Re: git-diff-tree -M performance regression in 'next'
- From
Junio C Hamano <junkio@cox.net>
- Date
- Mar 13, 2006, 00:42 UTC
- Message-ID
- <7vwtezw4ye.fsf@assigned-by-dhcp.cox.net>
- In-Reply-To
- <7vk6azcv9y.fsf@assigned-by-dhcp.cox.net>
Show 11 quoted lines
> Linus Torvalds <torvalds@osdl.org> writes: > >> On Sun, 12 Mar 2006, Junio C Hamano wrote: >>> >>> master : 130m virtual, 40m resident, (0major+12510minor) >>> 66.06user 0.07system 1:10.95elapsed >>> "next" : 150m virtual, 65m resident, (0major+49858minor) >>> 51.41user 0.45system 0.57.55elapsed >> >> Any way to fix that "4 times as many page misses, and 70% bigger rss?" >> thing? It looks like you're not very careful about your memory use.
"this" : 145m virtual, 57m resident, (0major+18855minor)
39.81user 0.28system 0:42.16elapsed50% more page misses, 45% bigger rss, 65% less usertime. Slowly getting there...
-- >8 -- [PATCH] diffcore-delta: make the hash a bit denser.
To reduce wasted memory, wait until the hash fills up more densely before we rehash. This reduces the working set size a bit further.
Signed-off-by: Junio C Hamano <junkio@cox.net>
---
diffcore-delta.c | 13 +++++++++---- diffcore-rename.c | 4 +++- 2 files changed, 12 insertions(+), 5 deletions(-)
af0b459589edaa77c51a892dd7dc44329634d253
diff --git a/diffcore-delta.c b/diffcore-delta.c index 471b98f..f8a7518 100644 --- a/diffcore-delta.c +++ b/diffcore-delta.c @@ -25,8 +25,12 @@ */ /* Wild guess at the initial hash size */ -#define INITIAL_HASH_SIZE 10 +#define INITIAL_HASH_SIZE 9 #define HASHBASE 65537 /* next_prime(2^16) */ +/* We leave more room in smaller hash but do not let it + * grow to have unused hole too much. + */ +#define INITIAL_FREE(sz_log2) ((1<<(sz_log2))*(sz_log2-3)/(sz_log2)) struct spanhash { unsigned long hashval; @@ -38,7 +42,8 @@ struct spanhash_top { struct spanhash data[FLEX_ARRAY]; }; -static struct spanhash *spanhash_find(struct spanhash_top *top, unsigned long hashval) +static struct spanhash *spanhash_find(struct spanhash_top *top, + unsigned long hashval) { int sz = 1 << top->alloc_log2; int bucket = hashval & (sz - 1); @@ -62,7 +67,7 @@ static struct spanhash_top *spanhash_reh new = xmalloc(sizeof(*orig) + sizeof(struct spanhash) * sz); new->alloc_log2 = orig->alloc_log2 + 1; - new->free = osz; + new->free = INITIAL_FREE(new->alloc_log2); memset(new->data, 0, sizeof(struct spanhash) * sz); for (i = 0; i < osz; i++) { struct spanhash *o = &(orig->data[i]); @@ -122,7 +127,7 @@ static struct spanhash_top *hash_chars(u i = INITIAL_HASH_SIZE; hash = xmalloc(sizeof(*hash) + sizeof(struct spanhash) * (1<<i)); hash->alloc_log2 = i; - hash->free = (1<<i)/2; + hash->free = INITIAL_FREE(i); memset(hash->data, 0, sizeof(struct spanhash) * (1<<i)); /* an 8-byte shift register made of accum1 and accum2. New diff --git a/diffcore-rename.c b/diffcore-rename.c index b80b432..8380049 100644 --- a/diffcore-rename.c +++ b/diffcore-rename.c @@ -307,8 +307,10 @@ void diffcore_rename(struct diff_options m->score = estimate_similarity(one, two, minimum_score); } + /* We do not need the text anymore */ free(two->cnt_data); - two->cnt_data = NULL; + free(two->data); + two->data = two->cnt_data = NULL; dst_cnt++; } /* cost matrix sorted by most to least similar pair */
-- 1.2.4.g3dcf