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444 lines
13 KiB
444 lines
13 KiB
2 months ago
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/*
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* UCW Library -- Universal Sorter: Governing Routines
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*
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* (c) 2007 Martin Mares <mj@ucw.cz>
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*
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* This software may be freely distributed and used according to the terms
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* of the GNU Lesser General Public License.
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*/
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#include <ucw/lib.h>
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#include <ucw/fastbuf.h>
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#include <ucw/mempool.h>
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#include <ucw/stkstring.h>
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#include <ucw/time.h>
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#include <ucw/sorter/common.h>
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#include <string.h>
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#include <sys/time.h>
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#include <time.h>
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#define F_BSIZE(b) stk_fsize(sbuck_size(b))
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static void
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sorter_start_timer(struct sort_context *ctx)
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{
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init_timer(&ctx->start_time);
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}
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static void
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sorter_stop_timer(struct sort_context *ctx, uint *account_to)
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{
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ctx->last_pass_time = get_timer(&ctx->start_time);
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*account_to += ctx->last_pass_time;
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}
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static uint
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sorter_speed(struct sort_context *ctx, u64 size)
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{
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if (!size)
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return 0;
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if (!ctx->last_pass_time)
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return 0;
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return (uint)((double)size / (1<<20) * 1000 / ctx->last_pass_time);
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}
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static int
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sorter_presort(struct sort_context *ctx, struct sort_bucket *in, struct sort_bucket *out, struct sort_bucket *out_only)
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{
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sorter_alloc_buf(ctx);
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if (in->flags & SBF_CUSTOM_PRESORT)
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{
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/*
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* The trick with automatic joining, which we use for the normal presorter,
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* is not necessary with the custom presorter, because the custom presorter
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* is never called in the middle of the sorted data.
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*/
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struct fastbuf *f = sbuck_write(out);
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out->runs++;
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return ctx->custom_presort(f, ctx->big_buf, ctx->big_buf_size);
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}
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return ctx->internal_sort(ctx, in, out, out_only);
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}
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static struct sort_bucket *
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sbuck_join_to(struct sort_bucket *b, ucw_off_t *sizep)
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{
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*sizep = 0; // Not needed, just to silence false warnings in some compilers about uninitialized sizep (it's OK for NULL result)
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if (sorter_debug & SORT_DEBUG_NO_JOIN)
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return NULL;
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struct sort_bucket *out = (struct sort_bucket *) b->n.prev; // Such bucket is guaranteed to exist
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if (!(out->flags & SBF_FINAL))
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return NULL;
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ASSERT(out->runs == 1);
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*sizep = sbuck_size(out);
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return out;
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}
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static ucw_off_t
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sbuck_ins_or_join(struct sort_bucket *b, cnode *list_pos, struct sort_bucket *join, ucw_off_t join_size)
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{
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if (join && join->runs >= 2)
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{
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if (b)
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sbuck_drop(b);
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ASSERT(join->runs == 2);
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join->runs--;
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return sbuck_size(join) - join_size;
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}
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else if (b)
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{
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clist_insert_after(&b->n, list_pos);
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return sbuck_size(b);
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}
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else
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return 0;
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}
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static void
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sorter_join(struct sort_bucket *b)
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{
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struct sort_bucket *join = (struct sort_bucket *) b->n.prev;
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ASSERT(join->flags & SBF_FINAL);
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ASSERT(b->runs == 1);
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if (!sbuck_has_file(join))
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{
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// The final bucket doesn't have any file associated yet, so replace
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// it with the new bucket.
