Hi Johnny, On Thu, Feb 20, 2014 at 5:37 PM, Johnny Billquist <b...@update.uu.se> wrote: > Are you saying that you essentially avoid GC by creating a large fresh heap > every time you call something written in Haskell, and then delete the heap > when the Haskell function returns? And that the current piece of code > running in Haskell is short enough that GC never is done?
No, does not delete. Pool it. See following code compiled by Ajhc. Ajhc compile Haskell code into C code. https://gist.github.com/master-q/9109334 Please note auichIntr() function that is entry point C => Haskell. https://gist.github.com/master-q/9109334#file-hsmain-c-L2051 int auichIntr(HsPtr x272) { arena_t arena; gc_t gc; gc = NULL; arena = NULL; jhc_alloc_init(&gc,&arena); jhc_hs_init(gc,arena); int x273 = ((int)fFE$__CCall_auichIntr(gc,arena,(uintptr_t)x272)); jhc_alloc_fini(gc,arena); return x273; } The code post-calls jhc_alloc_fini() that pool Haskell heap (named megablock) into free_megablocks. https://github.com/ajhc/ajhc/blob/d93468e34f4514209048d4a92b1549e079ccd3fb/rts/rts/gc_jgc.c#L251 void jhc_alloc_fini(gc_t gc,arena_t arena) { -- snip -- SLIST_FOREACH(pg, &arena->monolithic_blocks, link) { SLIST_INSERT_HEAD(&free_monolithic_blocks, pg, link); } SLIST_FOREACH(mb, &arena->megablocks, next) { SLIST_INSERT_HEAD(&free_megablocks, mb, next); } if(arena->current_megablock) { SLIST_INSERT_HEAD(&free_megablocks, arena->current_megablock, next); } Also s_alloc(), Haskell heap allocator, try to get Haskell heap from the pool. If not found, it posix_memalign new megablock. https://github.com/ajhc/ajhc/blob/d93468e34f4514209048d4a92b1549e079ccd3fb/rts/rts/gc_jgc.c#L392 struct s_megablock * s_new_megablock(arena_t arena) { jhc_rts_lock(); struct s_megablock *mb = SLIST_FIRST(&free_megablocks); if (mb) { SLIST_REMOVE(&free_megablocks, mb, s_megablock, next); } else { mb = malloc(sizeof(*mb)); #ifdef _JHC_JGC_LIMITED_NUM_MEGABLOCK static int count = 0; if (count >= _JHC_JGC_LIMITED_NUM_MEGABLOCK) { abort(); } mb->base = aligned_megablock + (MEGABLOCK_SIZE) * count; count++; #else mb->base = jhc_aligned_alloc(MEGABLOCK_SIZE); #endif Regards, -- Kiwamu Okabe _______________________________________________ jhc mailing list jhc@haskell.org http://www.haskell.org/mailman/listinfo/jhc
