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author | Dan McGee <dan@archlinux.org> | 2010-12-14 19:36:02 +0100 |
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committer | Dan McGee <dan@archlinux.org> | 2010-12-14 19:36:02 +0100 |
commit | 919bb6c9e00820c3930067b5985a246a455bef57 (patch) | |
tree | aff800a6e65184a873c02bcb908196b0022047c5 /lib/libalpm/util.h | |
parent | c2a73ba989fffb59c1b8ac7edb265a996dfc184d (diff) | |
download | pacman-919bb6c9e00820c3930067b5985a246a455bef57.tar.gz pacman-919bb6c9e00820c3930067b5985a246a455bef57.tar.xz |
Used hashed package name in _alpm_pkg_find
This results in huge gains to a lot of our codepaths since this is the most
frequent method of random access to packages in a list. The gains are seen
in both profiling and real life.
$ pacman -Sii zvbi
real: 0.41 sec -> 0.32 sec
strcmp: 16,669,760 calls -> 473,942 calls
_alpm_pkg_find: 52.73% -> 26.31% of time
$ pacman -Su (no upgrades found)
real: 0.40 sec -> 0.50 sec
strcmp: 19,497,226 calls -> 524,097 calls
_alpm_pkg_find: 52.36% -> 26.15% of time
There is some minor risk with this patch, but most of it should be avoided
by falling back to strcmp() if we encounter a package with a '0' hash value
(which we should not via any existing code path). We also do a strcmp once
hash values match to ensure against hash collisions. The risk left is that a
package name is modified once it was originally set, but the hash value is
left alone. That would probably result in a lot of other problems anyway.
Signed-off-by: Dan McGee <dan@archlinux.org>
Diffstat (limited to 'lib/libalpm/util.h')
0 files changed, 0 insertions, 0 deletions