From: "Elijah Newren via GitGitGadget" <gitgitgadget@gmail.com>
To: git@vger.kernel.org
Cc: Derrick Stolee <dstolee@microsoft.com>,
Jonathan Tan <jonathantanmy@google.com>,
Taylor Blau <me@ttaylorr.com>, Junio C Hamano <gitster@pobox.com>,
Jeff King <peff@peff.net>, Karsten Blees <blees@dcon.de>,
Derrick Stolee <stolee@gmail.com>,
Elijah Newren <newren@gmail.com>,
Elijah Newren <newren@gmail.com>,
Elijah Newren <newren@gmail.com>
Subject: [PATCH v2 1/2] diffcore-rename: no point trying to find a match better than exact
Date: Wed, 03 Feb 2021 20:03:46 +0000 [thread overview]
Message-ID: <770e894b4abdf24112fa51f963b6fce15be942c1.1612382628.git.gitgitgadget@gmail.com> (raw)
In-Reply-To: <pull.842.v2.git.1612382628.gitgitgadget@gmail.com>
From: Elijah Newren <newren@gmail.com>
diffcore_rename() had some code to avoid having destination paths that
already had an exact rename detected from being re-checked for other
renames. Source paths, however, were re-checked because we wanted to
allow the possibility of detecting copies. But if copy detection isn't
turned on, then this merely amounts to attempting to find a
better-than-exact match, which naturally ends up being an expensive
no-op. In particular, copy detection is never turned on by the merge
machinery.
For the testcases mentioned in commit 557ac0350d ("merge-ort: begin
performance work; instrument with trace2_region_* calls", 2020-10-28),
this change improves the performance as follows:
Before After
no-renames: 14.263 s ± 0.053 s 14.119 s ± 0.101 s
mega-renames: 5504.231 s ± 5.150 s 1802.044 s ± 0.828 s
just-one-mega: 158.534 s ± 0.498 s 51.391 s ± 0.028 s
Signed-off-by: Elijah Newren <newren@gmail.com>
---
diffcore-rename.c | 20 ++++++++++++++------
1 file changed, 14 insertions(+), 6 deletions(-)
diff --git a/diffcore-rename.c b/diffcore-rename.c
index 8fe6c9384bc..8b118628b4e 100644
--- a/diffcore-rename.c
+++ b/diffcore-rename.c
@@ -463,9 +463,11 @@ void diffcore_rename(struct diff_options *options)
struct diff_score *mx;
int i, j, rename_count, skip_unmodified = 0;
int num_destinations, dst_cnt;
+ int num_sources, want_copies;
struct progress *progress = NULL;
trace2_region_enter("diff", "setup", options->repo);
+ want_copies = (detect_rename == DIFF_DETECT_COPY);
if (!minimum_score)
minimum_score = DEFAULT_RENAME_SCORE;
@@ -502,7 +504,7 @@ void diffcore_rename(struct diff_options *options)
p->one->rename_used++;
register_rename_src(p);
}
- else if (detect_rename == DIFF_DETECT_COPY) {
+ else if (want_copies) {
/*
* Increment the "rename_used" score by
* one, to indicate ourselves as a user.
@@ -532,12 +534,15 @@ void diffcore_rename(struct diff_options *options)
* files still remain as options for rename/copies!)
*/
num_destinations = (rename_dst_nr - rename_count);
+ num_sources = rename_src_nr;
+ if (!want_copies)
+ num_sources -= rename_count;
/* All done? */
- if (!num_destinations)
+ if (!num_destinations || !num_sources)
goto cleanup;
- switch (too_many_rename_candidates(num_destinations, rename_src_nr,
+ switch (too_many_rename_candidates(num_destinations, num_sources,
options)) {
case 1:
goto cleanup;
@@ -553,7 +558,7 @@ void diffcore_rename(struct diff_options *options)
if (options->show_rename_progress) {
progress = start_delayed_progress(
_("Performing inexact rename detection"),
- (uint64_t)num_destinations * (uint64_t)rename_src_nr);
+ (uint64_t)num_destinations * (uint64_t)num_sources);
}
mx = xcalloc(st_mult(NUM_CANDIDATE_PER_DST, num_destinations),
@@ -573,6 +578,9 @@ void diffcore_rename(struct diff_options *options)
struct diff_filespec *one = rename_src[j].p->one;
struct diff_score this_src;
+ if (one->rename_used && !want_copies)
+ continue;
+
if (skip_unmodified &&
diff_unmodified_pair(rename_src[j].p))
continue;
@@ -594,7 +602,7 @@ void diffcore_rename(struct diff_options *options)
}
dst_cnt++;
display_progress(progress,
- (uint64_t)dst_cnt * (uint64_t)rename_src_nr);
+ (uint64_t)dst_cnt * (uint64_t)num_sources);
}
stop_progress(&progress);
@@ -602,7 +610,7 @@ void diffcore_rename(struct diff_options *options)
STABLE_QSORT(mx, dst_cnt * NUM_CANDIDATE_PER_DST, score_compare);
rename_count += find_renames(mx, dst_cnt, minimum_score, 0);
- if (detect_rename == DIFF_DETECT_COPY)
+ if (want_copies)
rename_count += find_renames(mx, dst_cnt, minimum_score, 1);
free(mx);
trace2_region_leave("diff", "inexact renames", options->repo);
--
gitgitgadget
next prev parent reply other threads:[~2021-02-03 20:06 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-03 5:49 [PATCH 0/2] Optimization batch 6: make full use of exact renames Elijah Newren via GitGitGadget
2021-02-03 5:49 ` [PATCH 1/2] diffcore-rename: no point trying to find a match better than exact Elijah Newren via GitGitGadget
2021-02-03 11:44 ` Derrick Stolee
2021-02-03 16:31 ` Elijah Newren
2021-02-03 18:46 ` Junio C Hamano
2021-02-03 19:10 ` Elijah Newren
2021-02-03 5:49 ` [PATCH 2/2] diffcore-rename: filter rename_src list when possible Elijah Newren via GitGitGadget
[not found] ` <13feb106-c3a7-a26d-0e6e-013aa45c58d4@gmail.com>
2021-02-03 17:12 ` Elijah Newren
2021-02-03 19:12 ` Junio C Hamano
2021-02-03 19:19 ` Elijah Newren
2021-02-03 20:03 ` [PATCH v2 0/2] Optimization batch 6: make full use of exact renames Elijah Newren via GitGitGadget
2021-02-03 20:03 ` Elijah Newren via GitGitGadget [this message]
2021-02-03 20:03 ` [PATCH v2 2/2] diffcore-rename: filter rename_src list when possible Elijah Newren via GitGitGadget
2021-02-13 1:04 ` Junio C Hamano
2021-02-13 4:24 ` Elijah Newren
2021-02-13 1:06 ` Junio C Hamano
2021-02-13 4:43 ` Elijah Newren
2021-02-03 21:56 ` [PATCH v2 0/2] Optimization batch 6: make full use of exact renames Junio C Hamano
2021-02-03 23:06 ` Elijah Newren
2021-02-03 23:26 ` Junio C Hamano
2021-02-03 23:36 ` Jeff King
2021-02-04 0:05 ` Elijah Newren
2021-02-14 7:34 ` [PATCH v3 " Elijah Newren via GitGitGadget
2021-02-14 7:35 ` [PATCH v3 1/2] diffcore-rename: no point trying to find a match better than exact Elijah Newren via GitGitGadget
2021-02-14 7:35 ` [PATCH v3 2/2] diffcore-rename: filter rename_src list when possible Elijah Newren via GitGitGadget
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