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SORT_XTRACE(3, "Replaced final bucket");
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b->flags |= SBF_FINAL;
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sbuck_drop(join);
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}
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else
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{
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SORT_TRACE("Copying to output file: %s", F_BSIZE(b));
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struct fastbuf *src = sbuck_read(b);
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struct fastbuf *dest = sbuck_write(join);
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bbcopy(src, dest, ~0U);
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sbuck_drop(b);
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}
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}
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static void
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sorter_twoway(struct sort_context *ctx, struct sort_bucket *b)
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{
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struct sort_bucket *ins[3] = { NULL }, *outs[3] = { NULL };
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cnode *list_pos = b->n.prev;
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ucw_off_t join_size;
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struct sort_bucket *join = sbuck_join_to(b, &join_size);
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if (!(sorter_debug & SORT_DEBUG_NO_PRESORT) || (b->flags & SBF_CUSTOM_PRESORT))
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{
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SORT_XTRACE(3, "%s", ((b->flags & SBF_CUSTOM_PRESORT) ? "Custom presorting" : "Presorting"));
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sorter_start_timer(ctx);
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ins[0] = sbuck_new(ctx);
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if (!sorter_presort(ctx, b, ins[0], join ? : ins[0]))
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{
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sorter_stop_timer(ctx, &ctx->total_pre_time);
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ucw_off_t size = sbuck_ins_or_join(ins[0], list_pos, join, join_size);
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SORT_XTRACE(((b->flags & SBF_SOURCE) ? 1 : 3), "Sorted in memory (%s, %dMB/s)", stk_fsize(size), sorter_speed(ctx, size));
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sbuck_drop(b);
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return;
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}
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ins[1] = sbuck_new(ctx);
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int i = 1;
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while (sorter_presort(ctx, b, ins[i], ins[i]))
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i = 1-i;
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sbuck_drop(b);
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sorter_stop_timer(ctx, &ctx->total_pre_time);
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SORT_TRACE("Presorting pass (%d+%d runs, %s+%s, %dMB/s)",
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ins[0]->runs, ins[1]->runs,
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F_BSIZE(ins[0]), F_BSIZE(ins[1]),
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sorter_speed(ctx, sbuck_size(ins[0]) + sbuck_size(ins[1])));
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}
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else
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{
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SORT_XTRACE(2, "Presorting disabled");
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ins[0] = b;
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}
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SORT_XTRACE(3, "Main sorting");
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uint pass = 0;
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do {
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++pass;
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sorter_start_timer(ctx);
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if (ins[0]->runs <= 1 && ins[1]->runs <= 1 && join)
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{
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// This is guaranteed to produce a single run, so join if possible
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outs[0] = join;
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outs[1] = NULL;
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ctx->twoway_merge(ctx, ins, outs);
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ucw_off_t size = sbuck_ins_or_join(NULL, NULL, join, join_size);
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sorter_stop_timer(ctx, &ctx->total_ext_time);
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SORT_TRACE("Mergesort pass %d (final run, %s, %dMB/s)", pass, stk_fsize(size), sorter_speed(ctx, size));
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sbuck_drop(ins[0]);
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sbuck_drop(ins[1]);
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return;
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}
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outs[0] = sbuck_new(ctx);
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outs[1] = sbuck_new(ctx);
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outs[2] = NULL;
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ctx->twoway_merge(ctx, ins, outs);
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sorter_stop_timer(ctx, &ctx->total_ext_time);
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SORT_TRACE("Mergesort pass %d (%d+%d runs, %s+%s, %dMB/s)", pass,
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outs[0]->runs, outs[1]->runs,
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F_BSIZE(outs[0]), F_BSIZE(outs[1]),
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sorter_speed(ctx, sbuck_size(outs[0]) + sbuck_size(outs[1])));
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sbuck_drop(ins[0]);
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sbuck_drop(ins[1]);
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memcpy(ins, outs, 3*sizeof(struct sort_bucket *));
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} while (sbuck_have(ins[1]));
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sbuck_drop(ins[1]);
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clist_insert_after(&ins[0]->n, list_pos);
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}
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static void
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sorter_multiway(struct sort_context *ctx, struct sort_bucket *b)
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{
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clist parts;
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cnode *list_pos = b->n.prev;
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ucw_off_t join_size;
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struct sort_bucket *join = sbuck_join_to(b, &join_size);
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uint trace_level = (b->flags & SBF_SOURCE) ? 1 : 3;
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clist_init(&parts);
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ASSERT(!(sorter_debug & SORT_DEBUG_NO_PRESORT));
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SORT_XTRACE(3, "%s", ((b->flags & SBF_CUSTOM_PRESORT) ? "Custom presorting" : "Presorting"));
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uint cont;
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uint part_cnt = 0;
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u64 total_size = 0;
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sorter_start_timer(ctx);
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do
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{
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struct sort_bucket *p = sbuck_new(ctx);
