On Sun, 27 Mar 2011 12:09:03 +0900, dsimcha <[email protected]> wrote:
On 3/18/2011 2:56 AM, Don wrote:
3. TempAlloc: A memory allocator based on a thread-local segmented
stack,
useful for allocating large temporary buffers in things like numerics
code.
Also comes with a hash table, hash set and AVL tree optimized for this
allocation scheme. The advantages over plain old stack allocation are
that
it's independent of function calls (meaning you can return pointers to
TempAlloc-allocated memory from a function, etc.) and it's segmented,
meaning
you can allocate huge buffers w/o risking stack overflow. Its main
weakness
is that this stack is not scanned by the GC, meaning that you can't
store the
only reference to a GC-allocated piece of memory here. However, in
practice
large arrays of primitives are an extremely common case in
performance-critical code. I find this module immensely useful in
dstats and
Lars Kyllingstad uses it in SciD. Getting it into Phobos would make it
easy
for other scientific/numerics code to use it. Completion state:
Working and
used. Needs a litte cleanup and documentation. (Phobos candidate)
This is #1. Far and away. Belongs in druntime.
I would use it instantly in BigInt.
This is not up for "official" review yet because std.net.isemail and
std.parallelism (and possibly more stuff depending on how we manage the
review queue) are ahead of it. If you want a sneak preview:
Code:
https://github.com/dsimcha/TempAlloc
Docs:
http://cis.jhu.edu/~dsimcha/d/phobos/core_tempalloc.html
I put in a few small, tangentially related memory allocation functions
that I've wanted in druntime/Phobos for awhile in this proposal, too.
alignedMalloc() and alignedFree() are used by TempAlloc but can be made
private if people don't like them. newVoid() is not used by TempAlloc
and might fit better in std.array, but I think it belongs somewhere in
Phobos or druntime.
Now, I am thinking of light-weight process for concurrency.
Your TempAlloc(segmented stack) seems to be a good parts for implementing
such feature :)
Masahiro
