TLSFMem O(1) Memory Allocator

[platon42]

For my own (very old) FolderSync program, I was able to gain a 70 times speed-up by writing my own custom memory allocation system. The reason is that (a) AmigaOS 3.x has a very old & slow memory allocation system, and (b) FolderSync made very many (small) memory allocations.

Isn't that what memory pools, introduced with OS 2.0 is for? Small allocations, pooled into puddles? Unfortunately, there are still programs, that don't use them, way past the OS 2.0 release date...

[platon42]

I have found a serious problem with your patch:
Every WOS and PUP progs i have tried so far, refuses to work when TLSFMem is installed.

So.. Is there anyone with a PPC board who confirms this?

Seems to be true. I guess PUP and WarpOS have their own allocation routines for PPC, which are of course not patched with TLSFMem, and as TLSFMem grabs most available memory, they will at least suffer from "out of memory" problems.

[ChrisH]

Isn't that what memory pools, introduced with OS 2.0 is for? Small allocations, pooled into puddles? Unfortunately, there are still programs, that don't use them, way past the OS 2.0 release date...

Bleugh, memory pools are disgusting!  You have to manually manage them, rather than having it automatically allocate/choose automatically sized 'pools' for you.  i.e. mine simply replaced the existing AllocMem() routines, like yours does (but only for my program) - no hassle.

If the OS4 allocator has internal fragmentation and if it's really up to 12,5%, it sucks.

Well, that is a lot better than all previous memory allocators, the fragmentation can never exceed 12.5%, and it is apparently used by Linux & other modern OSes.

P.S.  Yes, I will look at the TLSF papers when I have time (already downloaded).  Pity you didn't link to the paper, as it took a while to find (most places wanted payment!).

[dammy]

No. I don't think that ~2000 lines of 68k-asm would be helpful for AROS either. There is that paper and at least two open source implementations of TLSF in C on the internet.

No help to AROSm68K Devs?


Dammy

[AmigaMance]

@platon42
 A pity because according to AllocatorBenchmark, your patch is superior from the others. :-(

[Rabbi]

Two questions I have that anyone can help answer me with:

Q1: When I try to make a back-up of my HD by using MakeCD to copy my hundreds of files, it seems to hang, not doing anything.  Is it this a memory problem that TLFS can resolve or is it some other problem?

Q2:I've got the Elbox Fast ATA 1200 MK-III 32-bit High Speed ATA-2 EIDE Controller for the A1200 & the Elbox 4000 MK III for the A4000.  Would it be safe to use it with these hardware devices and partition HDs without any problems or will I have to find out for myself?

 :-?

[JosephC]

A1: Probably Yes.  I had the same problem on my system and both PoolMem or TLSFmem solve it for me.

A2: Should be 100% safe.

[ChrisH]

I finally got around to trying TLSFMem on my OS3.9.2 WinUAE system, and sadly it crashes my system *immediately*, even when I disable User-Startup (which has a lot of patches).  Which is a pity, because I was hoping it would have been a superior alternative to my own (program specific) fast memory allocator...

[JosephC]

@ChrisH

Check your Startup-Sequence for anything that might be patching your memory allocation routines.  MCP? PoolMem?  MemSniff?  MungWall? Ixemul?