On Wed, May 29, 2013 at 02:20:07AM -0400, Jeff King wrote:
> In the best case, we compute no patch-ids at all. And even for the
> average case, I'd expect our lazy calculation to only have to compute a
> handful of ids.
Here is a not-well-tested version of the idea. I tried to contain the
changes to patch-ids.c, though we may also be able to simplify the
--cherry code, too.
Here are my timings compared to stock git and to yours
(all are best-of-five, "git log --cherry $revs"):
revs=origin/master...origin/jk/submodule-subdirectory-ok
stock | you | me
-------------------------------
real 0m0.501s | 0m0.078s | 0m0.098s
user 0m0.480s | 0m0.056s | 0m0.084s
sys 0m0.016s | 0m0.020s | 0m0.012s
revs=origin/next...origin/pu
stock | you | me
-------------------------------
real 0m0.857s | 0m0.847s | 0m0.519s
user 0m0.828s | 0m0.812s | 0m0.488s
sys 0m0.024s | 0m0.028s | 0m0.024s
So it performs slightly less well on the small case, and a bit better on
the large case. I think part of the problem is that when we do have a
"loose" hit, we end up re-doing the tree diff to find the strict, which
involves re-inflating the trees. It's unavoidable for the lazy entries
unless we want to cache the whole diff_queued_diff, but for the non-lazy
entries we should be able to do the strict patch-id incrementally. We
just need to improve the function interfaces.
---
diff.c | 15 ++++-
diff.h | 2 +-
patch-ids.c | 117 +++++++++++++++++++----------------
patch-ids.h | 11 ++--
4 files changed, 82 insertions(+), 63 deletions(-)
diff --git a/diff.c b/diff.c
index f0b3e7c..3b55788 100644
--- a/diff.c
+++ b/diff.c
@@ -4233,7 +4233,8 @@ static void patch_id_consume(void *priv, char *line,
unsigned long len)
}
/* returns 0 upon success, and writes result into sha1 */
-static int diff_get_patch_id(struct diff_options *options, unsigned char *sha1)
+static int diff_get_patch_id(struct diff_options *options, unsigned char *sha1,
+ int loose)
{
struct diff_queue_struct *q = &diff_queued_diff;
int i;
@@ -4266,6 +4267,12 @@ static int diff_get_patch_id(struct diff_options
*options, unsigned char *sha1)
if (DIFF_PAIR_UNMERGED(p))
continue;
+ if (loose) {
+ git_SHA1_Update(&ctx, p->one->path,
strlen(p->one->path));
+ git_SHA1_Update(&ctx, p->two->path,
strlen(p->two->path));
+ continue;
+ }
+
diff_fill_sha1_info(p->one);
diff_fill_sha1_info(p->two);
if (fill_mmfile(&mf1, p->one) < 0 ||
@@ -4323,11 +4330,13 @@ int diff_flush_patch_id(struct diff_options *options,
unsigned char *sha1)
return 0;
}
-int diff_flush_patch_id(struct diff_options *options, unsigned char *sha1)
+int diff_flush_patch_id(struct diff_options *options,
+ unsigned char *sha1,
+ int loose)
{
struct diff_queue_struct *q = &diff_queued_diff;
int i;
- int result = diff_get_patch_id(options, sha1);
+ int result = diff_get_patch_id(options, sha1, loose);
for (i = 0; i < q->nr; i++)
diff_free_filepair(q->queue[i]);
diff --git a/diff.h b/diff.h
index 78b4091..b018aaf 100644
--- a/diff.h
+++ b/diff.h
@@ -320,7 +320,7 @@ extern int do_diff_cache(const unsigned char *, struct
diff_options *);
extern int run_diff_index(struct rev_info *revs, int cached);
extern int do_diff_cache(const unsigned char *, struct diff_options *);
-extern int diff_flush_patch_id(struct diff_options *, unsigned char *);
+extern int diff_flush_patch_id(struct diff_options *, unsigned char *, int
loose);
extern int diff_result_code(struct diff_options *, int);
diff --git a/patch-ids.c b/patch-ids.c
index bc8a28f..3a83ee6 100644
--- a/patch-ids.c
+++ b/patch-ids.c
@@ -5,7 +5,7 @@ static int commit_patch_id(struct commit *commit, struct
diff_options *options,
#include "patch-ids.h"
static int commit_patch_id(struct commit *commit, struct diff_options *options,
- unsigned char *sha1)
+ unsigned char *sha1, int loose)
{
if (commit->parents)
diff_tree_sha1(commit->parents->item->object.sha1,
@@ -13,27 +13,9 @@ static int commit_patch_id(struct commit *commit, struct
diff_options *options,
else
diff_root_tree_sha1(commit->object.sha1, "", options);
diffcore_std(options);
