Gentoo Archives: gentoo-project

From: Kent Fredric <kentnl@g.o>
To: gentoo-project@l.g.o
Subject: Re: [gentoo-project] RFC: Dropping rsync as a tree distribution method
Date: Thu, 20 Dec 2018 01:26:30
Message-Id: 20181220142603.25feb174@katipo2.lan
In Reply to: Re: [gentoo-project] RFC: Dropping rsync as a tree distribution method by Rich Freeman
1 On Sun, 16 Dec 2018 06:34:07 -0500
2 Rich Freeman <rich0@g.o> wrote:
4 > My guess is that it will
5 > also cost more IO server-side than rsync,
7 Surely that's dependent on how much of the rsync mirror is retained in
8 the VFS cache, and how efficiently the server in question avoids paging.
10 To the best of my understanding, server-side of rsync requires IO on
11 *thousands* of files, (lots of stat, open(), checksum), whereas
12 server-side for git can be reduced to only a handful of large files
13 (packs).
15 Even if we assume in both cases everything needed fits in VFS cache,
16 the rsync option still has reams of stat and open syscalls, that the
17 git option avoids, surely.
19 ( My observations made with vmtouch indicate that git doesn't even need
20 to load the entire pack into memory for a large majority of operations )