From mboxrd@z Thu Jan 1 00:00:00 1970 From: Moritz Wilhelmy Date: Mon, 05 Sep 2011 11:56:03 +0000 Subject: [mlmmj] read(2) syscall bloat Message-Id: <20110905115603.GC22957@barfooze.de> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: mlmmj@mlmmj.org Hello, mlmmj currently does a read(2) system call for every single byte it reads from a file descriptor. This is unnecessarily inefficient and slow. Strace output is similar to the following: open("/var/spool/mlmmj/foo/control/listaddress", O_RDONLY) = 4 read(4, "f", 1) = 1 read(4, "o", 1) = 1 read(4, "o", 1) = 1 read(4, "@", 1) = 1 read(4, "l", 1) = 1 read(4, "i", 1) = 1 read(4, "s", 1) = 1 read(4, "t", 1) = 1 read(4, "s", 1) = 1 read(4, ".", 1) = 1 read(4, "e", 1) = 1 read(4, "x", 1) = 1 read(4, "a", 1) = 1 read(4, "m", 1) = 1 read(4, "p", 1) = 1 read(4, "l", 1) = 1 read(4, "e", 1) = 1 read(4, ".", 1) = 1 read(4, "c", 1) = 1 read(4, "o", 1) = 1 read(4, "m", 1) = 1 read(4, "\n", 1) = 1 close(4) = 0 Given that there is a getline(3) function in POSIX.1-2008, shouldn't it be possible to retire mygetline? I've previously posted this issue to the musl mailing list [1], which has an "anti-bloat side project", but I've been putting the mail to this list off. I don't see where any of Rich's arguments from [2] apply. Can anyone please explain why it was done this way in the first place? [1] http://www.openwall.com/lists/musl/2011/08/16/8 [2] http://www.openwall.com/lists/musl/2011/08/16/11 Moritz