On Wed, Jun 28, 2006 at 11:58:49PM -0400, Jeff King wrote:
> about 2.7M. The linux-2.6 cache is 22M.
> [...]
> - correctness. Currently the code uses the output of try_delta for
> negative caching. Should the cache checking be moved inside try_delta
> instead? This would give more control over which reasons to mark a
I tried moving the cache check/mark to wrap the call to create_delta in
try_delta. The speedup is the same (since all of the CPU time is spent
in create_delta anyway), and the linux-2.6 cache size dropped to 18M.
I also think this is probably more correct (it ignores every reason not
to delta EXCEPT create_delta failing).
The distribution of the window parameter 'j' is similarly uniform:
44900 j=2
44907 j=3
44943 j=1
45001 j=4
45014 j=5
45023 j=6
45063 j=7
45158 j=8
45288 j=9
45466 j=10
Patch on top of my other one is below.
-Peff
-- >8 --
pack-objects: move delta-cache check/mark closer to create_delta
Signed-off-by: Jeff King <peff@xxxxxxxx>
---
pack-objects.c | 15 ++++++---------
1 files changed, 6 insertions(+), 9 deletions(-)
diff --git a/pack-objects.c b/pack-objects.c
index 46b9775..83ccc8a 100644
--- a/pack-objects.c
+++ b/pack-objects.c
@@ -1014,9 +1014,13 @@ static int try_delta(struct unpacked *tr
if (sizediff >= max_size)
return 0;
+ if (delta_cache_check(src->entry->sha1, trg->entry->sha1))
+ return 0;
delta_buf = create_delta(src_index, trg->data, size, &delta_size, max_size);
- if (!delta_buf)
+ if (!delta_buf) {
+ delta_cache_mark(src->entry->sha1, trg->entry->sha1);
return 0;
+ }
trg_entry->delta = src_entry;
trg_entry->delta_size = delta_size;
@@ -1084,21 +1088,14 @@ static void find_deltas(struct object_en
j = window;
while (--j > 0) {
unsigned int other_idx = idx + j;
- int r;
struct unpacked *m;
if (other_idx >= window)
other_idx -= window;
m = array + other_idx;
if (!m->entry)
break;
- if (delta_cache_check(n->entry->sha1, m->entry->sha1))
- continue;
- r = try_delta(n, m, m->index, depth);
- if (r < 0)
+ if (try_delta(n, m, m->index, depth) < 0)
break;
- if (r == 0)
- delta_cache_mark(n->entry->sha1,
- m->entry->sha1);
}
/* if we made n a delta, and if n is already at max
* depth, leaving it in the window is pointless. we
--
1.4.1.rc1.g0458-dirty
-
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