From 950a234cbd781021d69fcfaa40ab6fd258b1d917 Mon Sep 17 00:00:00 2001 From: Jeff Hostetler Date: Fri, 14 Apr 2017 19:51:52 +0000 Subject: [PATCH] string-list: use ALLOC_GROW macro when reallocing string_list Use ALLOC_GROW() macro when reallocing a string_list array rather than simply increasing it by 32. This is a performance optimization. During status on a very large repo and there are many changes, a significant percentage of the total run time is spent reallocing the wt_status.changes array. This change decreases the time in wt_status_collect_changes_worktree() from 125 seconds to 45 seconds on my very large repository. This produced a modest gain on my 1M file artificial repo, but broke even on linux.git. Test HEAD^^ HEAD --------------------------------------------------------------------------------------- 0005.2: read-tree status br_ballast (1000001) 8.29(5.62+2.62) 8.22(5.57+2.63) -0.8% Signed-off-by: Jeff Hostetler Signed-off-by: Junio C Hamano --- string-list.c | 5 +---- t/perf/p0005-status.sh | 49 ++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 50 insertions(+), 4 deletions(-) create mode 100755 t/perf/p0005-status.sh diff --git a/string-list.c b/string-list.c index 8c83cac189..1e27d9cec3 100644 --- a/string-list.c +++ b/string-list.c @@ -41,10 +41,7 @@ static int add_entry(int insert_at, struct string_list *list, const char *string if (exact_match) return -1 - index; - if (list->nr + 1 >= list->alloc) { - list->alloc += 32; - REALLOC_ARRAY(list->items, list->alloc); - } + ALLOC_GROW(list->items, list->nr+1, list->alloc); if (index < list->nr) memmove(list->items + index + 1, list->items + index, (list->nr - index) diff --git a/t/perf/p0005-status.sh b/t/perf/p0005-status.sh new file mode 100755 index 0000000000..0b0aa9858f --- /dev/null +++ b/t/perf/p0005-status.sh @@ -0,0 +1,49 @@ +#!/bin/sh +# +# This test measures the performance of various read-tree +# and status operations. It is primarily interested in +# the algorithmic costs of index operations and recursive +# tree traversal -- and NOT disk I/O on thousands of files. + +test_description="Tests performance of read-tree" + +. ./perf-lib.sh + +test_perf_default_repo + +# If the test repo was generated by ./repos/many-files.sh +# then we know something about the data shape and branches, +# so we can isolate testing to the ballast-related commits +# and setup sparse-checkout so we don't have to populate +# the ballast files and directories. +# +# Otherwise, we make some general assumptions about the +# repo and consider the entire history of the current +# branch to be the ballast. + +test_expect_success "setup repo" ' + if git rev-parse --verify refs/heads/p0006-ballast^{commit} + then + echo Assuming synthetic repo from many-files.sh + git branch br_base master + git branch br_ballast p0006-ballast + git config --local core.sparsecheckout 1 + cat >.git/info/sparse-checkout <<-EOF + /* + !ballast/* + EOF + else + echo Assuming non-synthetic repo... + git branch br_base $(git rev-list HEAD | tail -n 1) + git branch br_ballast HEAD + fi && + git checkout -q br_ballast && + nr_files=$(git ls-files | wc -l) +' + +test_perf "read-tree status br_ballast ($nr_files)" ' + git read-tree HEAD && + git status +' + +test_done