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git-pickaxe: optimize by avoiding repeated read_sha1_file().
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It turns out that pickaxe reads the same blob repeatedly while
blame can reuse the blob already read for the parent when
handling a child commit when it's parent's turn to pass its
blame to the grandparent.  Have a cache in the origin structure
to keep the blob there, which will be garbage collected when the
origin loses the last reference to it.

Signed-off-by: Junio C Hamano <junkio@cox.net>
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Junio C Hamano committed Nov 5, 2006
1 parent 2bc4547 commit c2e525d
Showing 1 changed file with 62 additions and 38 deletions.
100 changes: 62 additions & 38 deletions builtin-pickaxe.c
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Expand Up @@ -40,6 +40,11 @@ static int max_score_digits;
#define DEBUG 0
#endif

/* stats */
static int num_read_blob;
static int num_get_patch;
static int num_commits;

#define PICKAXE_BLAME_MOVE 01
#define PICKAXE_BLAME_COPY 02
#define PICKAXE_BLAME_COPY_HARDER 04
Expand All @@ -63,10 +68,25 @@ static unsigned blame_copy_score;
struct origin {
int refcnt;
struct commit *commit;
mmfile_t file;
unsigned char blob_sha1[20];
char path[FLEX_ARRAY];
};

static char *fill_origin_blob(struct origin *o, mmfile_t *file)
{
if (!o->file.ptr) {
char type[10];
num_read_blob++;
file->ptr = read_sha1_file(o->blob_sha1, type,
(unsigned long *)(&(file->size)));
o->file = *file;
}
else
*file = o->file;
return file->ptr;
}

static inline struct origin *origin_incref(struct origin *o)
{
if (o)
Expand All @@ -77,6 +97,8 @@ static inline struct origin *origin_incref(struct origin *o)
static void origin_decref(struct origin *o)
{
if (o && --o->refcnt <= 0) {
if (o->file.ptr)
free(o->file.ptr);
memset(o, 0, sizeof(*o));
free(o);
}
Expand Down Expand Up @@ -431,25 +453,14 @@ static struct patch *compare_buffer(mmfile_t *file_p, mmfile_t *file_o,
static struct patch *get_patch(struct origin *parent, struct origin *origin)
{
mmfile_t file_p, file_o;
char type[10];
char *blob_p, *blob_o;
struct patch *patch;

blob_p = read_sha1_file(parent->blob_sha1, type,
(unsigned long *) &file_p.size);
blob_o = read_sha1_file(origin->blob_sha1, type,
(unsigned long *) &file_o.size);
file_p.ptr = blob_p;
file_o.ptr = blob_o;
if (!file_p.ptr || !file_o.ptr) {
free(blob_p);
free(blob_o);
fill_origin_blob(parent, &file_p);
fill_origin_blob(origin, &file_o);
if (!file_p.ptr || !file_o.ptr)
return NULL;
}

patch = compare_buffer(&file_p, &file_o, 0);
free(blob_p);
free(blob_o);
num_get_patch++;
return patch;
}

Expand Down Expand Up @@ -784,20 +795,14 @@ static int find_move_in_parent(struct scoreboard *sb,
int last_in_target, made_progress;
struct blame_entry *e, split[3];
mmfile_t file_p;
char type[10];
char *blob_p;

last_in_target = find_last_in_target(sb, target);
if (last_in_target < 0)
return 1; /* nothing remains for this target */

blob_p = read_sha1_file(parent->blob_sha1, type,
(unsigned long *) &file_p.size);
file_p.ptr = blob_p;
if (!file_p.ptr) {
free(blob_p);
fill_origin_blob(parent, &file_p);
if (!file_p.ptr)
return 0;
}

made_progress = 1;
while (made_progress) {
Expand All @@ -814,7 +819,6 @@ static int find_move_in_parent(struct scoreboard *sb,
decref_split(split);
}
}
free(blob_p);
return 0;
}

