants
+#define _aligned_malloc(n,a)                  mi_malloc_aligned(n,a)
+#define _aligned_realloc(p,n,a)               mi_realloc_aligned(p,n,a)
+#define _aligned_recalloc(p,s,n,a)            mi_aligned_recalloc(p,s,n,a)
+#define _aligned_msize(p,a,o)                 mi_usable_size(p)
+#define _aligned_free(p)                      mi_free(p)
+#define _aligned_offset_malloc(n,a,o)         mi_malloc_aligned_at(n,a,o)
+#define _aligned_offset_realloc(p,n,a,o)      mi_realloc_aligned_at(p,n,a,o)
+#define _aligned_offset_recalloc(p,s,n,a,o)   mi_recalloc_aligned_at(p,s,n,a,o)
+
+#endif // MIMALLOC_OVERRIDE_H