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cont = sorter_presort(ctx, b, p, (!part_cnt && join) ? join : p);
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if (sbuck_have(p))
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{
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part_cnt++;
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clist_add_tail(&parts, &p->n);
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total_size += sbuck_size(p);
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sbuck_swap_out(p);
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}
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else
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sbuck_drop(p);
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}
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while (cont);
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sorter_stop_timer(ctx, &ctx->total_pre_time);
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sorter_free_buf(ctx);
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sbuck_drop(b);
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if (part_cnt <= 1)
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{
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ucw_off_t size = sbuck_ins_or_join(clist_head(&parts), list_pos, (part_cnt ? NULL : join), join_size);
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SORT_XTRACE(trace_level, "Sorted in memory (%s, %dMB/s)", stk_fsize(size), sorter_speed(ctx, size));
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return;
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}
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SORT_TRACE("Multi-way presorting pass (%d parts, %s, %dMB/s)", part_cnt, stk_fsize(total_size), sorter_speed(ctx, total_size));
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uint max_ways = 1 << sorter_max_multiway_bits;
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struct sort_bucket *ways[max_ways+1];
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SORT_XTRACE(3, "Starting up to %d-way merge", max_ways);
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for (;;)
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{
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uint n = 0;
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struct sort_bucket *p;
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while (n < max_ways && (p = clist_head(&parts)))
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{
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clist_remove(&p->n);
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ways[n++] = p;
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}
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ways[n] = NULL;
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ASSERT(n > 1);
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struct sort_bucket *out;
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if (clist_empty(&parts) && join)
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out = join;
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else
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out = sbuck_new(ctx);
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sorter_start_timer(ctx);
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ctx->multiway_merge(ctx, ways, out);
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sorter_stop_timer(ctx, &ctx->total_ext_time);
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for (uint i=0; i<n; i++)
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sbuck_drop(ways[i]);
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if (clist_empty(&parts))
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{
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ucw_off_t size = sbuck_ins_or_join((join ? NULL : out), list_pos, join, join_size);
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SORT_TRACE("Multi-way merge completed (%d ways, %s, %dMB/s)", n, stk_fsize(size), sorter_speed(ctx, size));
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return;
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}
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else
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{
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sbuck_swap_out(out);
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clist_add_tail(&parts, &out->n);
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SORT_TRACE("Multi-way merge pass (%d ways, %s, %dMB/s)", n, F_BSIZE(out), sorter_speed(ctx, sbuck_size(out)));
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}
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}
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}
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static void
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sorter_radix(struct sort_context *ctx, struct sort_bucket *b, uint bits)
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{
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// Add more bits if requested and allowed.
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bits = MIN(bits + sorter_add_radix_bits, sorter_max_radix_bits);
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uint nbuck = 1 << bits;
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SORT_XTRACE(3, "Running radix split on %s with hash %d bits of %d (expecting %s buckets)",
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F_BSIZE(b), bits, b->hash_bits, stk_fsize(sbuck_size(b) / nbuck));
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sorter_free_buf(ctx);
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sorter_start_timer(ctx);
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struct sort_bucket **outs = alloca(nbuck * sizeof(struct sort_bucket *));
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for (uint i=nbuck; i--; )
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{
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outs[i] = sbuck_new(ctx);
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outs[i]->hash_bits = b->hash_bits - bits;
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clist_insert_after(&outs[i]->n, &b->n);
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}
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ctx->radix_split(ctx, b, outs, b->hash_bits - bits, bits);
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u64 min = ~(u64)0, max = 0, sum = 0;
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for (uint i=0; i<nbuck; i++)
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{
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u64 s = sbuck_size(outs[i]);
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min = MIN(min, s);
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max = MAX(max, s);
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sum += s;
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if (nbuck > 4)
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sbuck_swap_out(outs[i]);
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}
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sorter_stop_timer(ctx, &ctx->total_ext_time);
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SORT_TRACE("Radix split (%d buckets, %s min, %s max, %s avg, %dMB/s)", nbuck,
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stk_fsize(min), stk_fsize(max), stk_fsize(sum / nbuck), sorter_speed(ctx, sum));
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sbuck_drop(b);
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}
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static void
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sorter_decide(struct sort_context *ctx, struct sort_bucket *b)
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{
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// Drop empty buckets
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if (!sbuck_have(b))
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{
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SORT_XTRACE(4, "Dropping empty bucket");
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sbuck_drop(b);
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return;
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}
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// How many bits of bucket size we have to reduce before it fits in the RAM?
