Re: [PATCH] libdpkg: use mmap if available to parse package info files

[Jonathan Nieder <jrnieder@gmail.com>]

Guillem Jover wrote:

> But even then I think
> I'd just prefer switching the code to use chunked I/O instead, which
> should be as reliable, and use consistently way less memory at any
> given time.

Hmm, that basically means reverting commit 864e230e, since stdio
uses chunked I/O internally.

It would be interesting to try to figure out where the time went
there:

 . function call overhead for getc/varbufaddc loops
 . memory management when the field and value needed to grow
 . copying from I/O buffer to field/value buffers
 . locking for each getc call

Any tips for profiling this?  I would think the time spent here is
likely to be negligible in a typical dpkg run; ‘dselect update’ would
be the main place this matters.

Jonathan