Expand Down Expand Up @@ -900,8 +904,6 @@ static int find_copy_in_parent(struct scoreboard *sb,
struct diff_filepair *p = diff_queued_diff.queue[i];
struct origin *norigin;
mmfile_t file_p;
char type[10];
char *blob;
struct blame_entry this[3];

if (!DIFF_FILE_VALID(p->one))
Expand All @@ -912,9 +914,7 @@ static int find_copy_in_parent(struct scoreboard *sb,

norigin = get_origin(sb, parent, p->one->path);
hashcpy(norigin->blob_sha1, p->one->sha1);
blob = read_sha1_file(norigin->blob_sha1, type,
(unsigned long *) &file_p.size);
file_p.ptr = blob;
fill_origin_blob(norigin, &file_p);
if (!file_p.ptr)
continue;

Expand All @@ -925,7 +925,6 @@ static int find_copy_in_parent(struct scoreboard *sb,
this);
decref_split(this);
}
free(blob);
origin_decref(norigin);
}

Expand Down Expand Up @@ -953,6 +952,28 @@ static int find_copy_in_parent(struct scoreboard *sb,
return retval;
}

/* The blobs of origin and porigin exactly match, so everything
* origin is suspected for can be blamed on the parent.
*/
static void pass_whole_blame(struct scoreboard *sb,
struct origin *origin, struct origin *porigin)
{
struct blame_entry *e;

if (!porigin->file.ptr && origin->file.ptr) {
/* Steal its file */
porigin->file = origin->file;
origin->file.ptr = NULL;
}
for (e = sb->ent; e; e = e->next) {
if (cmp_suspect(e->suspect, origin))
continue;
origin_incref(porigin);
origin_decref(e->suspect);
e->suspect = porigin;
}
}

#define MAXPARENT 16

static void pass_blame(struct scoreboard *sb, struct origin *origin, int opt)
Expand Down Expand Up @@ -986,13 +1007,7 @@ static void pass_blame(struct scoreboard *sb, struct origin *origin, int opt)
if (!porigin)
continue;
if (!hashcmp(porigin->blob_sha1, origin->blob_sha1)) {
struct blame_entry *e;
for (e = sb->ent; e; e = e->next)
if (e->suspect == origin) {
origin_incref(porigin);
origin_decref(e->suspect);
e->suspect = porigin;
}
pass_whole_blame(sb, origin, porigin);
origin_decref(porigin);
goto finish;
}
Expand All @@ -1010,6 +1025,7 @@ static void pass_blame(struct scoreboard *sb, struct origin *origin, int opt)
}
}

num_commits++;
for (i = 0, parent = commit->parents;
i < MAXPARENT && parent;
parent = parent->next, i++) {
Expand Down Expand Up @@ -1068,7 +1084,8 @@ static void assign_blame(struct scoreboard *sb, struct rev_info *revs, int opt)

origin_incref(suspect);
commit = suspect->commit;
parse_commit(commit);
if (!commit->object.parsed)
parse_commit(commit);
if (!(commit->object.flags & UNINTERESTING) &&
!(revs->max_age != -1 && commit->date < revs->max_age))
pass_blame(sb, suspect, opt);
Expand Down Expand Up @@ -1735,6 +1752,7 @@ int cmd_pickaxe(int argc, const char **argv, const char *prefix)
die("no such path %s in %s", path, final_commit_name);

sb.final_buf = read_sha1_file(o->blob_sha1, type, &sb.final_buf_size);
num_read_blob++;
lno = prepare_lines(&sb);

if (bottom < 1)
Expand Down Expand Up @@ -1772,5 +1790,11 @@ int cmd_pickaxe(int argc, const char **argv, const char *prefix)
free(ent);
ent = e;
}

if (DEBUG) {
printf("num read blob: %d\n", num_read_blob);
printf("num get patch: %d\n", num_get_patch);
printf("num commits: %d\n", num_commits);
}
return 0;
}

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