Terrible bad performance for it blame --date=iso -C -C master -- <file>

Hi!

I was running "vc-annotate" in Emacs for a file from a large repository (>40000 files, a big percentage being binary, about 10 commits). For the first file the result was presented rather soon, but for a second file the command did not finish even after about 10 minutes!

The file in question is a rather short text file (124 kB), and according to git log it has one commit.

While being bored, I did an strace of the command to find out that a huge number of files is inspected.

I'm using git of openSUSE LEap 42.2 (git-2.10.2-3.1.x86_64).

Here's the stat of the process:

% cat /proc/6307/stat 6307 (git) R 6189 6307 6307 0 -1 4194304 30514692 0 1860 0 142035 6333 0 0 20 0 1 0 14519800 5850595328 391884 18446744073709551615 4194304 6038988 140726752300720 140726752293728 5549816 0 0 67108864 0 0 0 0 17 2 0 0 28211 0 0 8138160 8173100 9625600 140726752306005 140726752306072 140726752306072 140726752309227 0

Regards, Ulrich