Currently git blame has a big problem finding copies and moves when you split up a big file into smaller ones. One example in the git repository is 2cf565c, which split the documentation into smaller files.
In 582aa00 XDF_NEED_MINIMAL was removed as the default for performance reasons, mainly for diff and rebase, but blame was also changed. In 059a500 the problem with blame was noticed and the flag --minimal was introduced. However this flag is not documented and it is not possible to set when using "git gui blame". Setting XDF_NEED_MINIMAL as default has a small performance impact when you run on a file with few modifications. However, if you run it on a file with a bigger number of modifications, the performance impact is small enough to not be noticable. ((2cf565c...))$ time PAGER=cat git blame -C -M Documentation/git-ls-files.txt > /dev/null real 0m0.003s user 0m0.002s sys 0m0.000s ((2cf565c...))$ time PAGER=cat git blame --minimal -C -M Documentation/git-ls-files.txt > /dev/null real 0m0.010s user 0m0.009s sys 0m0.000s ((2cf565c...))$ time PAGER=cat git blame -C -C -C -M Documentation/git-ls-files.txt > /dev/null real 0m0.010s user 0m0.010s sys 0m0.000s ((2cf565c...))$ time PAGER=cat git blame --minimal -C -C -C -M Documentation/git-ls-files.txt > /dev/null real 0m0.028s user 0m0.027s sys 0m0.000s (master)$ time PAGER=cat git blame -C -C -C -M Documentation/git-ls-files.txt > /dev/null real 0m2.338s user 0m2.283s sys 0m0.056s (master)$ time PAGER=cat git blame --minimal -C -C -C -M Documentation/git-ls-files.txt > /dev/null real 0m2.355s user 0m2.285s sys 0m0.069s (master)$ time PAGER=cat git blame -C -M cache.h > /dev/null real 0m1.755s user 0m1.730s sys 0m0.024s (master)$ time PAGER=cat git blame --minimal -C -M cache.h > /dev/null real 0m1.785s user 0m1.770s sys 0m0.014s (master)$ time PAGER=cat git blame -C -C -C -M cache.h > /dev/null real 0m31.515s user 0m30.810s sys 0m0.684s (master)$ time PAGER=cat git blame --minimal -C -C -C -M cache.h > /dev/null real 0m31.504s user 0m30.885s sys 0m0.598s Signed-off-by: Michael Andreen <h...@ruin.nu> --- Additional measurements attached, the variation is fairly small. The --minimal flag is still there, but didn't want to break scripts depending on it. builtin/blame.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/builtin/blame.c b/builtin/blame.c index e5b5d71..0e7ebd0 100644 --- a/builtin/blame.c +++ b/builtin/blame.c @@ -42,7 +42,7 @@ static int show_root; static int reverse; static int blank_boundary; static int incremental; -static int xdl_opts; +static int xdl_opts = XDF_NEED_MINIMAL; static int abbrev = -1; static int no_whole_file_rename; -- 1.8.3.2
(master)$ time PAGER=cat git blame -C -M cache.h > /dev/null real 0m1.767s user 0m1.747s sys 0m0.018s (master)$ time PAGER=cat git blame -C -M cache.h > /dev/null real 0m1.755s user 0m1.730s sys 0m0.024s (master)$ time PAGER=cat git blame -C -M cache.h > /dev/null real 0m1.784s user 0m1.757s sys 0m0.025s (master)$ time PAGER=cat git blame --minimal -C -M cache.h > /dev/null real 0m1.813s user 0m1.797s sys 0m0.014s (master)$ time PAGER=cat git blame --minimal -C -M cache.h > /dev/null real 0m1.790s user 0m1.770s sys 0m0.018s (master)$ time PAGER=cat git blame --minimal -C -M cache.h > /dev/null real 0m1.785s user 0m1.770s sys 0m0.014s (master)$ time PAGER=cat git blame --minimal -C -M cache.h > /dev/null real 0m1.794s user 0m1.770s sys 0m0.022s (master)$ time PAGER=cat git blame -C -C -C -M cache.h > /dev/null real 0m31.515s user 0m30.810s sys 0m0.684s (master)$ time PAGER=cat git blame -C -C -C -M cache.h > /dev/null real 0m31.594s user 0m30.879s sys 0m0.695s (master)$ time PAGER=cat git blame --minimal -C -C -C -M cache.h > /dev/null real 0m31.666s user 0m31.054s sys 0m0.591s (master)$ time PAGER=cat git blame --minimal -C -C -C -M cache.h > /dev/null real 0m31.504s user 0m30.885s sys 0m0.598s (master)$ time PAGER=cat git blame -C -C -C -M Documentation/git-ls-files.txt > /dev/null real 0m2.355s user 0m2.319s sys 0m0.035s (master)$ time PAGER=cat git blame -C -C -C -M Documentation/git-ls-files.txt > /dev/null real 0m2.352s user 0m2.292s sys 0m0.059s (master)$ time PAGER=cat git blame -C -C -C -M Documentation/git-ls-files.txt > /dev/null real 0m2.354s user 0m2.312s sys 0m0.040s (master)$ time PAGER=cat git blame -C -C -C -M Documentation/git-ls-files.txt > /dev/null real 0m2.338s user 0m2.283s sys 0m0.056s (master)$ time PAGER=cat git blame --minimal -C -C -C -M Documentation/git-ls-files.txt > /dev/null real 0m2.376s user 0m2.302s sys 0m0.071s (master)$ time PAGER=cat git blame --minimal -C -C -C -M Documentation/git-ls-files.txt > /dev/null real 0m2.362s user 0m2.312s sys 0m0.049s (master)$ time PAGER=cat git blame --minimal -C -C -C -M Documentation/git-ls-files.txt > /dev/null real 0m2.360s user 0m2.301s sys 0m0.057s (master)$ time PAGER=cat git blame --minimal -C -C -C -M Documentation/git-ls-files.txt > /dev/null real 0m2.355s user 0m2.285s sys 0m0.069s --------------------------------------------------- ((2cf565c...))$ time PAGER=cat git blame -C -M Documentation/git-ls-files.txt > /dev/null real 0m0.003s user 0m0.002s sys 0m0.000s ((2cf565c...))$ time PAGER=cat git blame -C -M Documentation/git-ls-files.txt > /dev/null real 0m0.003s user 0m0.003s sys 0m0.000s ((2cf565c...))$ time PAGER=cat git blame -C -M Documentation/git-ls-files.txt > /dev/null real 0m0.004s user 0m0.003s sys 0m0.001s ((2cf565c...))$ time PAGER=cat git blame -C -M Documentation/git-ls-files.txt > /dev/null real 0m0.004s user 0m0.003s sys 0m0.001s ((2cf565c...))$ time PAGER=cat git blame -C -M Documentation/git-ls-files.txt > /dev/null real 0m0.003s user 0m0.002s sys 0m0.001s ((2cf565c...))$ time PAGER=cat git blame --minimal -C -M Documentation/git-ls-files.txt > /dev/null real 0m0.010s user 0m0.009s sys 0m0.000s ((2cf565c...))$ time PAGER=cat git blame --minimal -C -M Documentation/git-ls-files.txt > /dev/null real 0m0.011s user 0m0.010s sys 0m0.001s ((2cf565c...))$ time PAGER=cat git blame --minimal -C -M Documentation/git-ls-files.txt > /dev/null real 0m0.012s user 0m0.012s sys 0m0.000s ((2cf565c...))$ time PAGER=cat git blame --minimal -C -M Documentation/git-ls-files.txt > /dev/null real 0m0.011s user 0m0.011s sys 0m0.000s ((2cf565c...))$ time PAGER=cat git blame -C -C -C -M Documentation/git-ls-files.txt > /dev/null real 0m0.008s user 0m0.007s sys 0m0.002s ((2cf565c...))$ time PAGER=cat git blame -C -C -C -M Documentation/git-ls-files.txt > /dev/null real 0m0.011s user 0m0.011s sys 0m0.000s ((2cf565c...))$ time PAGER=cat git blame -C -C -C -M Documentation/git-ls-files.txt > /dev/null real 0m0.010s user 0m0.010s sys 0m0.000s ((2cf565c...))$ time PAGER=cat git blame -C -C -C -M Documentation/git-ls-files.txt > /dev/null real 0m0.010s user 0m0.009s sys 0m0.000s ((2cf565c...))$ time PAGER=cat git blame --minimal -C -C -C -M Documentation/git-ls-files.txt > /dev/null real 0m0.028s user 0m0.024s sys 0m0.003s ((2cf565c...))$ time PAGER=cat git blame --minimal -C -C -C -M Documentation/git-ls-files.txt > /dev/null real 0m0.032s user 0m0.029s sys 0m0.002s ((2cf565c...))$ time PAGER=cat git blame --minimal -C -C -C -M Documentation/git-ls-files.txt > /dev/null real 0m0.027s user 0m0.025s sys 0m0.001s ((2cf565c...))$ time PAGER=cat git blame --minimal -C -C -C -M Documentation/git-ls-files.txt > /dev/null real 0m0.028s user 0m0.027s sys 0m0.000s