Control: tags -1 patch
On Thu, 01 Dec 2016 01:59:35 +0100 Simon Richter <s...@debian.org> wrote:
> Package: dpkg
> Version: 1.18.15
> Severity: minor
>
> Hi,
>
> when building the piglit package, the dpkg-shlibdeps invocations take
> upwards of 30 minutes (on an i7, building inside a tmpfs). Most of the
> time seems to be spent spawning several thousand instances of dpkg-query.
>
> Is there a way to speed this up, e.g. with a cache?
>
> Simon
>
> [...]
>
Hi,
I have written the following patch that may be worth applying. It
causes dpkg-shlibdeps to cache the result of get_control_path, which
results in a good speed improvement in my benchmark.
On the full piglit, it seems to reduce my runtime from about ~14m to ~2m
Thanks,
~Niels
From ff10b82e72b52c6af592f7dbda6d7964a155cb57 Mon Sep 17 00:00:00 2001
From: Niels Thykier <ni...@thykier.net>
Date: Sat, 1 Apr 2017 16:49:48 +0000
Subject: [PATCH 2/2] dpkg-shlibdeps: Cache get_control_path calls
It is basically a thin-wrapper around "dpkg-query --control-path" and
the repeated calls add up to quite a sum.
Results from a poor-mans performance test on ~90 ELF binaries from
piglit:
* BEFORE:
real 0m35.892s
user 0m15.652s
sys 0m18.584s
* AFTER:
real 0m10.884s
user 0m7.316s
sys 0m3.296s
Signed-off-by: Niels Thykier <ni...@thykier.net>
---
scripts/dpkg-shlibdeps.pl | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/scripts/dpkg-shlibdeps.pl b/scripts/dpkg-shlibdeps.pl
index 76031b91f..656e9930c 100755
--- a/scripts/dpkg-shlibdeps.pl
+++ b/scripts/dpkg-shlibdeps.pl
@@ -739,6 +739,8 @@ sub extract_from_shlibs {
return $dep;
}
+my %symbols_file_cache;
+
sub find_symbols_file {
my ($pkg, $soname, $libfile) = @_;
my @files;
@@ -754,7 +756,13 @@ sub find_symbols_file {
} else {
push @files, "$Dpkg::CONFDIR/symbols/$pkg.symbols.$host_arch",
"$Dpkg::CONFDIR/symbols/$pkg.symbols";
- my $control_file = get_control_path($pkg, 'symbols');
+ my $control_file;
+ if (exists($symbols_file_cache{$pkg})) {
+ $control_file = $symbols_file_cache{$pkg};
+ } else {
+ $control_file = get_control_path($pkg, 'symbols');
+ $symbols_file_cache{$pkg} = $control_file;
+ }
push @files, $control_file if defined $control_file;
}
--
2.11.0
