From 27a28cf6bc2196ee1690ac1fcc4d4c59d9b0d50f Mon Sep 17 00:00:00 2001 From: Simon Marlow Date: Wed, 16 Apr 2008 22:06:20 +0000 Subject: [PATCH] Keep track of an accurate count of live words in each step This means we can calculate slop easily, and also improve predictability of GC. --- includes/Storage.h | 1 + rts/Stats.c | 34 ++++++++++++++++++++-------------- rts/sm/GC.c | 24 ++++++++++++++---------- rts/sm/GC.h | 2 +- rts/sm/Storage.c | 6 +++--- 5 files changed, 39 insertions(+), 28 deletions(-) diff --git a/includes/Storage.h b/includes/Storage.h index 3fcdfeb..d7a8421 100644 --- a/includes/Storage.h +++ b/includes/Storage.h @@ -62,6 +62,7 @@ typedef struct step_ { bdescr * blocks; // blocks in this step unsigned int n_blocks; // number of blocks + unsigned int n_words; // number of words struct step_ * to; // destination step for live objects diff --git a/rts/Stats.c b/rts/Stats.c index 9a9acca..cd61116 100644 --- a/rts/Stats.c +++ b/rts/Stats.c @@ -675,40 +675,46 @@ void statDescribeGens(void) { nat g, s, mut, lge; - lnat live; + lnat live, slop; + lnat tot_live, tot_slop; bdescr *bd; step *step; debugBelch( -" Gen Steps Max Mut-list Step Blocks Live Large\n" -" Blocks Bytes Objects\n"); +"-----------------------------------------------------------------\n" +" Gen Max Mut-list Step Blocks Large Live Slop\n" +" Blocks Bytes Objects \n" +"-----------------------------------------------------------------\n"); - mut = 0; + tot_live = 0; + tot_slop = 0; for (g = 0; g < RtsFlags.GcFlags.generations; g++) { + mut = 0; for (bd = generations[g].mut_list; bd != NULL; bd = bd->link) { mut += (bd->free - bd->start) * sizeof(W_); } - debugBelch("%8d %8d %8d %9d", g, generations[g].n_steps, - generations[g].max_blocks, mut); + debugBelch("%5d %7d %9d", g, generations[g].max_blocks, mut); for (s = 0; s < generations[g].n_steps; s++) { step = &generations[g].steps[s]; - live = 0; for (bd = step->large_objects, lge = 0; bd; bd = bd->link) { lge++; } - // This live figure will be slightly less that the "live" figure - // given by +RTS -Sstderr, because we take don't count the - // slop at the end of each block. - live += countOccupied(step->blocks) + countOccupied(step->large_objects); + live = step->n_words + countOccupied(step->large_objects); if (s != 0) { - debugBelch("%36s",""); + debugBelch("%23s",""); } - debugBelch("%6d %8d %8ld %8d\n", s, step->n_blocks, - live, lge); + slop = (step->n_blocks + step->n_large_blocks) * BLOCK_SIZE_W - live; + debugBelch("%6d %8d %8d %8ld %8ld\n", s, step->n_blocks, lge, + live*sizeof(W_), slop*sizeof(W_)); + tot_live += live; + tot_slop += slop; } } + debugBelch("-----------------------------------------------------------------\n"); + debugBelch("%48s%8ld %8ld\n","",tot_live*sizeof(W_),tot_slop*sizeof(W_)); + debugBelch("-----------------------------------------------------------------\n"); debugBelch("\n"); } diff --git a/rts/sm/GC.c b/rts/sm/GC.c index a361175..722de0f 100644 --- a/rts/sm/GC.c +++ b/rts/sm/GC.c @@ -195,8 +195,6 @@ GarbageCollect ( rtsBool force_major_gc ) ACQUIRE_SM_LOCK; - debugTrace(DEBUG_gc, "starting GC"); - #if defined(RTS_USER_SIGNALS) if (RtsFlags.MiscFlags.install_signal_handlers) { // block signals @@ -248,11 +246,11 @@ GarbageCollect ( rtsBool force_major_gc ) } else { n_gc_threads = RtsFlags.ParFlags.gcThreads; } - trace(TRACE_gc|DEBUG_gc, "GC (gen %d): %dKB to collect, using %d thread(s)", - N, n * (BLOCK_SIZE / 1024), n_gc_threads); #else n_gc_threads = 1; #endif + trace(TRACE_gc|DEBUG_gc, "GC (gen %d): %dKB to collect, using %d thread(s)", + N, n * (BLOCK_SIZE / 1024), n_gc_threads); #ifdef RTS_GTK_FRONTPANEL if (RtsFlags.GcFlags.frontpanel) { @@ -432,6 +430,7 @@ GarbageCollect ( rtsBool force_major_gc ) prev = ws->part_list; for (bd = ws->part_list; bd != NULL; bd = bd->link) { bd->flags &= ~BF_EVACUATED; // now from-space + ws->step->n_words += bd->free - bd->start; prev = bd; } if (prev != NULL) { @@ -439,6 +438,7 @@ GarbageCollect ( rtsBool force_major_gc ) } for (bd = ws->scavd_list; bd != NULL; bd = bd->link) { bd->flags &= ~BF_EVACUATED; // now from-space + ws->step->n_words += bd->free - bd->start; prev = bd; } prev->link = ws->step->blocks; @@ -450,6 +450,7 @@ GarbageCollect ( rtsBool force_major_gc ) ws->step->n_blocks += ws->n_part_blocks; ws->step->n_blocks += ws->n_scavd_blocks; ASSERT(countBlocks(ws->step->blocks) == ws->step->n_blocks); + ASSERT(countOccupied(ws->step->blocks) == ws->step->n_words); } } } @@ -523,6 +524,7 @@ GarbageCollect ( rtsBool force_major_gc ) // onto the front of the now-compacted existing blocks. for (bd = stp->blocks; bd != NULL; bd = bd->link) { bd->flags &= ~BF_EVACUATED; // now from-space + stp->n_words += bd->free - bd->start; } // tack the new blocks on the end of the existing blocks if (stp->old_blocks != NULL) { @@ -542,6 +544,7 @@ GarbageCollect ( rtsBool force_major_gc ) // add the new blocks to the block tally stp->n_blocks += stp->n_old_blocks; ASSERT(countBlocks(stp->blocks) == stp->n_blocks); + ASSERT(countOccupied(stp->blocks) == stp->n_words); } else // not copacted { @@ -591,10 +594,8 @@ GarbageCollect ( rtsBool force_major_gc ) // update the max size of older generations after a major GC resize_generations(); - // Guess the amount of live data for stats. - live = calcLiveBlocks() * BLOCK_SIZE_W; - debugTrace(DEBUG_gc, "Slop: %ldKB", - (live - calcLiveWords()) / (1024/sizeof(W_))); + // Calculate the amount of live data for stats. + live = calcLiveWords(); // Free the small objects allocated via allocate(), since this will // all have been copied into G0S1 now. @@ -604,6 +605,7 @@ GarbageCollect ( rtsBool force_major_gc ) g0s0->blocks = NULL; } g0s0->n_blocks = 0; + g0s0->n_words = 0; } alloc_blocks = 0; alloc_blocks_lim = RtsFlags.GcFlags.minAllocAreaSize; @@ -941,7 +943,7 @@ initialise_N (rtsBool force_major_gc) for (g = RtsFlags.GcFlags.generations - 1; g >= 0; g--) { blocks = 0; for (s = 0; s < generations[g].n_steps; s++) { - blocks += generations[g].steps[s].n_blocks; + blocks += generations[g].steps[s].n_words / BLOCK_SIZE_W; blocks += generations[g].steps[s].n_large_blocks; } if (blocks >= generations[g].max_blocks) { @@ -1254,6 +1256,7 @@ init_collected_gen (nat g, nat n_threads) stp->n_old_blocks = stp->n_blocks; stp->blocks = NULL; stp->n_blocks = 0; + stp->n_words = 0; // we don't have any to-be-scavenged blocks yet stp->todos = NULL; @@ -1379,6 +1382,7 @@ init_uncollected_gen (nat g, nat threads) ws->todo_lim = ws->todo_bd->start + BLOCK_SIZE_W; stp->blocks = stp->blocks->link; stp->n_blocks -= 1; + stp->n_words -= ws->todo_bd->free - ws->todo_bd->start; ws->todo_bd->link = NULL; // this block is also the scan block; we must scan @@ -1549,7 +1553,7 @@ resize_generations (void) nat gens = RtsFlags.GcFlags.generations; // live in the oldest generations - live = oldest_gen->steps[0].n_blocks + + live = (oldest_gen->steps[0].n_words + BLOCK_SIZE_W - 1) / BLOCK_SIZE_W+ oldest_gen->steps[0].n_large_blocks; // default max size for all generations except zero diff --git a/rts/sm/GC.h b/rts/sm/GC.h index bc14840..5a9cb98 100644 --- a/rts/sm/GC.h +++ b/rts/sm/GC.h @@ -92,7 +92,7 @@ typedef struct step_workspace_ { // Objects that have already been, scavenged. bdescr * scavd_list; - lnat n_scavd_blocks; // count of blocks in this list + nat n_scavd_blocks; // count of blocks in this list // Partially-full, scavenged, blocks bdescr * part_list; diff --git a/rts/sm/Storage.c b/rts/sm/Storage.c index 6b16cc4..6f4a415 100644 --- a/rts/sm/Storage.c +++ b/rts/sm/Storage.c @@ -87,6 +87,7 @@ initStep (step *stp, int g, int s) stp->abs_no = RtsFlags.GcFlags.steps * g + s; stp->blocks = NULL; stp->n_blocks = 0; + stp->n_words = 0; stp->old_blocks = NULL; stp->n_old_blocks = 0; stp->gen = &generations[g]; @@ -999,7 +1000,7 @@ calcLiveWords(void) step *stp; if (RtsFlags.GcFlags.generations == 1) { - return countOccupied(g0s0->blocks) + countOccupied(g0s0->large_objects); + return g0s0->n_words + countOccupied(g0s0->large_objects); } live = 0; @@ -1007,8 +1008,7 @@ calcLiveWords(void) for (s = 0; s < generations[g].n_steps; s++) { if (g == 0 && s == 0) continue; stp = &generations[g].steps[s]; - live += countOccupied(stp->blocks) + - countOccupied(stp->large_objects); + live += stp->n_words + countOccupied(stp->large_objects); } } return live; -- 1.7.10.4