[pacman-dev] alpm_list: missing quick access to last element

[Dan McGee]

On 3/4/07, Jürgen Hötzel <juergen at hoetzel.info> wrote:
> Hi,
>
> I'm back to pacman-dev, and just just found this out profiling pacman-cvs
> (pacman -Ss test):
>
> ...
> -----------------------------------------------
>                 0.12    0.00   13785/13785       alpm_list_add [7]
> [8]     42.9    0.12    0.00   13785         alpm_list_last [8]
> -----------------------------------------------
> ...
>
> alpm_list_last is eating up 42.9% CPU-time on my slow epia system. This is
> due the missing "last element hint" which speeded up the add operation
> before aaron introduced the public alpm_list type two months ago. I
> consider adding the "last element" member again. Any objections?

Yeah, something like this definitely needs to be done. HOWEVER, let's
hold off until post-3.0.0 release. We are in bugfix-only mode for the
time being, and this is more than a bugfix. If you want to patch it
locally, then we can probably get it into 3.0.1, but I really want to
stick with this bugfix-only mentality otherwise we will just keep
finding things we want to fix and never stay quite stable enough to
release.

By the way, we are thinking of changing some of the data structures
used, and we have at least glanced at these things: kernel-style
linked lists <http://isis.poly.edu/kulesh/stuff/src/klist/>, a
hash-table package cache, and something along this line-
<http://tech.inhelsinki.nl/d_store/>.

-Dan