Author: cem Date: Sat Apr 13 04:42:17 2019 New Revision: 346175 URL: https://svnweb.freebsd.org/changeset/base/346175
Log: sort(1): Memoize MD5 computation to reduce repeated computation Experimentally, reduces sort -R time of a 148160 line corpus from about 3.15s to about 0.93s on this particular system. There's probably room for improvement using some digest other than md5, but I don't want to look at sort(1) anymore. Some discussion of other possible improvements in the Test Plan section of the Differential. PR: 230792 Reviewed by: jhb (earlier version) Differential Revision: https://reviews.freebsd.org/D19885 Modified: head/usr.bin/sort/coll.c head/usr.bin/sort/coll.h head/usr.bin/sort/sort.c Modified: head/usr.bin/sort/coll.c ============================================================================== --- head/usr.bin/sort/coll.c Sat Apr 13 04:03:18 2019 (r346174) +++ head/usr.bin/sort/coll.c Sat Apr 13 04:42:17 2019 (r346175) @@ -981,6 +981,15 @@ hnumcoll(struct key_value *kv1, struct key_value *kv2, return (numcoll_impl(kv1, kv2, offset, true)); } +/* Use hint space to memoize md5 computations, at least. */ +static void +randomcoll_init_hint(struct key_value *kv, void *hash) +{ + + memcpy(kv->hint->v.Rh.cached, hash, sizeof(kv->hint->v.Rh.cached)); + kv->hint->status = HS_INITIALIZED; +} + /* * Implements random sort (-R). */ @@ -991,6 +1000,7 @@ randomcoll(struct key_value *kv1, struct key_value *kv struct bwstring *s1, *s2; MD5_CTX ctx1, ctx2; unsigned char hash1[MD5_DIGEST_LENGTH], hash2[MD5_DIGEST_LENGTH]; + int cmp; s1 = kv1->k; s2 = kv2->k; @@ -1003,6 +1013,14 @@ randomcoll(struct key_value *kv1, struct key_value *kv if (s1 == s2) return (0); + if (kv1->hint->status == HS_INITIALIZED && + kv2->hint->status == HS_INITIALIZED) { + cmp = memcmp(kv1->hint->v.Rh.cached, + kv2->hint->v.Rh.cached, sizeof(kv1->hint->v.Rh.cached)); + if (cmp != 0) + return (cmp); + } + memcpy(&ctx1, &md5_ctx, sizeof(MD5_CTX)); memcpy(&ctx2, &md5_ctx, sizeof(MD5_CTX)); @@ -1011,6 +1029,11 @@ randomcoll(struct key_value *kv1, struct key_value *kv MD5Final(hash1, &ctx1); MD5Final(hash2, &ctx2); + + if (kv1->hint->status == HS_UNINITIALIZED) + randomcoll_init_hint(kv1, hash1); + if (kv2->hint->status == HS_UNINITIALIZED) + randomcoll_init_hint(kv2, hash2); return (memcmp(hash1, hash2, sizeof(hash1))); } Modified: head/usr.bin/sort/coll.h ============================================================================== --- head/usr.bin/sort/coll.h Sat Apr 13 04:03:18 2019 (r346174) +++ head/usr.bin/sort/coll.h Sat Apr 13 04:42:17 2019 (r346175) @@ -65,6 +65,17 @@ struct M_hint }; /* + * Sort hint data for -R + * + * This stores the first 12 bytes of the digest rather than the full output to + * avoid increasing the size of the 'key_hint' object via the 'v' union. + */ +struct R_hint +{ + unsigned char cached[12]; +}; + +/* * Status of a sort hint object */ typedef enum @@ -83,6 +94,7 @@ struct key_hint struct n_hint nh; struct g_hint gh; struct M_hint Mh; + struct R_hint Rh; } v; }; Modified: head/usr.bin/sort/sort.c ============================================================================== --- head/usr.bin/sort/sort.c Sat Apr 13 04:03:18 2019 (r346174) +++ head/usr.bin/sort/sort.c Sat Apr 13 04:42:17 2019 (r346175) @@ -583,6 +583,7 @@ set_sort_modifier(struct sort_mods *sm, int c) break; case 'R': sm->Rflag = true; + need_hint = true; need_random = true; break; case 'M': _______________________________________________ svn-src-head@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
