+static uns
+sorter_radix_bits(struct sort_context *ctx, struct sort_bucket *b)
+{
+ if (!b->hash_bits || !ctx->radix_split ||
+ (b->flags & SBF_CUSTOM_PRESORT) ||
+ (sorter_debug & SORT_DEBUG_NO_RADIX))
+ return 0;
+
+ u64 in = sbuck_size(b);
+ u64 mem = ctx->internal_estimate(ctx, b) * 0.8; // FIXME: Magical factor for hash non-uniformity
+ if (in <= mem)
+ return 0;
+
+ uns n = sorter_min_radix_bits;
+ while (n < sorter_max_radix_bits && n < b->hash_bits && (in >> n) > mem)
+ n++;
+ return n;
+}
+
+static void
+sorter_radix(struct sort_context *ctx, struct sort_bucket *b, uns bits)
+{
+ uns nbuck = 1 << bits;
+ SORT_XTRACE(2, "Running radix split on %s with hash %d bits of %d (expecting %s buckets)",
+ F_BSIZE(b), bits, b->hash_bits, stk_fsize(sbuck_size(b) / nbuck));
+ sorter_free_buf(ctx);
+ sorter_start_timer(ctx);
+
+ struct sort_bucket **outs = alloca(nbuck * sizeof(struct sort_bucket *));
+ for (uns i=nbuck; i--; )
+ {
+ outs[i] = sbuck_new(ctx);
+ outs[i]->hash_bits = b->hash_bits - bits;
+ clist_insert_after(&outs[i]->n, &b->n);
+ }
+
+ ctx->radix_split(ctx, b, outs, b->hash_bits - bits, bits);
+
+ u64 min = ~(u64)0, max = 0, sum = 0;
+ for (uns i=0; i<nbuck; i++)
+ {
+ u64 s = sbuck_size(outs[i]);
+ min = MIN(min, s);
+ max = MAX(max, s);
+ sum += s;
+ if (nbuck > 4)
+ sbuck_swap_out(outs[i]);
+ }
+
+ SORT_TRACE("Radix split (%d buckets, %s min, %s max, %s avg, %dMB/s)", nbuck,
+ stk_fsize(min), stk_fsize(max), stk_fsize(sum / nbuck), sorter_speed(ctx, sum));
+ sbuck_drop(b);
+}
+