- return diff_flush_patch_id(options, sha1);
+ return diff_flush_patch_id(options, sha1, loose);
}
-static const unsigned char *patch_id_access(size_t index, void *table)
-{
- struct patch_id **id_table = table;
- return id_table[index]->patch_id;
-}
-
-static int patch_pos(struct patch_id **table, int nr, const unsigned char *id)
-{
- return sha1_pos(id, table, nr, patch_id_access);
-}
-
-#define BUCKET_SIZE 190 /* 190 * 21 = 3990, with slop close enough to 4K */
-struct patch_id_bucket {
- struct patch_id_bucket *next;
- int nr;
- struct patch_id bucket[BUCKET_SIZE];
-};
-
int init_patch_ids(struct patch_ids *ids)
{
memset(ids, 0, sizeof(*ids));
@@ -43,56 +25,83 @@ static struct patch_id *add_commit(struct commit *commit,
return 0;
}
+static int free_each_patch_id(void *patch_id, void *data)
+{
+ free(patch_id);
+ return 0;
+}
+
int free_patch_ids(struct patch_ids *ids)
{
- struct patch_id_bucket *next, *patches;
-
- free(ids->table);
- for (patches = ids->patches; patches; patches = next) {
- next = patches->next;
- free(patches);
- }
+ for_each_hash(&ids->table, free_each_patch_id, NULL);
+ free_hash(&ids->table);
return 0;
}
+static inline unsigned long hash_sha1(const unsigned char *sha1)
+{
+ unsigned int hash;
+ memcpy(&hash, sha1, sizeof(hash));
+ return hash;
+}
+
static struct patch_id *add_commit(struct commit *commit,
struct patch_ids *ids,
int no_add)
{
- struct patch_id_bucket *bucket;
- struct patch_id *ent;
- unsigned char sha1[20];
- int pos;
+ struct patch_id *p;
+ unsigned char loose[20], strict[20];
+ unsigned long hash;
+ void **pos;
- if (commit_patch_id(commit, &ids->diffopts, sha1))
+ if (commit_patch_id(commit, &ids->diffopts, loose, 1))
return NULL;
- pos = patch_pos(ids->table, ids->nr, sha1);
- if (0 <= pos)
- return ids->table[pos];
+ hash = hash_sha1(loose);
+
+ p = lookup_hash(hash, &ids->table);
+ for (; p; p = p->next) {
+ /* Skip collisions from our reduced hash. */
+ if (hashcmp(loose, p->loose))
+ continue;
+
+ /*
+ * We have a real loose match; lazily load and cache the strict
+ * id to compare.
+ */
+ if (is_null_sha1(p->strict)) {
+ if (commit_patch_id(p->commit, &ids->diffopts,
+ p->strict, 0))
+ return NULL;
+ }
+ if (commit_patch_id(commit, &ids->diffopts, strict, 0))
+ return NULL;
+
+ /*
+ * If the strict ones match, we do not need to look farther;
+ * the patch-id is here.
+ */
+ if (!hashcmp(strict, p->strict))
+ return p;
+ }
+
+ /*
+ * Otherwise, we may have a loose but not strict match, or even no
+ * loose match at all. Now we can add the new entry (or return failure
+ * to look it up).
+ */
if (no_add)
return NULL;
- pos = -1 - pos;
+ p = xcalloc(1, sizeof(*p));
+ p->commit = commit;
+ hashcpy(p->loose, loose);
- bucket = ids->patches;
- if (!bucket || (BUCKET_SIZE <= bucket->nr)) {
- bucket = xcalloc(1, sizeof(*bucket));
- bucket->next = ids->patches;
- ids->patches = bucket;
+ pos = insert_hash(hash, p, &ids->table);
+ if (pos) {
+ p->next = *pos;
+ *pos = p;
}
- ent = &bucket->bucket[bucket->nr++];
- hashcpy(ent->patch_id, sha1);
-
- if (ids->alloc <= ids->nr) {
- ids->alloc = alloc_nr(ids->nr);
- ids->table = xrealloc(ids->table, sizeof(ent) * ids->alloc);
- }
- if (pos < ids->nr)
- memmove(ids->table + pos + 1, ids->table + pos,
- sizeof(ent) * (ids->nr - pos));
- ids->nr++;
- ids->table[pos] = ent;
- return ids->table[pos];
+ return p;
}
struct patch_id *has_commit_patch_id(struct commit *commit,
diff --git a/patch-ids.h b/patch-ids.h
index c8c7ca1..c40ff39 100644
--- a/patch-ids.h
+++ b/patch-ids.h
@@ -2,15 +2,16 @@ struct patch_ids {
#define PATCH_IDS_H
struct patch_id {
- unsigned char patch_id[20];
- char seen;
+ struct commit *commit;
+ unsigned char loose[20];
+ unsigned char strict[20];
+ unsigned seen:1;
+ struct patch_id *next;
};
struct patch_ids {
struct diff_options diffopts;
- int nr, alloc;
- struct patch_id **table;
- struct patch_id_bucket *patches;
+ struct hash_table table;
};
int init_patch_ids(struct patch_ids *);
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