Firefox 3 came with a new allocator: jemalloc
.
I have heard at several places that this new allocator is better. The top Google results don\'t gave any
There is one interesting source: the C-source itself: https://dxr.mozilla.org/mozilla-central/source/memory/build/mozjemalloc.cpp (old)
In the beginning, a short summary describes how it works roughly.
// This allocator implementation is designed to provide scalable performance
// for multi-threaded programs on multi-processor systems. The following
// features are included for this purpose:
//
// + Multiple arenas are used if there are multiple CPUs, which reduces lock
// contention and cache sloshing.
//
// + Cache line sharing between arenas is avoided for internal data
// structures.
//
// + Memory is managed in chunks and runs (chunks can be split into runs),
// rather than as individual pages. This provides a constant-time
// mechanism for associating allocations with particular arenas.
//
// Allocation requests are rounded up to the nearest size class, and no record
// of the original request size is maintained. Allocations are broken into
// categories according to size class. Assuming runtime defaults, 4 kB pages
// and a 16 byte quantum on a 32-bit system, the size classes in each category
// are as follows:
//
// |=====================================|
// | Category | Subcategory | Size |
// |=====================================|
// | Small | Tiny | 4 |
// | | | 8 |
// | |----------------+---------|
// | | Quantum-spaced | 16 |
// | | | 32 |
// | | | 48 |
// | | | ... |
// | | | 480 |
// | | | 496 |
// | | | 512 |
// | |----------------+---------|
// | | Sub-page | 1 kB |
// | | | 2 kB |
// |=====================================|
// | Large | 4 kB |
// | | 8 kB |
// | | 12 kB |
// | | ... |
// | | 1012 kB |
// | | 1016 kB |
// | | 1020 kB |
// |=====================================|
// | Huge | 1 MB |
// | | 2 MB |
// | | 3 MB |
// | | ... |
// |=====================================|
//
// NOTE: Due to Mozilla bug 691003, we cannot reserve less than one word for an
// allocation on Linux or Mac. So on 32-bit *nix, the smallest bucket size is
// 4 bytes, and on 64-bit, the smallest bucket size is 8 bytes.
//
// A different mechanism is used for each category:
//
// Small : Each size class is segregated into its own set of runs. Each run
// maintains a bitmap of which regions are free/allocated.
//
// Large : Each allocation is backed by a dedicated run. Metadata are stored
// in the associated arena chunk header maps.
//
// Huge : Each allocation is backed by a dedicated contiguous set of chunks.
// Metadata are stored in a separate red-black tree.
//
// *****************************************************************************
Though, a more depth algorithm analysis is missing.