diff options
Diffstat (limited to 'research/experiments/024-finding-items/prefetch.patch')
| -rw-r--r-- | research/experiments/024-finding-items/prefetch.patch | 21 |
1 files changed, 21 insertions, 0 deletions
diff --git a/research/experiments/024-finding-items/prefetch.patch b/research/experiments/024-finding-items/prefetch.patch new file mode 100644 index 0000000..e642352 --- /dev/null +++ b/research/experiments/024-finding-items/prefetch.patch @@ -0,0 +1,21 @@ +--- a/core/module-list.c ++++ b/core/module-list.c +@@ -1122,12 +1122,17 @@ + unsigned taken = upper(g->keys + 1, FANOUT - 1, key.num); + start += g->before[taken]; + node = child(node, taken); ++ if (!node->leaf) ++ for (unsigned i = 0; i < FANOUT; i += 8) __builtin_prefetch(guide(node)->keys + i); + } + const double *keys = numbers(l, node, field); +- if (list->count > PREFETCHED) /* leaves past the caches: the leaf's keys fetched at once, not probe by probe */ ++ if (true) /* the leaf's keys fetched at once, not probe by probe */ + for (unsigned i = 0; i < node->count; i += 8) __builtin_prefetch(keys + i); + unsigned low = lower(keys, node->count, key.num); + *found = low < node->count && keys[low] == key.num; ++ if (*found) /* the item is read next, a field at a time: its cells, a line each, fetched together */ ++ for (unsigned f = 0; f < l->fields; ++f) ++ __builtin_prefetch(l->text_fields[f] ? (const void *)&texts(l, node, f)[low] : (const void *)&numbers(l, node, f)[low]); + return start + low; + } + while (!node->leaf) { |