Export took a day

Performance is good/fast on smaller set of ,v-files, but seems to increase in super-quadratic manner. I converted a set of 16000 files and it took 26 hours. Disk and memory space was good at this time and CPU was 100% most of the time.

Version: cvs-fast-export: version 1.47 OS-Version: Linux 4.14.35-1844.2.5.el7uek.x86_64 #2 (closed) SMP Mon Feb 4 18:24:45 PST 2019 x86_64 x86_64 x86_64 GNU/Linux Libs: ldd which cvs-fast-export linux-vdso.so.1 => (0x00007fffb69ee000) libpthread.so.0 => /lib64/libpthread.so.0 (0x00007f97416f4000) libc.so.6 => /lib64/libc.so.6 (0x00007f9741327000) /lib64/ld-linux-x86-64.so.2 (0x00007f9741910000)