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// (this is insanely large if the input size is unknown, but it serves our purpose)
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u64 insize = sbuck_size(b);
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u64 mem = ctx->internal_estimate(ctx, b) * 0.8; // Magical factor accounting for various non-uniformities
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uint bits = 0;
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while ((insize >> bits) > mem)
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bits++;
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// Calculate the possibilities of radix splits
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uint radix_bits;
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if (!ctx->radix_split ||
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(b->flags & SBF_CUSTOM_PRESORT) ||
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(sorter_debug & SORT_DEBUG_NO_RADIX))
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radix_bits = 0;
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else
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{
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radix_bits = MIN(bits, b->hash_bits);
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radix_bits = MIN(radix_bits, sorter_max_radix_bits);
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if (radix_bits < sorter_min_radix_bits)
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radix_bits = 0;
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}
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// The same for multi-way merges
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uint multiway_bits;
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if (!ctx->multiway_merge ||
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(sorter_debug & SORT_DEBUG_NO_MULTIWAY) ||
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(sorter_debug & SORT_DEBUG_NO_PRESORT))
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multiway_bits = 0;
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else
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{
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multiway_bits = MIN(bits, sorter_max_multiway_bits);
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if (multiway_bits < sorter_min_multiway_bits)
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multiway_bits = 0;
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}
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SORT_XTRACE(3, "Decisions: size=%s max=%s runs=%d bits=%d hash=%d -> radix=%d multi=%d",
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stk_fsize(insize), stk_fsize(mem), b->runs, bits, b->hash_bits,
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radix_bits, multiway_bits);
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// If the input already consists of a single run, just join it
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if (b->runs)
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return sorter_join(b);
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// If everything fits in memory, the 2-way strategy will sort it in memory
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if (!bits)
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return sorter_twoway(ctx, b);
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// If we can reduce everything in one pass, do so and prefer radix splits
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if (radix_bits == bits)
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return sorter_radix(ctx, b, radix_bits);
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if (multiway_bits == bits)
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return sorter_multiway(ctx, b);
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// Otherwise, reduce as much as possible and again prefer radix splits
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if (radix_bits)
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return sorter_radix(ctx, b, radix_bits);
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if (multiway_bits)
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return sorter_multiway(ctx, b);
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// Fall back to 2-way strategy if nothing else applies
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return sorter_twoway(ctx, b);
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}
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|
||
|
void
|
||
|
sorter_run(struct sort_context *ctx)
|
||
|
{
|
||
|
ctx->pool = mp_new(4096);
|
||
|
clist_init(&ctx->bucket_list);
|
||
|
sorter_prepare_buf(ctx);
|
||
|
asort_start_threads(0);
|
||
|
|
||
|
// Create bucket containing the source
|
||
|
struct sort_bucket *bin = sbuck_new(ctx);
|
||
|
bin->flags = SBF_SOURCE | SBF_OPEN_READ;
|
||
|
if (ctx->custom_presort)
|
||
|
bin->flags |= SBF_CUSTOM_PRESORT;
|
||
|
else
|
||
|
bin->fb = ctx->in_fb;
|
||
|
bin->ident = "in";
|
||
|
bin->size = ctx->in_size;
|
||
|
bin->hash_bits = ctx->hash_bits;
|
||
|
clist_add_tail(&ctx->bucket_list, &bin->n);
|
||
|
SORT_XTRACE(2, "Input size: %s, %d hash bits", F_BSIZE(bin), bin->hash_bits);
|
||
|
ctx->fb_params = (bin->size < sorter_small_input) ? &sorter_small_fb_params : &sorter_fb_params;
|
||
|
|
||
|
// Create bucket for the output
|
||
|
struct sort_bucket *bout = sbuck_new(ctx);
|
||
|
bout->flags = SBF_FINAL;
|
||
|
if (bout->fb = ctx->out_fb)
|
||
|
bout->flags |= SBF_OPEN_WRITE;
|
||
|
bout->ident = "out";
|
||
|
bout->runs = 1;
|
||
|
clist_add_head(&ctx->bucket_list, &bout->n);
|
||
|
|
||
|
// Repeatedly sort buckets
|
||
|
struct sort_bucket *b;
|
||
|
while (bout = clist_head(&ctx->bucket_list), b = clist_next(&ctx->bucket_list, &bout->n))
|
||
|
sorter_decide(ctx, b);
|
||
|
|
||
|
asort_stop_threads();
|
||
|
sorter_free_buf(ctx);
|
||
|
sbuck_write(bout); // Force empty bucket to a file
|
||
|
SORT_XTRACE(2, "Final size: %s", F_BSIZE(bout));
|
||
|
SORT_XTRACE(2, "Final timings: %.3fs external sorting, %.3fs presorting, %.3fs internal sorting",
|
||
|
ctx->total_ext_time/1000., ctx->total_pre_time/1000., ctx->total_int_time/1000.);
|
||
|
ctx->out_fb = sbuck_read(bout);
|
||
|
mp_delete(ctx->pool);
|
||
|
}
|