Package: debhelper
Version: 7.4.19
Severity: minor
Hi,
With the introduction of dh(1), many packages now use it, including lintian
for its testsuite. However, it comes with a great performance penalty compared
to just "using what is needed."
While taking a look at what makes debhelper very slow I noticed it calls dpkg-
architecture many times per package (66 times for the majority of the
packages).
Attached patch reduces the number of calls to dpkg-architecture to 36 for the
majority of the packages. It is a small improvement but I believe there are
other things that could be done to reduce the number of calls to dpkg-
architecture and to speed up debhelper in general.
The two calls to dpkg-architecture debhelper used to make were taking ~0.23s
each. The single call to dpkg-architecture (without -q) takes ~0.24s, which
means there's more or less an improvement of 0.22 seconds per use of Dh_Lib's
buildarch() and buildos().
Cheers,
--
Raphael Geissert - Debian Developer
www.debian.org - get.debian.net
--- unpacked/usr/share/perl5/Debian/Debhelper/Dh_Lib.pm 2010-04-26 18:47:52.000000000 -0500
+++ /usr/share/perl5/Debian/Debhelper/Dh_Lib.pm 2010-05-09 00:16:21.000000000 -0500
@@ -606,11 +606,23 @@
return 0;
}
-sub dpkg_architecture_value {
- my $var = shift;
- my $value=`dpkg-architecture -q$var` || error("dpkg-architecture failed");
- chomp $value;
- return $value;
+{
+ my %dpkg_arch_output;
+ sub dpkg_architecture_value {
+ my $var = shift;
+ local $_;
+ if (!exists($dpkg_arch_output{$var})) {
+ open(PIPE, '-|', 'dpkg-architecture')
+ or error("dpkg-architecture failed");
+ while (<PIPE>) {
+ my ($k, $v) = split(/=/);
+ chomp $v;
+ $dpkg_arch_output{$k} = $v;
+ }
+ close(PIPE);
+ }
+ return $dpkg_arch_output{$var};
+ }
}
# Returns the build architecture. (Memoized)
